Southwest Oregon Salmon Restoration Initiative

Section A: INTRODUCTION TO THE SOUTHWEST OREGON SALMON RESTORATION INITIATIVE

1. The Planning Mandate

2. Oregon Coastal Salmon Restoration Initiative

3. Southwest Oregon Salmon Restoration Initiative

4. The Southwest Oregon Initiative Approach - Phase 1
a. Stabilizing the Coho Population
b. Phase 1 - Implementation

5. Watershed Councils, Agencies, Landowners, and the Southwest Oregon Initiative

6. The Southwest Oregon Initiative Approach - Phase 2
a. Restoring the Coho Population to Sustainable Levels
b. Implementation of Phase 2
c. Guidance Document Method of Analysis

Section B: SOUTHWEST OREGON ECOSYSTEM CONDITIONS AFFECTING COHO PRODUCTION

Step 1: Establish Current Environmental Conditions Existing in the Southwest Oregon Region.

1. Physical Environment
a. Climatic Factors

2. Impacts of Mining Upon Stream Structure and Habitat

3. Impacts of Forest Harvest and Management Practices Upon Watersheds

4. Impacts of Agriculture Upon the Rogue Basin Watersheds

5. Urban Land Uses and Impacts

6. Water Resources and Stream Environments
a. Recreational Use of the Waterways

7. Aquatic Wildlife Habitat Conditions

8. Impacts of the Ocean Environment

9. Impacts of Predation Upon Fish Production

10. Summary and Implications of Ecosystem Effects

Section C: HISTORIC FACTORS AFFECTING COHO PRODUCTION, AND CURRENT LIFE-CYCLE NEEDS.

Step 2: Identify Historic Fish Management Practices and Environmental conditions and Their Effect Upon Coho Production. Current Coho Life-Cycle Habitat Needs Within the Rogue and South Coast Basins.

1. Historic Salmon Populations

2. Hatchery Influences

3. Rogue Basin Coho Production

4. South Coast Coho Production

5. Summary

Section D: NATIVE COHO POPULATION VARIABILITY

Step 3: Establish a Minimum Viable Coho Population Size

1. Coho Population Variability
a. Concept of Population Variability
b. Stabilizing the Population

2. Coho Population Variability within the Southwest Oregon ESU.
a. Method 1: Historic Level of Survivability
b. Method 2: Ricker Stock Recruitment Model
c. Method 3: Habitat - Based Approach to Determining Escapement Goals
d. Summary of Estimates

3. Conclusions

4. Benchmarks for Coho Recovery in the Rogue and South Coast Basins

Section E: NATIVE COHO DISTRIBUTION IN SOUTHWEST OREGON

Step 4: Establish the Coho Distribution in the Southwest Oregon Region

1. Distribution and Production
a. Importance and Method for Establishing Distribution
b. Historical Versus Current Distribution
c. Analysis of Population Distribution, Overall Numbers and Habitat Condition

Section F: HIGH VALUE NATIVE COHO HABITAT AREAS AND THEIR CONDITION

Step 5: Determine Locations of Existing High Value Native Coho "Core" Habitat Areas, and Assess Their Conditions.

1. Identification of Native Coho Core Areas
a. Method of Core Area Identification
b. Methods Used to Evaluate Core Area Habitat Conditions

2. Core Area Characteristics
a. Overview of Rogue Basin and South Coast Core Areas
b. Rogue Basin Core Area Characteristics
c. The South Coast Basin Core Area Characteristics

3. Habitat Conditions Aggregated for the Rogue and South Coast Region

4. Other "High Value" Coho Production Areas

Section G. PLANNING GOALS AND PRIORITY ACTIONS FOR STABILIZING THE ROGUE AND SOUTH COAST NATIVE COHO POPULATION.

Step 6: Establish Planning Goals and Priority Actions As A Basis for Implementation.

1. Analysis Process

Section H: WATERSHED COUNCILS AND THEIR ROLE IN IMPLEMENTING ACTIONS.

Step 7: Specify Habitat Restoration Actions Needed Within Watershed Core Areas, and Evaluate What Watershed Councils Are Doing to Address Them.

1. Watershed Councils and the SOSRI

2. Roles and Responsibilities of Local Watershed Councils

3. Integration of Watershed Councils into the SOSRI
a. Watershed Councils in the Rogue and South Coast Basins.
b. Core Area Restoration Actions to be Undertaken by Watershed Councils

Section I: ADVANTAGES AND LIMITATIONS OF THE SOUTH-WEST OREGON SALMON RESTORATION INITIATIVE

Step 8. Identify Assurances and Hindrances to Implementing Actions.

1. Implementation Plan
a. Aggregation of Actions
b. Identification of Actions
c. Coding of Actions
d. Assurances of Implementation
e. Hindrances and Barriers
f. Factors Currently Limiting Watershed Council Process

2. Monitoring Strategy

3. Adaptive Management in Habitat Restoration

4. Disaggregation of the Rogue and South Coast Basins From the Klamath ESU

BIBLIOGRAPHY

GLOSSARY

APPENDIX 1. WATERSHED CORE AREA HABITAT ASSESSMENTS AND ACTION PLANS.

APPENDIX 2. FEDERAL, STATE, AND LOCAL AGENCY ACTIONS FOR THE PROTECTION, MAINTENANCE AND RESTORATION OF COHO CORE AREAS

APPENDIX 3. COHO DISTRIBUTION MILES BY WATERSHED

APPENDIX 4. SUMMARY OF PUBLIC COMMENT AND CRITIQUE

LIST OF TABLES

Table 1: Road Development on Public Lands in Rogue and South Coast Basins.

Table 2: Coho Life-Cycle Model for the Rogue Basin.

Table 3: Coho Life-Cycle Model for the South Coast Basin.

Table 4: Model Coho Production Rates Under Different Ocean Survival Rates and Habitat Quality Conditions.

Table 5: Historical and Current Distribution of Coho Habitat Within the Rogue and South Coast Basins.

Table 6: Coho Core Areas by Watershed.

Table 7: Rogue Basin Coho Core Area Habitat Conditions.

Table 8: South Coast Basin Coho Core Area Habitat Conditions.

Table 9: Summary of Environmental Conditions of Rogue and South Coast Basins.

Table 10: Priority Core Areas Limiting Factors for the Rogue and South Coast Region.

Table 11: High Value Coho Habitat Areas, by Watershed.

Table 12: Other Concerns of Regional Priority in Southwest Oregon.

Table 13: Core Level Goals and Actions to Address Regional Limiting Factors.

EXECUTIVE SUMMARY

Currently there is a multi-state effort to address the decline of salmon on the West Coast. As part of this effort the National Marine Fisheries Service has divided the coast into a number of coho salmon population regions based on their genetic similarities. The coho regions are referred to as Evolutionarily Significant Units (ESUs). One of these coho ESUs bridges southern Oregon and northern California and is referred to as the Klamath Mountains Province (KMP).

Coordination between the State of Oregon (Coastal Salmon Recovery Initiative) and California on the shared KMP ESU has been limited. While the State of Oregon has been supportive and involved in the development of a recovery strategy for the Oregon side of the KMP, the State of California governor's office has not proceeded with the same level of effort. This has resulted in a split effort between Oregon and California in addressing native coho recovery within the KMP ESU.

The State of Oregon's Recovery Initiative in southern Oregon has been spearheaded primarily by a voluntary partnership of local watershed councils, stakeholders and government agencies from throughout the southwest region. This partnership was coordinated by the Rogue Valley Council of Governments and primarily funded by the Lower Columbia Area Office (Portland) of the Bureau of Reclamation. Additional funding, guidance and technical support was received from the State of Oregon, U.S. Fish and Wildlife Service, S.W. Oregon Resource Conservation and Development and For Sake of the Salmon (a multi-state non-profit group). The southern Oregon effort is referred to as the Southwest Oregon Salmon Restoration Initiative (Southwest Initiative).

Attached is the Phase 1 document of the Southwest Initiative. The Phase 1 document provides the basis for the coordinated and highly focused effort being undertaken to stabilize the native coho population in southwest Oregon from further decline. The Phase 1 document is an assessment and a call for action based upon methodology identified by the National Marine Fisheries Service (NMFS). The approach includes:

• Identify the causes for the decline of coho salmon in southwest Oregon.

• Identify which of the causes are of regional significance (i.e. - a priority).

• Identify the current situation of the coho population and its habitat.

• Identify targets to be used for coho habitat to indicate a stabilized condition.

• Identify what actions will be taken to reach the targets.

• Identify what assurances there are that the actions will be taken.

• Identify how changes will be measured and evaluated.

A key reason for the high level of support for the Southwest Initiative is the pervasive and firm belief that we can do more to recover our native coho by developing and implementing a plan quickly and effectively than we can by waiting until an Endangered Species Act listing occurs and then developing a plan. Through this initiative the partners have shown their willingness to undertake preemptive steps to definitively identify and implement actions which, based on the best information available, will improve salmon habitat and increase populations to a stable level; and in due course, restore the native populations to sustainable levels.

Primary to the development of the Initiative was the identification of current trends and an understanding of the causes unique to our region which are directing them. Federal, State and local agencies and 9 watershed councils contributed a wide range of information to the Rogue Valley Council of Government's technical team for collection and assembly. As part of assembling this information, the team reviewed technical literature, Federal and State databases, watershed council assessments, Forest Service and Bureau of Land Management assessments, oral histories and local information about the basin's fish populations and ecology. Federal, state, and local biologists familiar with the southern Oregon region participated in the development and critique of the document.

