Pacific salmon (Oncorhynchus spp.) runs in rivers that flow into the eastern Bering Sea have been inconsistent and at times very weak. Low returns of chinook (O. tshawytscha) and chum (O. keta) salmon to the Yukon River, Kuskokwim River, and Norton Sound areas of Alaska prompted the state of Alaska to restrict commercial and subsistence fisheries during 2000 and declare the region a fisheries disaster area. Weak salmon returns to these river systems follow several years of low sockeye (O. nerka) salmon returns to Bristol Bay, which was declared a fisheries disaster region during 1998 by both the State of Alaska and the U.S. Department of Commerce. Causes of the poor salmon returns to these river systems are not known however, the regional-scale decline of these stocks indicates that the marine environment may play a critical role. Ocean conditions, particularly in the first few months after the salmon leave fresh water, are known to significantly affect salmon survival (Holtby et al. 1990; Friedland et al. 1996; Beamish and Mahnken 2001). Mechanisms affecting marine survival of the eastern Bering Sea salmon stocks are unknown, principally due to the lack of marine life history information on western Alaska salmon. To improve understanding of the marine life-history stage of salmon in the Bering Sea, the North Pacific Anadromous Fish Commission (NPAFC) began an internationally coordinated research program on salmon in the Bering Sea called the Bering-Aleutian Salmon International Survey (BASIS) (NPAFC 2001). As part of BASIS, scientists from the National Marine Fisheries Service (NMFS), Ocean Carrying Capacity (OCC) program conducted a fall survey on the eastern Bering Sea shelf to provide key ecological data for eastern Bering Sea salmon stocks during their juvenile life-history stage. The goal of the OCC/BASIS salmon research cruise was to understand mechanisms underlying the effects of environment on distribution, migration, and growth of juvenile salmon on the eastern Bering Sea shelf. Primary objectives of BASIS include: 1) to determine the extent of offshore migrations of juvenile salmon from rivers draining into the eastern Bering Sea, 2) to describe the physical environment of the eastern and northeastern Bering Sea shelf occupied by juvenile salmon, and 3) to collect biological information on other ecologically important species. Summaries of previous Bering Sea juvenile salmon research cruises can be found in Farley et al. (1999, 2000, 2001, 2002, 2004, 2005).

The project consisted of a nearshore fish, invertebrate, and habitat survey in northern Bristol Bay, Alaska. A 32-ft. gillnet vessel, the F/V Willow was chartered for the survey, and we also used a 20-ft. aluminum skiff with 90-hp. motor for shallow water work. The survey was staged out of Dillingham, Alaska and took place from July 26-August 8, 2009.The main gear types used during the survey were a beach seine and a bottom beam trawl. A surface pair trawl (towed by the vessel and the skiff) was deployed in one location. Using these gear types, we sampled from the shoreline to 17 m depth, as well as surface waters ~1 km from the shoreline. Catches were sorted to species, enumerated, and when possible weighed using spring scales. Length measurements were taken for most species. Voucher specimens were preserved in 10% formalin for confirmation of species identification. A small number of samples were frozen for age and energetics analysis . Photographs were taken of most species. Small, datalogging conductivity-temperature-depth recorders (CTDs) were deployed on the trawl gear, and also placed on temporary moorings in several locations to study fluctuations in temperature and salinity over tidal cycles. We also recorded habitat variables at beach seine sites according to the methodology used in the Nearshore Fish Atlas of Alaska. During July 26-August 1, 2009 sampling was conducted in Nushagak Bay. High wind and waves hampered the sampling throughout this entire week and largely determined possible sampling locations. Two days were completely lost due to weather. On August 3 we traveled from Dillingham to the west side of the Nushagak and from August 4-8 sampling was conducted along the Nushagak Peninsula and in Kulukak, Nunavachak, Ungalikthluk, and Togiak Bays. During most of this time we experienced high winds but they did not hamper the sampling to the same degree as in the Nushagak. On August 8 we traveled back to Dillingham.

The Arctic region has experienced warming in recent years, resulting in decreased summer sea ice cover and increased sea surface temperatures. In 2007, the U.S. BASIS survey extended surface trawling into the Chukchi Sea; juvenile chum salmon were collected at most stations. Genetic methods were applied to identify the origin of the juvenile chum salmon collected in the Chukchi Sea and Bering Strait. Most of the juvenile chum salmon caught in the Bering Strait were from northern Russian populations and the majority collected in the Chukchi Sea were from northwestern Alaska populations.

