Search

Search Results

• 16321. [Article] A Proposal for an Integrated Research Monitoring Program for Oregon Coastal Chinook Populations

  Abstract -- Among the many chinook salmon populations contributing to large, mixed stock ocean net, troll, and recreational fisheries managed by the Pacific Salmon Commission (PSC) there is a good deal ...

  Citation × Citation Citation Abstract Copy Title: A Proposal for an Integrated Research Monitoring Program for Oregon Coastal Chinook Populations Abstract -- Among the many chinook salmon populations contributing to large, mixed stock ocean net, troll, and recreational fisheries managed by the Pacific Salmon Commission (PSC) there is a good deal of diversity with respect to productivity, life history characteristics, and ocean distribution. During the years immediately following the adoption of the original 1985 Pacific Salmon Treaty (PST), lack of adequate data prevented the PSC from managing effectively for these differences. Instead, chinook management outlined in Annex IV of the original treaty was based upon long term population trends for very large aggregates of stocks. Although harvest ceilings were established as part of a PST recovery plan for over-exploited stocks, they were based on average coast-wide production trends and resulted in over harvest of weak stocks in some years and failure to take advantage of large returns in other years. By the mid-l 990's, data relative to the distribution and abundance of many salmon stocks contributing to PST fisheries was improving. At the same time, there was increasing dissatisfaction with quota-based management and strong interest in instituting annual abundance-based management for stock aggregates that share geographic proximity of spawning areas, similar life history and genetic characteristics, and similar distributions in the ocean. Abundance-based management for aggregated stocks would establish and implement annual fishery exploitation rates in fisheries that insure long-term sustainability for all aggregates and related individual stocks. In the absence of bilateral agreement between the U.S. and Canada regarding implementation of abundance-based management, the three voting U.S. PSC Commissioners signed the 1996 Letter of Agreement (LOA) that defined elements of an abundance-based management approach for chinook salmon fisheries in southeast Alaska. The LOA was designed to: 1) set the stage for future bilateral negotiations regarding abundance based management; 2) clarify the role of PST fisheries in rebuilding depressed natural stocks; and 3) provide a means for sharing conservation responsibility of far-north migrating stocks originating from watersheds in Oregon and Washington. The foundation for abundance-based management set forth in the LOA was subsequently expanded upon and incorporated as Aggregate Abundance-Based Management (AABM) in Annex IV, Chapter 3 of the 1999 PST. Application of the abundance-based management outlined in the 1996 LOA and the subsequent 1999 amendments to the PST requires knowledge of the stock recruitment relationships, biological spawning escapement goals, and annual forecasts of ocean abundance and distribution for stocks in each aggregate to regulate fishery harvest. Managers must also have annual post-season estimates of aggregate specific exploitation rates and in-river escapements to assess the effectiveness of regulatory measures. The base-monitoring program for Oregon's coastal chinook under the 1985 PSC met only a few of these data requirements. In recognition of requirements for new and more precise data, the signatories of the original LOA sought out additional federal funds for new and expanded monitoring programs. Since 1997 Congress has annually approved approximately $1.8 million for additional research and monitoring needed to implement terms of the LOA. The PSC delegated discretionary authority for the use of those funds to the U.S. Section's Chinook Technical Committee (CTC). Title: A Proposal for an Integrated Research Monitoring Program for Oregon Coastal Chinook Populations Abstract -- Among the many chinook salmon populations contributing to large, mixed stock ocean net, troll, and recreational fisheries managed by the Pacific Salmon Commission (PSC) there is a good deal of diversity with respect to productivity, life history characteristics, and ocean distribution. During the years immediately following the adoption of the original 1985 Pacific Salmon Treaty (PST), lack of adequate data prevented the PSC from managing effectively for these differences. Instead, chinook management outlined in Annex IV of the original treaty was based upon long term population trends for very large aggregates of stocks. Although harvest ceilings were established as part of a PST recovery plan for over-exploited stocks, they were based on average coast-wide production trends and resulted in over harvest of weak stocks in some years and failure to take advantage of large returns in other years. By the mid-l 990's, data relative to the distribution and abundance of many salmon stocks contributing to PST fisheries was improving. At the same time, there was increasing dissatisfaction with quota-based management and strong interest in instituting annual abundance-based management for stock aggregates that share geographic proximity of spawning areas, similar life history and genetic characteristics, and similar distributions in the ocean. Abundance-based management for aggregated stocks would establish and implement annual fishery exploitation rates in fisheries that insure long-term sustainability for all aggregates and related individual stocks. In the absence of bilateral agreement between the U.S. and Canada regarding implementation of abundance-based management, the three voting U.S. PSC Commissioners signed the 1996 Letter of Agreement (LOA) that defined elements of an abundance-based management approach for chinook salmon fisheries in southeast Alaska. The LOA was designed to: 1) set the stage for future bilateral negotiations regarding abundance based management; 2) clarify the role of PST fisheries in rebuilding depressed natural stocks; and 3) provide a means for sharing conservation responsibility of far-north migrating stocks originating from watersheds in Oregon and Washington. The foundation for abundance-based management set forth in the LOA was subsequently expanded upon and incorporated as Aggregate Abundance-Based Management (AABM) in Annex IV, Chapter 3 of the 1999 PST. Application of the abundance-based management outlined in the 1996 LOA and the subsequent 1999 amendments to the PST requires knowledge of the stock recruitment relationships, biological spawning escapement goals, and annual forecasts of ocean abundance and distribution for stocks in each aggregate to regulate fishery harvest. Managers must also have annual post-season estimates of aggregate specific exploitation rates and in-river escapements to assess the effectiveness of regulatory measures. The base-monitoring program for Oregon's coastal chinook under the 1985 PSC met only a few of these data requirements. In recognition of requirements for new and more precise data, the signatories of the original LOA sought out additional federal funds for new and expanded monitoring programs. Since 1997 Congress has annually approved approximately $1.8 million for additional research and monitoring needed to implement terms of the LOA. The PSC delegated discretionary authority for the use of those funds to the U.S. Section's Chinook Technical Committee (CTC). Close