Another critical element of the document included the identification of the "best of the best" coho areas, referred to in this document as "core" areas. The Oregon State Governor's Salmon Recovery Initiative Science Team proposed 27 such areas for the southwest region. The purpose of these core areas was to identify focus areas for measuring current conditions and monitoring the success of ongoing restoration efforts. The core areas provided by the state were evaluated and modified locally based on current native coho population numbers, habitat qualities, and factors limiting survivability. Information on secondary "high value" coho habitat areas was also compiled in the final Phase 1 document. These analyses provided the basis for identifying measures needed to stabilize the native coho population.

Major factors limiting coho production in southwest Oregon were high water temperatures and low flows in rearing areas, along with poor riparian habitat, sedimentation, loss of instream structure and channelization. Some of these factors are naturally occurring and relate to climate, changing ocean conditions, and global ecological trends. Others are the result of past and current human activities relating to logging, agriculture, mining, urbanization, and commercial harvest.

A Draft of the Phase 1 document was circulated for public and agency review with comments solicited from September 1996 thru January 1997. Comments of critique are included in an Appendix and incorporated into the latest document revision.

A core tenant of the Southwest Initiative is that sub-basin watershed councils (with support of the Rogue Valley Council of Governments and the Governor's Watershed Enhancement Board) will assume the primary role for the more detailed, site specific assessments and undertaking restorative actions within individual watersheds. These same watershed councils are currently updating their sub-basin Assessments and their Action Plans to include the regional concerns identified within the Phase 1 document. Local communities and government agencies will provide ongoing technical support to the watershed councils to increase the technical accuracy of their plans.

The Phase 1 Plan will be followed by a more comprehensive Phase 2 "Guidance Plan." The Guidance Plan will incorporate all the site specific information and proposed actions developed by the watershed councils. It will evaluate the significance of their plans to the coho population as a whole, measure the level of commitment, estimate the total benefits to the native coho population and be the basis of the Southwest Oregon Recovery Effort.

Watershed councils and local communities understand planning is not enough. They are already actively implementing on-the-ground projects to improve native coho habitat. The partners recognize that the native coho population must be stabilized from further decline before recovery can begin. The Phase 1 document identifies stabilization as being reached when the southwest Oregon population consistently remains above a minimum level of genetic survivability, which is 3,600 native coho. We calculate that this minimum can be maintained by keeping an ongoing average population of at least 8,000 natives. Recent returns on the Rogue River and the South Coast have demonstrated that we are within reach of this amount. During recent years we have seen a returning adult native population of up to 9,757 at Huntley Park on the lower Rogue River. [This estimate does not include the returning population of the south coast.] Based on these figures, it is certainly reasonable to believe that the average 8,000 number will be attained in the near future, considering no commercial harvest for coho is permitted.

Locally, we know that the process we have started is only the beginning of the road. It has taken about 100 years to put the populations of native coho salmon in the Rogue and South Coast Basins in their current stressed condition and it will take some time to achieve a satisfactory level of recovery. This Phase 1 document outlines the first steps the people of southwest Oregon are taking to bring the coho population back to being an integral part of their heritage.

Mary DeLaMare-Schaefer
Executive Director, RVCOG

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Abstract: The Southwest Oregon Salmon Recovery Initiative
proposes to stabilize declining coho populations in our region,
and then, in due process, restore these populations to viable
and sustainable levels.

This section describes in general terms how the plan was
initiated and the premises upon which it is built.

A.1 The Planning Mandate.

In 1990 participants in the widely acclaimed 'Salmon Summit' called by Senator Mark O. Hatfield, concluded that federal and state natural resource agencies lacked an effective, integrated plan to address salmon recovery in the Pacific Northwest states.⁽¹⁾ Subsequently, the National Research Council (NRC) was commissioned to conduct an independent audit of current agency policies and actions, and recommend options for recovery action. In 1992, the NRC recommended that the highest priority effort should be directed toward rehabilitation of critical salmonid habitat areas, at the watershed level of effort. The committee proposed that the relevant agencies in the Pacific Northwest, including the National Marine Fisheries Service (NMFS), agree on a process to formulate salmon recovery plans in advance of listings under the Endangered Species Act , and that the Pacific Northwest states, acting individually or through the Northwest Power Planning Council, provide technical and financial assistance to watershed-level organizations to prepare and implement recovery plans.⁽²⁾

In response, the NMFS called for regional watershed restoration efforts to meet Endangered Species Act mandates for declining salmon populations in Oregon.⁽³⁾ NMFS is seeking cooperative efforts among diverse stakeholders to work together to identify restoration needs and recovery actions. They call for a naturalistic approach which takes account of a range of complex biological habitat systems and the life cycle characteristics of salmonid fisheries at the bioregional level. NMFS recommends using an approach of adaptive management of natural resource and habitat areas. In this fashion, they have called for pre-emptive recovery plans to be developed under the framework of the Endangered Species Act to foster cooperative, bioregional, adaptive agreements in watersheds.

Formulation and adoption of approved plans could forestall a listing under the Endangered Species Act to protect threatened salmon populations. The NMFS could decide to not act upon a filing action for two years after a state certifies that a recovery plan is being developed. This

would allow time for NMFS to adopt or reject the proposed plan. The specific objectives recommended by the National Research Council were to:

1. Identify all the causes of salmon mortality, the magnitudes, and the uncertainties of the estimates.

2. Recommend ways to reduce mortality, and assess probable effectiveness and drawbacks.

3. Identify probable costs of each method of reducing mortality (including market and non-market costs).

The State of Oregon has designated the Oregon Coastal Salmon Restoration Initiative as a process to evaluate the status of coho populations in Oregon. The CSRI Science Team has concluded that while some coho stocks may be depleted, the three groups of Oregon coho salmon do not meet the criteria for listing as threatened or endangered under the Oregon Endangered Species Act⁽⁴⁾. Oregon's Wild Fish Policy has adopted a minimum threshold of 300 breeding fish per stream per year, and currently Rogue and South Coast Basin coho populations exceed this minimum threshold.⁽⁵⁾

Private groups in Oregon however, have petitioned the NMFS to list selected coho stocks under the provisions of the Federal Endangered Species Act. As a result, the State of Oregon has prepared a salmon initiative, and is in the process of conducting status population assessments and developing pre-emptive recovery plans for potentially threatened stocks. The Initiative is intended to address the above recommendations of the NRC, to develop a pre-emptive approach to the listing of coho salmon.

A.2 Oregon Coastal Salmon Restoration Initiative.

The State of Oregon's approach to addressing coho salmon (Oncorhynchus kisutch) recovery is through initiating the Coastal Salmon Restoration Initiative (CSRI).⁽⁶⁾ Under this Initiative the Governor has directed state agencies to develop a Strategic Plan which, using existing laws, presents additional protective measures to be implemented by all levels of government and private resource managers. The Governor's strategy addresses harvesting, habitat, hatcheries, and hydropower (of limited concern in the South Coast area). The initiative includes a review of existing regulations, policies, programs, and voluntary efforts, as well as identifying new partnerships. Southwest Oregon watershed councils have chosen to collaborate with the state in this endeavor.

One purpose of the Initiative is to mobilize coastal communities, along with state and local governments, and watershed councils so they will take the actions necessary for maintaining, protecting, and restoring salmon populations to healthy levels coast wide. The Initiative is linked to a corresponding effort in California to encompass the entire Klamath Mountain Province fisheries. The CSRI Team submitted the first draft of the State's plan (including the Southwest Oregon Salmon Recovery Initiative) to NMFS on October 1, 1996. A revised final plan is being submitted in late February, 1997.

A.3. Southwest Oregon Salmon Restoration Initiative.

The Southwest Initiative is a regional strategy used to combine local and agency efforts to foster salmon recovery throughout the South Coast region. The Southwest Oregon Initiative is prepared in conjunction with the Oregon State Initiative, but it also attempts to move beyond the state plan in developing a salmon habitat restoration plan specifically for southwest Oregon. The Southwest Oregon Initiative will use a regional assessment approach to identify site specific actions to address the problems causing the decline of the coho population on the Oregon side of the Klamath Mountain Province Evolutionarily Significant Unit.

One feature of the Southwest Oregon Initiative approach is for local watershed councils to represent local stakeholders, and to serve as the lead planning bodies in identifying coho habitat restoration needs and actions within their watersheds. The site specific information they have accumulated on historic and current fishery conditions in their local areas, along with information from sub-basin watershed assessments and other sources, is aggregated and analyzed at the regional scale to define region-wide problems.

Figure 1: Flowchart of Phase I and Phase II Planning Activities.

This document focuses on Phase I of an overall larger program and how Phase I and the following Phase II segments of the program interrelate.

Phase I - Stablize coho populations - Immediate short term (0-10 yrs.) response.

Phase II - Recover coho populations - Long term (10-50 yrs.) responses

Graphics not available in this document.

Another feature of the Southwest Oregon Initiative strategy is to utilize a modified "patient-template" life-cycle model,⁽⁷⁾ which focuses upon the specific habitat needs for each stage of the coho life cycle. In principle, a template of essential habitat needs (or current conditions) is developed for each life stage, then compared to a template developed for potential habitat conditions and coho production that could be accomplished if the habitat were restored to 'best achievable conditions'. The process enables the description of both present and potential habitat conditions, and links an 'Action Plan' to address the restoration needs identified in the evaluation process. The approach results in first, implementing actions which stabilize the present coho population in order to prevent further decline, and later in implementing actions which help restore the population to viable, sustainable levels.

A.4. The Southwest Oregon Initiative Approach - Phase 1.

A.4.a. Stabilizing the Coho Population.