A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2005 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was undertaken to determine the overall stock composition of the sample set. Samples were genotyped for eleven microsatellite markers and results were estimated using the current chum salmon microsatellite baseline. In 2005, genetic samples were collected opportunistically as part of a special project and supplemented with archived scales from the Observer Program. Sample biases have the potential to affect stock composition analysis results; consequently, stock composition estimates apply to the sample set and may not represent the entire chum salmon bycatch. Based on the analysis of 1,084 chum salmon bycatch samples collected throughout the 2005 Bering Sea trawl fishery, East Asian (29%), North Asian (29%), Pacific Northwest (19%) and Western Alaska (16%) stocks dominated the sample set with smaller contributions from Southwest Alaska (<2%) and the Upper/Middle Yukon River (5%) stocks. The estimates for the 2005 chum salmon bycatch sample set were similar to the 1994-1995 chum salmon bycatch estimates, suggesting consistency of the regional stock contributions across years. Analysis of temporal groupings within the groundfish B season revealed changes in stock composition during the course of the season. Whether the decreasing proportional contributions of Western Alaska and Upper/Middle Yukon stocks and increasing proportional contributions from Asia over time are due to temporal or spatial differences in the sample set are unknown.

This study is a cooperative effort between Douglas Island Pink & Chum (DIPAC), the University of Alaska Fairbanks, School of Fisheries and Ocean Sciences (UAF, SFOS), the National Oceanic & Atmospheric Administration, Auke Bay Lab (ABL), and the Alaska Department of Fish & Game (ADF&G) to determine the potential for interactions between DIPAC hatchery chum salmon (Oncorhynchus keta) fry and wild chum salmon fry in Taku Inlet, Southeast Alaska. We analyzed patterns in spatial and temporal distribution, size, and condition of juvenile chum salmon collected in the littoral and neritic waters of Taku Inlet in 2004 and 2005. Energy density and diet of wild and hatchery chum salmon fry in Taku Inlet were analyzed and compared to data obtained later in the season for chum salmon stocks caught in Icy Strait. The greatest potential for wild/hatchery interactions was in the outer inlet, directly following early hatchery releases (May 9-11). Peak outmigration for wild chum salmon fry coincided with early hatchery releases; in contrast, most wild chum salmon fry had already emigrated from the estuary by the time of late hatchery fry release (May 22 June 1). In both years, hatchery fry were rare in the inner inlet, but comprised over 95% of the catch in the outer estuary during the peak of outmigration. Hatchery chum salmon were significantly larger than wild fry in both beach and neritic samples. Wild and early hatchery chum salmon were smaller in the littoral than the neritic habitat, indicating that both groups moved from shallow to deeper water with ontogeny. In spite of large differences in abundance, no negative correlation between abundance of hatchery fish and condition of wild fish was identified. Both wild and early hatchery chum salmon fry showed apparent growth through the season, while late hatchery fry appeared to leave the estuary soon after release. Regardless of origin, most chum salmon juveniles emigrated from the study area in late May and early June, indicating a high probability for mixed-stock schools. Hatchery chum salmon juveniles were initially larger and had greater energy content than wild fish; however, energetic values converged by mid-June in Taku Inlet. In Icy Strait, energetic condition of wild and hatchery chum salmon juveniles was also similar. Multivariate analysis of 54 prey measures indicated that diets of the two groups were distinctly different throughout the season in all Taku Inlet locations and converged in Icy Strait.