• 16322. [Article] Habitat use and activity patterns of Deacon Rockfish (Sebastes diaconus) at seasonal scales and in response to episodic hypoxia.

  Abstract -- Knowledge of fish movements and residency are key to design and interpretation of results from bioacoustic sonar and visual survey methods, which are being developed as tools for use in nearshore ...

  Citation × Citation Citation Abstract Copy Title: Habitat use and activity patterns of Deacon Rockfish (Sebastes diaconus) at seasonal scales and in response to episodic hypoxia. Abstract -- Knowledge of fish movements and residency are key to design and interpretation of results from bioacoustic sonar and visual survey methods, which are being developed as tools for use in nearshore rocky reef surveys to estimate biomass and species composition. Fishers in Oregon report that an important component of the nearshore catch, Deacon Rockfish (Sebastes diaconus), become unavailable to harvest seasonally, and suggest periodic migration away from nearshore reef areas. Seasonal and spatial variation in landings data potentially support this theory. We used a high-resolution acoustic telemetry array and a combination of presence/absence receiver arrays, to study the daily and seasonal movements and the activity patterns of 11 acoustically tagged Deacon Rockfish on a nearshore rocky reef off Seal Rock, Oregon. Over the 11-month study period, most fish (n=6) exhibited high site fidelity. For the duration of the high-resolution array (5 mo), these fish had small home ranges (mean 95% KDE=4907 m2) and consistent activity patterns, except during seasonal hypoxia (defined as dissolved oxygen concentration [DO] < 2 mg l-1). During the summer months, resident fish were strongly diurnal with high levels of daytime activity above the bottom in relatively rugose habitat, followed by nighttime rest periods in deeper water in habitat of relatively less rugosity. During hypoxia, fish exhibited moderate activity levels with no rest periods and moved well away from their core activity areas on long, erratic forays. Wintertime activity levels were moderate with less defined daily patterns, but fish continued to remain within the array area. We suggest that Deacon Rockfish remain on nearshore reefs throughout the year, but their visual capabilities and prey preferences for seasonally occurring planktonic organisms strongly influences their catchability. Habitat use and activity patterns exhibited by Deacon Rockfish are conducive to bioacoustic sonar and visual survey methods if season, daylight, and oxygen levels are considered. Title: Habitat use and activity patterns of Deacon Rockfish (Sebastes diaconus) at seasonal scales and in response to episodic hypoxia. Abstract -- Knowledge of fish movements and residency are key to design and interpretation of results from bioacoustic sonar and visual survey methods, which are being developed as tools for use in nearshore rocky reef surveys to estimate biomass and species composition. Fishers in Oregon report that an important component of the nearshore catch, Deacon Rockfish (Sebastes diaconus), become unavailable to harvest seasonally, and suggest periodic migration away from nearshore reef areas. Seasonal and spatial variation in landings data potentially support this theory. We used a high-resolution acoustic telemetry array and a combination of presence/absence receiver arrays, to study the daily and seasonal movements and the activity patterns of 11 acoustically tagged Deacon Rockfish on a nearshore rocky reef off Seal Rock, Oregon. Over the 11-month study period, most fish (n=6) exhibited high site fidelity. For the duration of the high-resolution array (5 mo), these fish had small home ranges (mean 95% KDE=4907 m2) and consistent activity patterns, except during seasonal hypoxia (defined as dissolved oxygen concentration [DO] < 2 mg l-1). During the summer months, resident fish were strongly diurnal with high levels of daytime activity above the bottom in relatively rugose habitat, followed by nighttime rest periods in deeper water in habitat of relatively less rugosity. During hypoxia, fish exhibited moderate activity levels with no rest periods and moved well away from their core activity areas on long, erratic forays. Wintertime activity levels were moderate with less defined daily patterns, but fish continued to remain within the array area. We suggest that Deacon Rockfish remain on nearshore reefs throughout the year, but their visual capabilities and prey preferences for seasonally occurring planktonic organisms strongly influences their catchability. Habitat use and activity patterns exhibited by Deacon Rockfish are conducive to bioacoustic sonar and visual survey methods if season, daylight, and oxygen levels are considered. Close