Phase 1 of the Southwest Oregon Initiative is intended to stabilize the native coho population at a level higher than the minimum genetically viable population level. The major part of this document addresses Phase 1 objectives. Key elements of this stabilizing strategy are:

• Describe the Rogue and South Coast current ecosystem conditions, factors affecting current trends in coho habitat conditions, and their effects upon coho propagation for southwest Oregon (see Section B);

• Describe coho habitat needs throughout their life cycle (See Section C);

• Identify the historic variability of the coho population and define a viable population range which can be used to measure the success of recovery efforts (see Section D);

  Identify the historic and current distribution of coho habitat and develop policies and actions which maintain the range of the natural population (see Section E);

• Designate critical coho habitat areas, along with other biodiversity areas and refugia, where immediate protection and restoration actions should be potentially targeted (see Section F);

• Identify the region-wide limiting factors affecting coho production within critical habitat areas (see Section F);

• Prioritize habitat restoration actions, based upon the primary limiting factors (see Section G);

• Inventory and evaluate existing actions being undertaken, and implement additional priority actions as warranted (see Section H);

• Specify the roles and responsibilities of state, local governments, and other organizations, and foster cooperation among subbasin, basin and regional/state natural resource management entities (see Appendix 2);

• Monitor plan and project results, and modify actions in accordance with 'Adaptive Management' principles, and measure changing trend conditions (plan to be developed for the Phase 2 - Guidance Plan).

(1) Examine the spatial distribution of coho habitat in their watershed and concur or recommend modification to include additional coho habitat areas (maps were provided for reference);

(2) Identify significant 'wellspring' areas within their watershed that should be evaluated as high value coho core areas,⁽⁸⁾ alternate core areas, key watersheds, other officially recognized natural areas, etc.;

(3) Identify additional 'high value' ⁽⁹⁾ coho habitat areas within the watershed that might be addressed;

(4) Identify current conditions, problems, and limiting factors to coho survival in the core habitat areas;

(5) Develop protection/restoration measures for core habitat areas and prepare a workplan that has a high probability of leading to successful restoration action. All watershed plans specify near-term actions (1-10 years) and long-term needs and goals (10-50+ years) for the watershed;

(6) Identify project/funding needs, obstacles and assistance necessary to overcome barriers to project implementation. [This section is to be developed in the Phase 2 Guidance Plan, which will be prepared subsequently]

A.5. Watershed Councils, Agencies, Landowners, and the Southwest Oregon Initiative.

The Southwest Oregon Initiative's approach outlined in this document is a process - not a result. It is a voluntary planning tool, not a mandate. The Initiative provides a vehicle through which a region can set environmental priorities and measure collective results toward community-wide goals.

The Initiative's process does not supersede the management plans, implementation strategies or funding priorities of any watershed council or recognized jurisdiction. Nor does it supersede the legal authority of any agency or the rights of landowners. This document offers a tool to provide planning guidance and a yardstick to measure results at a regional level. What it offers is:

*...a way for our region to use our collective wisdom to document existing coho habitat conditions as a baseline inventory for the Oregon side of the Klamath Mountain Province (KMP) Evolutionarily Significant Unit,

*...a way to collectively agree on which current habitat conditions are of regional concern and regional priorities,

*...a way for individual agencies, watershed councils, and landowners to understand their role in the overall management, enhancement, and long-term recovery of the KMP coho population,

*...a way for the region to track its progress toward achieving regional habitat improvement goals by documenting site-specific actions. This also provides a way to identify which, if any, habitat concerns are not being adequately addressed,

*...an opportunity to integrate regional priorities into local, state, and federal management planning efforts.

A.6 The Southwest Oregon Initiative Approach - Phase 2.

A.6.a. Restoring the Coho Population To Sustainable Levels.

Phase 1, discussed above, consists of assessing current conditions and identifying actions necessary for stabilizing a viable native coho population. Included in Phase 1 is the identification of strategies to be used in Phase 2. Phase 2 incorporates a more comprehensive examination of habitat throughout the entire native coho range in southwest Oregon. Phase 2, although identified herein, will be completed at a later date.

Key elements of the Phase 2 strategy, which are meant to be used to restore the coho and steelhead populations to healthy levels, are:

• Recognize the 'uniqueness' and special qualities of watersheds, and their contribution to the cultural, economic, and biologic functioning of the basin ecosystem;

• Complete a comprehensive regional assessment of coho and steelhead life history habitat needs within the Rogue and South Coast Basins;

• Develop estimates of current and potential native salmon production throughout the southwest Oregon region;

• Identify and prioritize habitat restoration needs both within and across land ownerships and jurisdictions for the entire Rogue and South Coast basins;

• Implement the restoration actions necessary to enhance watershed quality, at both the basin and site-specific levels;

• Monitor project outcomes and evaluate recovery success for sustaining the overall native salmon populations.

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Section B: SOUTHWEST OREGON ECOSYSTEM
CONDITIONS AFFECTING COHO
PRODUCTION

Step 1: Establish Current Environmental Conditions
Existing in the Southwest Oregon Region.

Abstract: The reasons for the decline in coho populations in the Rogue and South Coast basins have been a century in the making, and may well take a century more in their recovery. This section portrays the historic and current ecosystem conditions in the basins for the population as a whole, the forces and causes of change in those conditions, and the current trends, both within the basin ecosystems, and the native fisheries. Many of the conditions are amenable to change through a change in management. Other conditions need study and the careful collection of data to determine their potential effect.

This section describes the basic environmental conditions of the Rogue and South Coast basins and their influence upon coho propagation.

B.1. Physical Environment. Although they are both within the Klamath Province in Southwestern Oregon, the Rogue and South Coast hydrologic basins are considered separate ecosystems, primarily due to the influence of coastal and inland climatic effects. The Rogue Basin is characterized by rugged, steeply dissected mountain ranges, a Mediterranean climate, and forest areas fragmented by soil types, rainfall, wildfire events, and alternative land uses. The majority of hillslopes have been disturbed by a century of human use (settlement patterns, forest harvest practices, road systems, mining, and agriculture). Tributary streams generally follow the northeast to southwest orientation of mountain valley drainages. Most drainages are highly erosive, producing inner gorges and alluvial plains. There are multiple 'key, and/or critical' watersheds within the basin for wildlife use.

The South Coast Basin has similar topography, created by similar natural geological forces, but differs by being vegetated by a temperate, moist coastal climate. Its valleys are less altered by human effects, with fewer private landownerships. The forests are characterized by a mosaic of mature, old-growth, and harvested stands, located within early and mid successional forests.

B.1.a. Climatic Factors. Climate is the single greatest factor directing the ecology of the Rogue and South Coast basins, and ultimately, fish production. The basin's location, just above 42° north latitude, is unique in the global energy balance, being where the intensity of global solar energy exposure shifts from deficit (north) to surplus (south).⁽¹⁰⁾ Southwest Oregon is marked by the convergence of four distinct climatic zones: northern temperate, western coastal, eastern high desert, and southern Mediterranean; making the basins highly vulnerable to climatic shifts. Such shifts affect regional conditions including temperature and precipitation, vegetation composition, and migratory patterns of wildlife.

Several major climatic shifts have occurred within geologic history, which directly link to current ecological trends. The causes of global shifts in climate and geology are still unclear. There is evidence that the earth has tilted in its rotation (perhaps more than once during the five billion year geological epochs), exposing whole hemispheres to increased (or decreased) solar radiation. Some 780,000 years ago the earth's magnetic field flipped from south to north (which may have occurred more than once in geological history), producing unknown effects upon the world's environment.⁽¹¹⁾ These events reflect the longest term cycles impacting southwest Oregon.

Within the more recent Holocene era, there is evidence that solar eruption cycles of the sun, range an amazingly consistent 22 years in length, significantly alters solar radiation within shorter term cycles. Rainfall and temperature data for the Rogue Basin appear to reflect this cycle, but causality is not yet confirmed. Within the subcentury cycles are possible 7-10 year cycles, featured by sharp variation in local rainfall and temperature from year to year. The greater geologic climatic trend for southwest Oregon appears to be heading toward hotter and dryer conditions (interspersed with short run wet cycles). These patterns superceed any possible effects of commerce induced global warming influences. If these trends are valid, natural climatic conditions may become an overwhelming limiting factor affecting future salmonid propagation in southwest Oregon.

Although findings are still inconclusive, west coast dendrochronologists have identified a 22 year drought cycle in the growth rings of ancient cedars and Ponderosa pine trees⁽¹²⁾. This cycle corresponds with sun solar burst events, at least in data for this century. Some climatologists have predicted that solar radiation bursts may heat the Great Plains and southwestern desert states, prolonging the lifespan and intensity of continental high pressure zones, and also warming the South Pacific ocean to produce el nino events⁽¹³⁾. The combination and interaction of these two forces (as well as other earthly forces) increases the variability and extremes of weather events, resulting in short term temperature shifts and flood-drought cycles for local areas, and longer term shifts in regional continental climates (east coast snows, mid-west floods, Texas droughts, and Florida hurricanes). Through complex linkages, distant weather events eventually come to bear upon the ecology of the Rogue and South Coast Basins. In ways only vaguely understood, these climatic trends are linked to cycles and variability in ocean conditions, which significantly affect salmonid propagation in southwest Oregon.

Beyond the controlling global forces, there is wide variation in climate conditions within the Coastal and Rogue basins. The regional climatic conditions are largely influenced by the topography of the Coastal and inland Cascade mountain ranges and in their location relative to the ocean. Marine precipitation is highest along the coastal range and on windward slopes of the mountains, producing over 100 inches of rainfall in winter and almost none in summer. Rainfall is largely influenced by the predominant western continental airflow pattern, whereby the "jetstream" follows a middle air route into the Cordilleran mountains and Great Plains. Weather is driven by continent size low pressure systems which form in the Pacific Ocean, and intrude when intra-continental high pressure zones are diminished through winter cooling. Within the Cascade Mountains, condensation is accelerated by dynamic and/orographic cooling when the air rises to cross mountain ranges, and is diminished by warming through compression as it descends the leeward slopes. This pattern is most pronounced in winter, which produces the largest seasonal rainfall throughout the basins, causing heavy winter runoff and high streamflows, which can flush coho juveniles out of the systems.

In summer months, continental high pressure areas build from inland heating, which blocks the horizontal coastal flow and forces it northward into Canada.⁽¹⁴⁾ Thus summer rainfall is sharply reduced for southwestern Oregon. Seasonal swings in inland and Great Plains warming patterns produce a whip-lash effect in weather patterns, creating sharp yearly fluctuations of temperature and rainfall within the Rogue Basin. Precipitation data from Medford, Oregon show a definable drought, wet, and new drought cycle for this area since 1910 (see Figure 2)⁽¹⁵⁾

.

Figure 2. Medford Precipitation Data.

B.2 Impacts of Mining Upon Stream Structure and Habitat. The earliest and perhaps largest human caused environmental change within the Rogue basin occurred from early gold mining in southwest Oregon. Miners moved to the Rogue Basin following the California gold rush, and set up small-scale placer mines in the 1850s-60s. LaLande⁽¹⁶⁾ reports that early miners in the Applegate drainage sometimes found more salmon in their sluice boxes than gold, often harvesting the fish for sale to finance continued mining. Even so, LaLande predicts that the placer mines probably had minimal impact upon stream water quality, because of their small size and limited operation.

Larger scale hydraulic mining developed during the 1870s, which dumped up to 1,500 cubic yards of tailings into the watercourse daily. In 1875, the Jacksonville newspaper reports that "streams ran red" from the mining sediment, which inevitably smothered salmon redds and rearing areas and degraded water quality. The 'house-sized' mining equipment and tailing piles no doubt moved and rerouted stream channels in unknown ways. Natural storm events accentuated the damage through transporting tailings miles downstream. The sediment loads were most severe during winter and spring months, which is the critical period for rearing juvenile chinook and coho. Sediment deposition and chemical contamination leached from mine tailings, also destroyed macroinvertebrate habitat and food sources, which exacerbated the survival of fry and juveniles.

In the 1930s the Oregon Department of Geology required miners to construct settling ponds, which greatly reduced downstream sedimentation. Mining decreased during the "Depression Period," and has continued at a much reduced level. Since then, salmonid production on these rivers stabilized at lower levels.⁽¹⁷⁾

B.3. Impacts of Forest Harvest and Management Practices Upon Watersheds. The forests of the Rogue Basin have been almost completely transformed within the past 100 years. Aside from the lowlands, which were cleared for agricultural and residential use in the first early

settlements, the forests remained largely uncut until harvest surged during World Wars I and II. Fire suppression practices developed around the turn of the century, which resulted in an increase in tree and shrub density, fuels accumulation, and diminished open areas. Large scale clear-cut harvesting emerged around World War II, which resulted in increased erosion and sedimentation of tributaries, decreased watershed storage, and encouraged a species shift to more combustible, high density Douglas Fir forest stands. Approximately 50,000 miles of logging roads have been constructed over the years in forested areas (both public and private lands), which are now being closed at the rate of 2-5% per year to reduce erosion and sedimentation.

LaLande notes that overall, much more of the watershed is forested now than a century ago, with more dense conifer cover than previously ⁽¹⁸⁾ (presumably because of fire control practices). Accompanying this change, forest insect and disease infestations are probably far more prevalent as a result of this high-density undergrowth pattern. An exception are the riparian zones of lower and middle reaches of rivers, which have been reduced in size through development. Grassland, glade, and meadow areas within forests have shrunk to remnants of their former size, and encroached by brush species. Tree species have shifted from Ponderosa and sugar pine to Douglas Fir in the mid to upper elevations, with dense copses of 'scrub oak' on the hillsides and lower elevations. Competition for moisture accentuates tree stress and disease conditions in many areas throughout southwest Oregon.

Since 1910 fire suppression practices and timber harvest patterns have combined to produce a "younger" set of biotic communities across the landscape than earlier periods, composed of dense shrubbery and tree stands. Ecological succession is often interrupted by changes in the physical environment (fire, drought, temperature reversals), creating a mosaic of secondary and younger secession biota across the landscape. With the combination of topography, climate and soil, biotic zones range from the warm, wet Humid Transition and the semi-arid Upper Sonoran, to the Arctic-Alpine. Through time a multitude of phytosociological plant communities have evolved, presenting a series of overlapping ecological relationships.

As a result of land clearing through harvest and development, riparian areas in many river reaches have shrunk, and canopy cover decreased. Many stream channels have widened, become more shallow, and reduced in sinuosity and complexity. With time, baseline stream water temperatures have increased and spawning and summer/winter rearing habitat degraded. For the most part, beaver populations have been extirpated from many of the basins, which reduces their historic contribution to the preservation of riparian areas and enhancement of summertime flows⁽¹⁹⁾.

Wood smoke pollution is probably diminished from historic times, as fire suppression has been more effective. Indians practiced controlled burning of the landscape on a mosaic pattern, burning most of the forest area each 10-15 years, and early travelers along the Applegate Trail repeatedly report in their journals that the valley was filled with smoke. Indians used controlled burning to replenish meadows for wildlife and hunting, to clear trails and maintain open areas under the forest canopy, and fertilize new growth in plants and shrubs. Typically however, the fires were low intensity and rarely burned more than a few hundred acres (usually only a few acres). The fires cleared the combustible underbrush, reducing the overall fuels load of forests throughout the entire basin and probably did little to impact riparian tree cover.⁽²⁰⁾ In much of the lowlands in the Rogue Basin, residential expansion has followed forest harvest, permanently converting future land use.

Road density on public lands in the Rogue Basin is moderate, with some 14,000 miles of logging roads within the watershed still in use (approximately 3.5 miles road/per square mile). Most of the roads are unsurfaced, which significantly alter hydrological patterns and degrades water quality of upland areas (see Table 1).

Table 1. Road Development on Public Lands in Rogue and South Coast Basins.

National Forest or BLM District	Total Miles (All types)	Road Density (Mi/sq.mi.)
Rogue River NF	2,782 (4477 km)	3.92
Siskiyou NF	2,949 (4746 km)	3.28
Medford BLM	5,628 (9057 km)	3.92

Source: Table V-2. Summary of road development on public lands in the range of the northern spotted owl. Forest Ecosystem Management: An Ecological, Economic, and Social Assessment. Report of the Forest Ecosystem Management Assessment Team. U.S. Department of Agriculture, July, 1993.

Over 2.8 million acres, or nearly 88% of the total Rogue Basin is forest land. Approximately 80% of both basins are public lands, leaving only 20% in private ownerships. However, the majority of critical (and core area) coho habitat areas are located on private lands, thus need special attention.

B.4. Impacts of Agriculture Upon the Rogue Basin Watersheds. Agricultural clearing in the Rogue Basin developed slowly until the turn of the century, expanded considerably during the two World War periods, then slowly began to evolve to the current mix of farming and residential "Hobby Farms" which exists today. The early impacts were to reduce forested lands, narrow riparian areas for livestock and developmental use, and divert stream flows for irrigation use⁽²¹⁾. Lowlands were drained, hummocky areas were leveled, and stream channels straightened to increase drainage.

The development of irrigation water sources began shortly after settlement in the Rogue Valley. By 1900, most tributary streams in the basin were 'over-allocated' for water rights, particularly for the summer and fall flows so important for rearing juvenile salmon. Multiple irrigation districts were formed in the Medford, Grants Pass, and Applegate valleys, even importing water from the Klamath Basin to water fruit orchards and pastures. Applegate Dam, Lost Creek, and Emigrant Reservoirs were constructed to control flood flows, and store irrigation water. The partially constructed Elk Creek Dam would have completed planned water management in the Rogue Basin, but has been halted because of alleged adverse effects upon water quality conditions (turbidity and temperature) and fish passage, especially coho. Irrigation diversions were rarely screened before the 1940s, which may have been a significant factor in fish declines⁽²²⁾.

Although the construction of Lost Creek and Applegate Dams has closed off some historic habitat range, they have also produced some beneficial effects for the fisheries. Reservoir releases increase river flows for salmonid survival during critical low flow periods, and both reservoirs are operated to reduce stream temperatures during the summer months. The impacts of Lost Creek Dam on both adult and juvenile coho were studied by ODFW and summarized in their 1991 Phase II completion report.

In the past 20 years, almost one-half of farmland in the lowlands of the Rogue Basin have been converted to 'residential farm units', most of which have preserved and continue to use their diversion water rights. Although residential water use is generally about one-third to one-half less than cropland use, the consumption of water on residential farmsteads is often transformed from cropland use to irrigating horse pastures and gardens. As a result, water diversion and consumption in the basin has not changed greatly from earlier levels.

B. 5. Urban Land Uses and Impacts. Changing patterns of land use within the Rogue and South Coast basins is constantly altering the landscape, and ultimately, coho habitat areas. The Rogue basin is experiencing rapid expansion of urban development among stream courses. The settlement pattern within the Rogue Valley is largely rural residential, and growing slowly, with scattered ranches, small farms, private forest lands, among sections of federal lands. In 1993, the Census population of Jackson County was 168,000; Josephine County, 62,649; and Curry County, 19,327. The urban areas of Medford-Ashland (population greater than 120,000), and Grants Pass ( about 50,000) are growing steadily and the cities are becoming regional governmental centers.

Residential development is often detrimental to riparian habitat areas, limiting the space for natural vegetation and stream channel development. Urban and rural land use includes 20.2% of the coho stream miles in the Rogue basin, compared to 4-8% in other coastal regions.⁽²³⁾ Communities in the Rogue basin have been among the 'more active' of the state in reducing pollution from sewage effluent discharge, spending over $50 million in the last decade, with perhaps more than that amount to be spent in the next decade.⁽²⁴⁾ Bear Creek (Medford/Ashland area) is responding to TMDLs applied around 1990, and other streams in the region are being monitored by DEQ for thermal pollution. South Coast cities tend to be smaller than those in the Rogue Basin, with correspondingly fewer municipal sewage pollution problems. Urban land use affects only 4% of the 1,640 miles of coho streams in the region.⁽²⁵⁾

Large units of the watersheds are protected from development and alteration by virtue of being in the domain of public lands. Land allocations and reserves in the watersheds are designated in the Northwest Forest Plan's Record Of Decision and the Medford District, Bureau of Land Management Resource Management Plan (RMP). These land allocations include Adaptive Management Areas, Late Successional Reserves, Big Game Management Areas, Research Natural Areas, Riparian Reserves, and 100 acre core areas for the northern spotted owl. The Medford District RMP has designated multiple RNA/ACEC areas (Area of Critical Environmental Concern). The RMP also designates elk management areas, and spotted owl habitat units.

B.6. Water Resources and Stream Environments. Hydrologic processes within the Rogue and South Coast basins have been altered from historic conditions⁽²⁶⁾. Overall, river systems have simplified and changed by management and development, which has significantly reduced the quantity and quality of salmonid habitat available for use. Major sections of rivers have been confined by land development and roads. These alterations have resulted in a decrease in aquatic complexity and diversity. Pool frequency and quality throughout most of the basins has declined from historic conditions and has become a 'potentially limiting factor' for most streams throughout the region (see Figure 3. Historic Pool Frequency). Generally, salmonid rearing habitat areas have become more degraded than spawning habitat areas throughout the basin.

Figure 3. Historic Pool Frequency in the Rogue Basin.

River flows in the Rogue Basin tend to peak earlier in spring and at higher levels, with lower corresponding summer base flows, creating a 'surging' pattern of water flows. Stream channels appear more prone to flood than in pre-settlement times, stream blow-outs tend to be bigger, and the absorptive capacity of the watershed is diminished. Yet, within the past decade, water quality parameters are slowly recovering from these conditions in some streams (such as Bear Creek, and mainstem Rogue River), as communities improve sewage treatment plants and reduce total maximum daily load (TMDL) problems and agricultural communities reduce/control chemical and fertilizer use.

The impact of water management practices upon fishery habitat quality continues to need improvement. The Center for the Study of the Environment conducted a regression analysis of determinants of salmonid production in the Rogue Basin and found that water quantity, or water flows constitute the overwhelming determinant of salmonid production, accounting for much more variance than hatchery production, troll catch, number of smolts released, etc.⁽²⁷⁾ The study is significant, but the analysis did not include measures of habitat quality and quantity, ocean habitat conditions, and the relationship/interaction with other species in production. Water quantity however, is a critical determinant of salmonid propagation in the Rogue Basin.

Relationships between salmonid production and life history, and freshwater physical factors, ocean physical factors, ocean harvest of salmon, freshwater harvest of salmonids, and the influence of hatchery fish have been examined in much greater detail for anadromous salmonids in the Rogue River Basin than most other Oregon coastal streams. These relationships are addressed in a number of ODFW research reports published between 1987 and 1994.

There were concerns that high streamflow events during winter months may have some impact upon coho fry and juvenile populations, in that untimely surges in river and tributary flows may move fish around through the system in disadvantaged ways.⁽²⁸⁾ Recent studies have shown that coho juveniles spend over a year in freshwater and may be vulnerable to flooding events, however, few juveniles rear in the mainstem of the Rogue River so dam releases have little or no effect on their survival. Also, the operation of Lost Creek Dam has minimal effect on the migration timing of adult coho salmon.

In another location, the present timing of water storage accumulation in the Applegate River may reduce river flows in some locations during critical periods for coho rearing, while water releases may help steelhead and chinook during other time periods. Flows from Emigrant Reservoir on Bear Creek are often cut off in late summer months during critical coho rearing periods. The impacts from human directed events (such as diversions and recreational use) may significantly affect water flow during critical coho production periods. The operations policy for reservoirs within the Rogue Basin should be evaluated for its impacts upon and potential use for coho propagation, particularly to provide flows for late summer rearing habitat needs.

Push-up dams are scattered on stream systems throughout the basins (probably in excess of 80 dams in the Rogue Basin). These dams are created by landowners and water districts as the need arises, and while most are "permitted," there is little control over their construction or mitigation for their environmental effects. Multiple agencies and landowners are working with the Illinois Valley Watershed Council to limit push-up dam construction on the Illinois River system, through alternative structures, improved design, and reduced use. The Applegate and other watershed councils are addressing the problem as well.

Water quality parameters throughout the basin are significantly degraded from historic conditions (see Appendix 1, Watershed Core Area Summary below). Current stream temperature standards as defined by DEQ are 13°C (55°F) for spawning, egg incubation, and fry emergence, and 18°C (64°F) for rearing.⁽²⁹⁾ Peak water temperatures in salmonid habitat areas may be up to 10°F. warmer than historic presettlement years (see Figure 4 below), occasionally approaching lethal levels in some reaches. The increase is primarily attributed to change in stream structure to wider, more shallow channels, the loss of riparian habitat and shade, and the loss of watershed subsurface aquifer storage capacity fostered by forest harvest practices. These changes (warmer water conditions) have resulted in generally lower dissolved oxygen (DO) levels throughout the system. Dissolved oxygen levels are 'potentially limiting factors' in some locations throughout the basins, primarily in areas with low summer flow conditions. Sediment and turbidity problem areas are also scattered throughout the basins, but are generally not limiting factors (see Table 15 below). Primary source areas for sediment are from hydraulic mining (Applegate, Middle Rogue), geological deposits of granitic soils (Bear Creek, Evans Creek), and steep erosive coastal streams.

Basin streams have also been impacted by thermal⁽³⁰⁾ and non-point source pollution from municipal and commercial development, and leaching of agricultural nitrates and pesticides. In 1987 the Bear Creek Subbasin was ruled in violation of Total Maximum Daily Load (TMDL) standards by DEQ, and is currently being remediated. Overall, water quality conditions are beginning to improve in the basins (such as Bear Creek and around Grants Pass), due to multiple landowner and municipal watershed restoration efforts.⁽³¹⁾

Figure 4. Historic and Current Peak Water Temperature Levels in Salmon
Habitat Areas.

B.6.a. Recreational Use of the Waterways. Studies of the potential impact of motorized boat traffic upon anadromous salmonids have come up with mixed results. There does not appear to be a significant impact on juvenile salmon or steelhead in the Hellgate Recreation Area from motorized boat use, or non-motorized use, for that matter (Satterthwaite, ODFW, 1994). However, based upon the conclusion of Sutherland and Ogle (1975), the ODFW believes that a significant percentage of the eggs and sac-fry of fall chinook salmon in the gravel are killed when exposed to motorboat traffic. Research conducted by the ODFW indicates that about 5% of the fall chinook spawn prior to October 1, and that the sac-fry remain in the gravel until late April (ODFW 1992). Consequently, ODFW has restricted jet motorboat traffic on the Rogue below Savage Rapids Dam from May 1 to Sept. 30. Since juvenile coho do not rear in the mainstem Rogue, there is no recommendation in regard to coho impacts.

B.7. Aquatic Wildlife Habitat Conditions. There are 21 key watersheds defined within the Rogue and South Coast basins (both the Forest Service "Key" watersheds and ODFW "Critical" watersheds are combined in this analysis). Other high quality 'biodiversity' areas also exist within the watersheds (such as spotted owl and elk habitat areas), but are not identified herein. The majority of core coho habitat areas are located within critical or key watersheds. High quality aquatic biodiversity areas are identified by watershed councils to receive particular attention for protection and restoration.

Historically, habitat biodiversity areas were created and maintained by fire disturbances. The present distribution of vegetation species throughout the watershed have been modified by fire control measures, creating alternative environments. There are 54 potential sensitive plant and animal species in the basins to be protected, along with habitat areas.

B.8. Impacts of the Ocean Environment. The ocean environment is by far the largest limiting factor for fish propagation, in that from 90 to 99% mortality occurs for anadromous fish that reach the ocean environment. Major sources of mortality are lack of food supply (from ocean upwelling), predation, and harvest.

The ocean food supply is probably the biggest determinant of coho health and propagation. Offshore ocean winds initiate upwelling from ocean depths to bring food nutrients, primarily chlorophyll, to the surface, which nourish ocean ichthyological fauna. Southwesterly winds (primarily from September through March) drive surface waters offshore, which are replaced by cold, nutrient rich subsurface water, with the reverse process occurring in the summer⁽³²⁾.

The strength and consistency of these flows along the Oregon coast usually makes them particularly productive for maturing fish. These offshore flows can be altered however, and redirected by the 'el nino' current, drastically reducing the upwelling pattern and corresponding food supply available to fish. In some recent years, returning salmon have been sharply smaller in size, perhaps due to these climatic changes.

The productivity of these off-coast flows may also account for the unique migration pattern of Rogue and South Coast basin salmonids, in that they typically migrate southward from Cape Blanco while salmonid stocks from Cape Blanco north tend to migrate north to Canada and Alaskan waters⁽³³⁾.

Environmental forces within the ocean have been linked to salmonid survival while in the marine habitat, and overall salmonid abundance⁽³⁴⁾. Although there are data only for this century, (thus the longer ocean cycles cannot be validated), there does appear to be 40 - 60 year cycles of major productivity.⁽³⁵⁾

Lawson reports that a high productivity phase occurred during the 1960s, which shifted to low productivity off the Oregon Coast in 1976, reducing marine survival and escapement for salmonids. Currently, the northern Pacific Ocean is speculated to be near the bottom of an ocean productivity cycle⁽³⁶⁾

and perhaps recovering .

B.9. Impacts of Predation Upon Fish Production.

There is some loss of fish to predation through the life cycle of coho, but the loss is judged to be insignificant in determining production trends for coho production⁽³⁷⁾. Major sources are from pennipeds, birds, hake and other fish, which feed on coho juveniles as they enter the ocean, and some loss from birds and squawfish in freshwater. The extent of loss is largely unmeasured, but is currently under study. Predation is addressed by each core area analysis in Appendix 1.

B.10. Summary and Implications of Ecosystem Effects.

There appear to be several ecosystem influences upon the Rogue and South Coast fisheries that will affect stabilization and future propagation of the species. The long-term regional climatic trends toward warmer and possibly more droughty conditions will make protection of critical habitat more challenging, sensitive, and complicated. These trends accentuate the need for high quality riparian environments and enhanced cooler, more stable stream flows, particularly for summer rearing habitat areas.

Land use and development practices increasingly intrude upon salmonid habitat areas, thus additional protections and safeguards will be needed. Public education to landowners about salmonid habitat needs is an essential element of any recovery program.

The abnormal disturbance pattern created by control of fire and loss of historic patterns of burning has altered the vegetation of the landscape, causing current climatic disturbances to be accentuated in their destruction. Flood events on tributaries appear to becoming more catastrophic rather than less, in spite of more flood control structures within the river systems. Peak river flow regimes appear to be moving earlier in the seasons, which may be affecting the quality of coho migration and rearing areas. The management of reservoirs, and practices for release of supplemental flows may be used to improve summer habitat rearing conditions. The effects of these patterns need further study.

Riparian quality and water quality within the watersheds have degraded from historic conditions, but probably are in an upward trend of recovery. Considerable action has been undertaken toward improvement of riparian areas in the basins, but much more needs to be done. More protection for riparian buffer zones and improved management to foster environmental diversity and complexity in riparian zones are essential needs.

Historic coho habitat elements, such as stream sinuosity, side channels, alcoves, wetland connections, etc. have been measurably reduced or eliminated through programs promoting channelization, bank stabilization, and filling for development. Maintenance of these critical habitat features has been impacted by flood control measures, in a convoluted effort to remedy problems from disturbances. These measures have also precluded the creation of new habitat areas.

Most of the ideal coho habitat occurs in the low gradient valley areas, which were also the most popular areas for development. Because of extensive human development, these areas will be the most difficult to access and restore.

Push up dams, while generally not adversely affecting coho propagation, have disturbed stream structure, water quality, and occasional redds. They may affect juvenile migration, and the timing of smolt out-migration. Practices of water diversion and water use should be evaluated for their effects upon salmonid production and water conservation programs encouraged. Water pollution is declining within the subbasins, but considerably more needs to be done, particularly non-point surface water drainage and control.

These long-term trends direct the need for prioritizing restoration actions and for considering the time dimension of recovery. The most critical actions for the Rogue Basin revolve around buffering and protecting riparian areas to allow naturalistic regeneration, and protecting/increasing in-stream flows in habitat areas. Other problems tend to be site specific in need. The South Coast problems tend to revolve around the effects of high winter flows, which affect stream structure (large woody debris and boulders) and sediment density.

Return to top of page.

Section C: HISTORIC FACTORS AFFECTING COHO
PRODUCTION, AND CURRENT LIFE-CYCLE NEEDS.

Step 2. Identify Historic Fish Management Practices,
Environmental Conditions and Their Effect
Upon Coho Production. Current Coho
Life-Cycle Habitat Needs Within the Rogue
and South Coast Basins.

Abstract: The current coho population is a product of past environmental and hatchery management actions, and their history is pertinent to planning restoration actions. There are specific habitat needs at the respective coho life cycle stages which must be met to stabilize and enhance population growth.

This section describes the historical fish management practice, and life cycle habitat needs in the Rogue and South Coast basins.

C.1. Historic Salmon Populations. Since the turn of the century, major environmental changes and habitat degradation have negatively impacted salmonid populations in the South Coast and Rogue basins. Run size estimates at Gold Ray Dam show significant declines in returns of coho salmon (ODFW, 1991a), winter steelhead (ODFW, 1990) summer steelhead (ODFW, 1994) and spring chinook salmon (ODFW unpublished data) from the time the counting station was first operated in 1942 through the late 1960s. Some believe we are now witnessing a death spiral of these salmon populations. Others believe this decline is just a phase of a rising and falling population cycle. Historic populations have not been known to decline to the recent low numbers observed in southwestern Oregon, however.

Historically, Indian Tribes harvested fish for consumptive use and developed annual rituals around their harvest, but had relatively little impact upon total fish production⁽³⁸⁾. Estimates of Indian consumption of fish in the Rogue Basin range up to 0.9 million pounds/year (all species)⁽³⁹⁾. Commercial fish harvest was conducted for over a century, harvesting some 1.4 million pounds/year (salmonid species).⁽⁴⁰⁾ Early settlers and miners harvested large quantities of fish and sold fish for alternative income, hauling wagon loads of fish to distant urban centers. Commercial canneries operated at the mouth of the Rogue and coastal rivers beginning in 1877, and continued for several decades until the canned fish market atrophied in the 1930s, and catch populations continued to decline to the 1960s. Salmonid populations have fluctuated widely since these first recorded times, with the Rogue cannery catch ranging from 28,000 fish in 1877 to 86,000 in 1891. The detrimental effects from mining, damming, logging, irrigation diversions, and forest harvest practices and early commercial river harvest combined, depressed the population, but did not bring them to threatened status until the emergence of increased commercial ocean harvest in the late 1960s. By the 1970s coho stocks were threatened, with escapement level counts to the Rogue Basin ranging below 500 fish.

Sheppard estimates that North American salmonid abundance remained relatively constant

from the 1890s through the 1960s⁽⁴¹⁾

(early fishery biologists sometimes combined fish species in estimating abundance, instead of estimating single species).

Light, in 1987, attempted to estimate total steelhead runs for the Northwest coast for the 1980s, based upon sport harvest data, dam counts, and other river counts. He estimated wild Oregon coast runs approximating 108,000 fish in the mid-1980s (a figure that approximates Sheppard's estimate in the 1970s)⁽⁴²⁾. Although these estimates tell us little about the southwest Oregon coho population, they do provide a vision of the likely metapopulation size.

C.2. Hatchery Influences. Fishery managers have altered the genetic composition and propagation of salmonids in the Rogue Basin since 1875. Anecdotal information and records collected by Cole Rivers indicate that cannery managers released up to 250,000 chinook in 1880, and moved the fry from stream to stream along the Coast to repopulate 'depleted' streams.⁽⁴³⁾ In 1904, over 8 million hatchery salmon were released in the Rogue River system and 18 million released in 1924,⁽⁴⁴⁾, with hatchery managers operating on the principle of 'The more fish, the better'. Salmonid eggs were transported (and no-doubt imported) to and from streams all over Oregon, Washington, and Northern California through several decades, until the practice was limited through state legislation in 1931 to protect native fish populations in streams.

Busby, 1994, in analyzing DNA from Western Oregon salmonids, notes that there is considerable consistency in southwestern Oregon DNA composition with fish populations in northern Oregon and Columbia basin stocks having much more similarity than would be expected. Perhaps this finding is reflecting the effects from the practices of fish managers a century ago in creating genetic homogenization within fish species from multiple river systems throughout the west coast⁽⁴⁵⁾.

Nonresident fish species have been added to the river system several times throughout the past century by businessmen and U.S. Bureau of Fisheries, with most species not surviving. Hatchery managers reported in 1877 that several penned stocks were infected with slimy fungus (probably Saprolegnia sp.), thus disease and parasites were added to native stocks over a century ago.

Wild Stock Supplementation from Hatchery Production. For several years, concern has been expressed about dilution of the wild stock gene pool through interbreeding hatchery and wild stocks. An unknown portion of hatchery stock interbreed with wild fish, and spawn in the wild environment. There is some evidence that interbred hatchery stock have lower levels of survivability than full native stock (some estimates are as low as 10%⁽⁴⁶⁾), but the extent of behavioral change and genetic migration is still unknown. Some local fishery biologists think that hatchery supplementation may have provided critical brood stock for seeding underutilized habitat areas in the Rogue Basin when the Cole Rivers Hatchery went into production in 1976, but the extent of this impact is not known.

The CSRI Technical Team has recommended a new hatchery operations policy for coho hatcheries, with production to be limited to supporting seeding of underutilized habitat areas⁽⁴⁷⁾. This policy will be reviewed by the ODFW Commission, and state legislature. Any final policy will need to be consistent with the ODFW Wild Fish Management Policy, which stipulates that no more than 50% of the natural spawning population may be hatchery stock.

C. 3. Rogue Basin Coho Production.

The Rogue basin is on the southern end of the coho range in Oregon. Coho are the least abundant wild salmonid (with the exception of sea-run cutthroat) that use the Rogue system, but historically, the Rogue was a substantial producer of coho. Commercial harvests of coho began in 1861 and by 1888 the Rogue River fishery ranked third among the fisheries of the West Coast. In the early 1900s, egg-taking stations were operated by both public and private interests on a number of Rogue tributaries including the Applegate River, despite concerns as early as 1911 that salmon fish runs in the Rogue were declining [It should be noted that the cannery harvested all salmonid species, and probably did not make any particular effort to distinguish among species, so harvest numbers may be distorted]. Between 1976 and 1989 the freshwater escapement of coho into the Rogue River basin was estimated at 7,000 hatchery and wild adults. The present estimate is approximately 3,600 hatchery and 3,200 wild age three adults .⁽⁴⁸⁾

Adult coho enter the Rogue River system beginning in September. The upper river stocks reach Gold Ray Dam around mid-October, and hold in the main river until rains allow them to move into the secondary streams and tributaries to spawn in December and January (see Table 2 below). The lower river runs actually enter the river a little later but still spawn around the same time. During large run years, spawning may continue into March. Fry emerge during the month of April and rear in lower mainstems of streams for a year until they smolt. Smolts migrate to the lower mainstem Rogue River from mid-May through July. Young coho winter over in large pools and backwaters which provide cover during high water months. Most Rogue coho spend a year in freshwater and two years at sea before returning to their home stream to spawn. A small percentage of the population spend less than a year in the ocean before maturing as age 2 jacks.

Table 2. Coho Life-Cycle Model for the Rogue basin

Stage

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sept

Adult Migration

X

X

X

Adult Spawning

X

X

X

Eggs/Fry Emerge

X

X

X

X

Fingerlings/Rearing

X

X

X

X

X

X

X

X

X

X

X

X

Juvenile migration

X

X

X

X

X

Smolt out migration

X

X

X

X

X - Indicates presence at the life-cycle month stage.

Besides coho, the Rogue Basin contains fall and spring chinook, winter and summer steelhead, and resident rainbow and cutthroat trout (including a small sea-run cutthroat trout population below the Illinois River). Brook and brown trout have also been introduced into the upper reaches of the basin. The Oregon Department of Fish and Wildlife manages the river system for multiple species. Data on coho smolt production of core areas and other coho habitat areas are very limited and need to be expanded.

C.4. South Coast Coho Production.

The South Coast basin area includes five rivers, ten creeks, and smaller watersheds that empty directly into the Pacific Ocean along 100 miles of coastline. The watershed is located in the southwest corner of Oregon, in Curry and Coos Counties, within the Klamath Mountain physiographic region. The watershed is approximately 1,100 square miles, following the coastal crest, which extends inland up to 30 miles, and north from the California border to the Coquille River Basin. It does not include the Rogue or Coquille Rivers. Since this report deals exclusively with the Klamath Mountain Province, it essentially does not include any streams north of Cape Blanco.

Habitat is limited by the steep gradient of streams originating in the Siskiyou Mountains. In the upper, forested parts of the basin the steep gradient, high winter flows, and the transitory nature of large wood limit overwintering habitat. Lower in the system, sediment becomes a problem in some areas. Historically, the available overwintering habitat was probably concentrated in the mainstem and tributaries of the lower 3 to 5 miles of the watersheds where the open valleys and relatively unconfined channels provided side channels, backwaters, and ponds during high winter flows. That type of habitat is now very limited in most of the South Coast streams.

The South Coast Basin is on the southern end of the coho range in Oregon. Coho are the least abundant wild salmonid, with the exception of sea-run cutthroat trout, that use this area. The most significant population exists in the Floras Creek River system, which is just north of the Klamath Province. The Sixes, Elk, Winchuck and Chetco Rivers contain small populations of coho but in some of these streams there may be just remnant populations or strays attempting to colonize underutilized habitat.

Commercial fishing on the southern Oregon coast began in the early 1860s with the construction of canneries and hatcheries. By the mid-1900s a fleet of 60-70 fishing vessels operated out of Port Orford. Salmon harvest since the turn of the century has focused on offshore runs dominated by coho. According to commercial catch records during the 1927-28 season, for example, 13,336 pounds of coho were taken from the fishery on Elk River. That poundage would be equal to approximately 1,500 coho. As stocks throughout the basin have declined, the commercial fishery for coho has been closed.

Although coho numbers in the South Coast basin were never great, fish were distributed in almost every stream. The spatial distribution of coho is relatively unchanged from historic use areas, but current production has declined substantially from historic levels.

Adult coho enter South Coast basin streams beginning in September and hold in the estuary and lower river holes until rains allow them to move upstream to preferred spawning areas on the mainstem and in tributaries (see Table 3). Spawning occurs in December and January. Fry begin to emerge in March and April, and they rear in the backwaters and pools of the lower reaches for a year. Juveniles smolt in the spring and move into the ocean from May through July. Almost all coastal coho spend a year in freshwater and two years at sea before returning to their home stream to spawn.

Table 3. Coho Life-Cycle Model for the South Coast Basin .

Life-Cycle Stage

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sept

Adult Migration

X

X

X

X

Adult Spawning

X

X

X

Eggs/Fry Emerge

X

X

Fingerlings/Rearing

X

X

X

X

X

X

X

X

X

X

X

X

Juvenile migration

X

X

X

X

X

Smolt out migration

X

X

X

X

X - Indicates presence at the life-cycle month stage.

Besides coho, the South Coast Basin contains fall chinook, winter steelhead and sea-run and resident cutthroat trout. Data on coho smolt production of core areas and other coho habitat are very limited and need to be expanded.

C.5. Summary.

This analysis has examined basin-wide effects of environmental conditions upon coho habitat and propagation in the Rogue and South Coast Basins and identified life cycle habitat requirements and concerns to be addressed in preparing recovery actions. The life cycle model identifies habitat needs at specific time periods and limiting factors that must be addressed to stabilize coho production.

Section F of this document focuses upon specific core habitat areas and identifies limiting factors that need to be linked to life cycle habitat needs in restoration actions.

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Section D: NATIVE COHO POPULATION VARIABILITY

Step 3: Establish A Minimum Viable Coho Population Size.

Abstract: This section examines natural coho population variability for the Southwest Oregon region, and establishes a population range that is considered necessary to maintain minimum genetic integrity. This range is the basis for establishing the measures that the Southwest Oregon Initiative will use to stabilize the coho population in southwest Oregon from further decline.

This section also estimates an average population size necessary to account for natural fluctuations that will ensure the native coho population will not drop below the minimum level necessary to maintain its genetic integrity.

D. 1. Coho Population Variability.

D.1.a. Concept of Population Variability.

It is axiomatic among ecologists that there is a natural range of variability in nature, and environmental conditions are better portrayed by the trend of change than by any singular data- point in time. Ecologists observed that the "Range of Natural Conditions" is reflected more by the patterns across environmental events, than by the data points or extremes themselves. Thus, the patterns represented within a data set are more revealing than any single indicated environmental condition. This concept of natural variability provides a means through which we estimate population numbers necessary to stabilize the coho population at minimum viable levels.

This concept of change was demonstrated for southwest Oregon in 1991, when federal ecologists for the Siskiyou, Rogue, and Umpqua National Forests sought to conduct an "ecosystem assessment" of environmental conditions in the Klamath Mountains Province.⁽⁴⁹⁾ They noted that an enduring problem is that environmental data often indicate a wide range of variability in conditions that individually may be presumed to be abnormal. It often is unclear whether a catastrophic event (such as a flood, drought, or large drop in population numbers) is a harbinger of change, or is simply an expected event within natural environmental cycles. Thus if a range of known indicators are summed to represent a trend, it is possible to develop summary indicators of ecosystem health. For example, if a majority of range points are evenly or randomly distributed within the natural range of environmental conditions, an ecosystem may be judged as representing natural variability, and no general state of "unhealthiness" may be indicated; if however, the majority of range points tend to reflect stressed or extreme conditions, an unhealthy condition may be indicated for a targeted species. Thus, populations must be managed for variability within naturally occurring ranges, both within the genetic variation of a species, and in overall population size. The difficulty lies in establishing the natural range of an environmental phenomena, and in assessing whether an extreme event is actually outside the normal range of variability, or within poorly defined margins of normality.⁽⁵⁰⁾

D.1.b. Stabilizing the population.

The native coho population in southwest Oregon varies considerably in numbers from year to year, varying up to 400%. If the population is stabilized with a positive trend, we can be reasonably safe in maintaining a minimum genetically viable native coho population. Through identifying the natural range in population numbers and its historic lower limit, we can establish a minimum escapement level for the basin that should not be exceeded. That level could also serve as a baseline to monitor future progress toward a recovery in the population.

D.2. Coho Population Variability within the Southwest Oregon ESU.

This section applies a concept outlined in the NMFS Status Report to describe as precisely as possible the conditions affecting variability of the coho population within the Oregon side of the Klamath Mountains Province Evolutionarily Significant Unit (ESU); i.e. - our geographic production area.⁽⁵¹⁾ The process compares the current population of coho with the range of natural variability (using best available data). If population numbers trend downward, and/or are consistently below the natural range of variability, then the population should be judged "in jeopardy." Ideally, this analysis would be conducted both within and across watersheds to identify problem areas, as well as judge the overall condition within the range of coho production in southwest Oregon.

There is no single preferred method in the literature for estimating or establishing the essential natural range of a coho population, therefore, a strategy of formulating successive approximations from three models was used. Since South Coast production follows similar cycles, and is linked to the Rogue Basin in being in the same ESU, the two basins are combined in this analysis. The Klamath Province South Coast coho production is estimated at generally less than 1% of Rogue Basin production, or about 200 adults/year.

D.2.a. Method 1: Historic Level of Survivability.

Estimates of historic runs for Oregon coastal salmon (south of the Columbia River, and north of California) range up to 1.6 million adults in the early 1900s, but in the last decade, the run may have declined to below 100,000 adults.⁽⁵²⁾ The Rogue and South Coast system may have represented between five and ten percent of west coast total salmon production.

Throughout the last half of this century, the Rogue Basin fishery has probably always functioned on the lower edge of the threshold of survivability. Actual levels of natural production in Southwest Oregon are difficult to estimate (see box below on problems of counting fish populations). In the 1890s the Rogue Basin supported an estimated 60,000 native coho, based upon estimates projected from cannery shipments. Between 1899 and 1936, Upper Rogue wild coho production was greatly overshadowed by privately operated hatcheries, which produced between 64,000 - 5,242,000 fingerlings/year. Thus, there is no reliable or accurate estimate of wild coho production for this period.

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ESTIMATING COHO PRODUCTION

Determining the coho population in the Rogue and South Coast basins is a difficult process, subject to various inaccuracies. Counting fish is an expensive process, requiring considerable labor and time over an extended period. There are difficulties in determining the species, counting mixed-age groups, and working in turbid waters. Further, fish don't stay put, but migrate into and out of river systems, sometimes travel at night, or may be flushed somewhere by flood flows. For reasons unknown to fish biologists, they may avoid some streams and tributaries some years, then flock to them at other times. Counting actions may include all fish at one point or time, then only wild fish at another point. Different counting techniques can yield different results, depending upon the month, stream characteristics, persons doing the counting, time of day, and other unknown factors.

Fish populations are often estimated for a particular stream, based upon counts at some other location (such as Huntley Park, Gold Ray Dam, or Cole Rivers Hatchery). For example, if the number of hatchery stock returning to the hatchery are high, then estimates for other river systems are also projected at higher levels. It is impossible, under current practices, to know if the escapement population for a given stream is normal, high, or low, since there is little baseline data to compare. ODFW conducts most counting operations, but funding is extremely limited for population monitoring, so the Department must resort to estimation procedures.

The ODFW operates fish counting stations on the Rogue River at Huntley Park and Gold Ray Dam. ODFW also monitors hatchery coho returns to the Cole Rivers Hatchery.

Huntley Park is located on the south bank of the Rogue River at River Mile 7. ODFW began this inventory program in 1976 to monitor the summer steelhead population. However, they also collect fall chinook and coho in adequate numbers to make a reasonable population estimate when conditions are suitable. The deep pool at Huntley Park is seined 15 times a day, 3-4 days each week from July through October when river conditions no longer make seining practical. Coho still enter the river after the seining effort has ceased but enough data is usually collected to statistically estimate the total run size with the Gold Ray Dam counts and Cole Rivers Hatchery returns factored in.

Gold Ray Dam is located just above the town of Gold Hill at River Mile 126. The counts began in 1942 by counting fish passing over a white board in the ladder channel. A few years later an underwater viewing window was installed. The counter tallied fish passing the window eight hours a day, three days a week and the total count was statistically estimated. In the late 1980s it was noted that coho returns to Cole Rivers hatchery were higher than the projected counts over Gold Ray Dam. It was suspected that some of the coho were passing Gold Ray at night. In 1991 a video camera was installed that records every fish passing the window 24 hours a day, seven days a week. Since 1992 all of the 200,000 coho released from Cole Rivers Hatchery have been physically marked. Consequently, all coho passing the dam are counted, with the numbers of hatchery and wild fish accurately recorded.

Most of the adult coho returning to the upper Rogue , enter the hatchery, located at River Mile 157, and are stripped of their eggs. About 98 percent of the coho are of hatchery origin. The few wild fish collected at Cole Rivers Hatchery are also spawned and used in improving the genetic composition of the hatchery stock. All returning coho are hand counted and examined for marks. The percentage of hatchery and wild fish is compared with the counts at Huntley Park and Gold Ray Dam. These data help develop a coho population estimate for the entire basin.

In other instances salmonid monitoring is conducted at specific locations by electroshocking pools and counting fish, seining to count fry, snorkeling, installing trap boxes, visual counting, and sportsman catch reports. Escapement rates for specific streams is often based upon redd counts or carcass counts after spawning. Many of the carcasses are consumed by animals, rot, or are not visible. Samples may be taken at different months at different locations, and virtually

no systematic on-going sampling is done other than at Huntley Park, Gold Ray Dam, and Cole Rivers Fish Hatchery.

Until very recently, hatchery fish were not marked, and all counts were combined total counts. In 1992, marking was commenced, and now all hatchery stock are marked before release. Thus, considerable error must be associated with early population estimates before 1994.

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From 1936 to 1976 there also was transport of coho stocks both out of and into the Rogue Basin. Out-of-basin stocks were planted in the Rogue system in 1957 (50,210 - Coos stock fry) and again in 1966, 1968, 1969, and 1971 (950 Alsea stock fry).⁽⁵³⁾ Coho eggs were regularly transported in large quantity out of the region (tens of millions of eggs) during four to five decades (particularly before the 1940s).⁽⁵⁴⁾ The extent of removal was so great that the State legislature finally limited egg export to 40% of local escapement, and this law (developed because of excessive coho egg transport out of the Rogue Basin) still applies state-wide today.

The best data on historical native coho population in the Rogue Basin during this century is during the period between 1936 and 1976. Hatchery production during this period was sporadic and consisted primarily of fry releases into the mainstem by state hatcheries.⁽⁵⁵⁾ Subsequent studies have found that survival of unfed fry into the mainstem was minimal. Since the releases

were well below Gold Ray Dam, there was virtually no impact on the fish counts at Gold Ray, which started in 1942. During this period, natural production ranged from a high of 10,000 natives to a low of 200 adults/year (see Figures 5 and 6 below). The production trend line for this period is clearly declining, reaching fewer than 500 adults/year between 1964 and 1978.

The sampling of Rogue River Basin fish populations between 1980 and the present primarily was undertaken in two locations: Huntley Park in the lower Rogue and Gold Ray Dam near the entry into the Upper Rogue drainage.

Figure 5 presents the calculated wild returns since sampling began at Huntley Park in 1979. Fish counts at Huntley Park since 1979 (through 1996) for native coho production in southwest Oregon ranged between a low of about 174 fish to a maximum of about 9,757. The average over the 18 years was about 3,630 wild coho.⁽⁵⁶⁾ [Note: The accuracy of these counts may underestimate total production in the Rogue System due to the sampling method used.]

Figure 6 displays the calculated wild fish returns for Gold Ray Dam. During the period of 1979 to 1995, counts of wild fish passing Gold Ray indicate a low of 195 fish to maximum of 3,681 fish. [Fish counts for Gold Ray Dam for 1996 have not been compiled at this printing, but early indications from Huntley Park indicate a stronger run than 1995.] During this same period the return of hatchery fish over Gold Ray Dam showed much greater fluctuations in population. Counts of hatchery coho showed a range of about 485 hatchery coho to a maximum of 10,173 fish. Hatchery releases during this period were held essentially constant at about 200,000 coho smolts annually. Because of this year to year consistency in the numbers of coho smolts released, it can be conjectured that the variation in the return of these adult hatchery fish is primarily related to oceanic conditions.

If we consider that both the wild and the hatchery coho are being subjected to the same oceanic conditions then we would expect that both populations would tend to peak and bottom out in similar proportions to their relative smolt populations. This is not the case based on the above data and the information contained in Figures 5 and 6. What can be seen is that the wild fish are bottoming out in a similar fashion as the hatchry fish when oceanic conditions are poor but they are not peaking at the higher levels as we would expect when oceanic conditions seem to have improved. Instead, for this time period, the wild coho never seem to exceed a total upper Rogue estimated population of 4,000. In fact the figures indicate the coho population "flatlines" within this range. The main explanation would seem to be that the wild fish are not leaving the freshwater areas in numbers sufficient to allow for a greater return. Hatchery fish, which are not subjected to the stresses of freshwater rearing are not limited by the carrying capacity of the freshwater habitat in the Rogue River while the wild coho are limited by the natural habitat conditions.

Figure 5 - Huntley Park data

Figure 6 - Gold Ray Dam data

Based on our assessment, focusing on improving freshwater habitat could potentially be the most productive and important fishery management steps that can be taken to improve wild fish production in the Rogue Basin. The good news is that the Rogue coho stocks appear to have a high degree of rebound capacity, in that production can and has rebounded from very low threshold populations within this century. Since 1978, the production pattern has been trending upward. The lower limit of 124 adult escapement is believed to be at a level which greatly threatened genetic survivability of the species⁽⁵⁷⁾. Using the information collected on natural variability, we see that an average of 3,600 adults resulted in this lower limit occurring within the production cycle, which means that we should establish an average production target somewhat greater than the 3,600 level in order to ensure long-term survivability. As an example, a target range of three times this number, an average of 10,800 adults/year, would be expected to better protect the genetic viability of the population over time (which might produce a lower limit of approximately 1,000 adults/year in low production years).

D.2.b. Method 2: Ricker Stock-Recruitment Model.

The Ricker Stock-Recruitment model estimates the population necessary to achieve the "maximum" recruitment for the Rogue Basin. Under "good" conditions, about 3,000 native adults could potentially achieve "maximum" recruitment which would result in the production of about 8,000 aged-three adults for the next generation returning three years later⁽⁵⁸⁾ The 8,000 level of production, if maintained as an average returning adult population, could be expected to fluctuate to as low as 3,000 in "poor" years, which is considered to be at the lower edge of genetic survivability. Therefore, an 8,000 population of returning and successfully spawning adults could be used as a target for setting a minimum average population which under normal population fluctuation conditions would not fall below a 3,000 level of minimum genetic viability.

Figure 7: TYPICAL COHO SURVIVAL RATES

One pair of Coho Adults

Produces between 1,000-5,000 eggs
(Average about 2,500 eggs)

Between 20 - 60 % of eggs hatch
and survive to fry stage
( Average about 30%)

About 80% of fry survive to smolt stage
and migrate to the ocean

Between 1 - 10% of smolts will survive
the ocean environment, and return to
spawn (Average 2.5%).

Spawner recruitment rate for the Rogue
Basin is about 6.6% (in good years),

Each generation of adult-pairs produce
0 .5 - 16 fish for the next generation.