Diel epipelagic sampling for juvenile Pacific salmon (Oncorhynchus spp.), rockfish (Sebastes spp.), sablefish (Anoplopoma fimbria), and associated species was conducted in order to identify factors that may affect year-class success of these commercially important species. Sampling occurred in offshore marine habitats of the coastal northeast Pacific Ocean from 10-20 August 2005 and was conducted with a surface trawl fishing the upper 20 m of the water column along transects up to78 km offshore near 58 N. Three habitats were sampled along each transect over a 24-hr period: the continental shelf (<200 m depth), the continental slope (400-750 m depth), and the abyss (>2,000 m depth). A total of 38,747 fish and squid representing 24 species were sampled in 56 trawl hauls. Of the targeted juvenile fish species, a total of 587 salmon, 11 rockfish, and 70 sablefish were captured. Sampling during day (1500-1900) and night (2200-0200) periods indicated that biomass of fish and squid was 2-4 times higher at night at (each?)all habitat types pooled across transects. No distinct patterns between day or night occurrence were noted for juvenile pink salmon (O. gorbuscha), chum salmon (O. keta), sockeye salmon (O. nerka), or coho salmon (O. kisutch), however, juvenile Chinook salmon (O. tshawytscha) were encountered only at night. Catches of juvenile rockfish and juvenile sablefish were quite low in this study, and larger sample sizes of these fish are needed to adequately determine their diel distribution. Diel differences were apparent with forage species such as Pacific herring (Clupea pallasi), capelin (Mallotus villosus), and eulachon (Thaleichthys pacificus) that were almost exclusively sampled at night. The offshore distribution patterns of target species were distinctly different, with the most common occurrences of juvenile salmon over continental shelf habitats, juvenile sablefish over continental shelf and slope habitats, and juvenile rockfish over slope and abyss habitats. Pacific herring, capelin, eulachon, and Pacific sardines (Sardinops sagax) were found over continental shelf habitats, whereas small squid and myctophids occurred primarily at slope and abyssal habitats. The greatest overall catch biomass was of gelatinous species (jellyfish), which was consistently higher than that of all fish and squid combined, usually by an order of magnitude. Individual fish or squid species with highest average weight per haul were pomfret (Brama japonica), adult coho salmon, Humboldt squid (Dosidicus gigas), and blue sharks (Prionace glauca). The occurrence of the latter two warm-water species and Pacific sardines were of interest because this study occurred during an anomalously warm year and the capture of Pacific sardines and Humboldt squid represent northern range extensions for these species. Stomach content analysis of potential predator species of the target species showed that only adult coho salmon were predating on juvenile salmon and sablefish, and only pomfret were predating on juvenile rockfish. Further sampling of the target species is needed in these habitats during more normal environmental conditions to validate these observations.

Chum salmon populations from across their geographic distribution have been analyzed with a set of SNP and microsatellite markers. As is typical for chum salmon populations, more genetic divergence was observed on larger geographic scales than on smaller regional scales. Strong divergence exists within and among the three regions of Asia, western Alaska, and the northeast Pacific. However, separation of coastal western Alaskan summer-run chum salmon populations, from Norton Sound to northern Bristol Bay remains problematic. The degree of divergence determines the spatial scale to which stock proportions of mixtures of chum salmon can be resolved. The baseline developed in this project will be used for mixture analyses to study the marine distribution of chum salmon populations in the Bering Sea. Scale and fin samples collected in the eastern Bering Sea will be used to determine whether the stock composition of chum salmon aggregations differ across areas, seasonally, and annually. Determining the stock distributions of these mixtures will provide information on the migratory pathways of chum salmon in the Bering Sea and the potential impact of bycatch of coastal western Alaskan chum salmon in the Bering Sea pollock fishery.

A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch from the 2012 Bering Sea walleye pollock (Gadus chalcogrammus) trawl fishery was undertaken to determine the overall stock composition of the sample set. A genetic analysis of chum salmon collected during a test of a salmon excluder device was also conducted. Samples were genotyped for 11 microsatellite markers and results were estimated using the current chum salmon microsatellite baseline. In 2012, genetic samples were collected systematically as part of a special project that commenced in 2011 to reduce sample biases that exist in collections from previous years and have the potential to affect stock composition analysis results. One genetic sample was collected for every 31.5 chum salmon caught in the 98% of the midwater trawl fishery that was sampled. Evaluation of sampling based on time, location, and vessel indicated that the genetic samples were representative of the total bycatch. Based on the analysis of 673 chum salmon bycatch samples collected throughout the 2012 Bering Sea trawl fishery, the North Asian stocks dominated the sample set (39%), with moderate contributions from East Asian (20%), Eastern Gulf of Alaska (GOA)/Pacific Northwest (PNW) (18%), and Western Alaska (14%) stocks, and smaller contributions from Upper/Middle Yukon River (7%) and Southwest Alaska (2%) stocks. The estimates for the 2012 chum salmon bycatch sample set differed from the mean of the 20052011 estimates for the two Asian regions, but not for the North American regions. The pattern of changes of regional stock contributions over three time periods in 2012 differed from previous years for some regions. There were some spatial differences in stock distribution; e.g., the East Asian stock contribution was higher in the central Bering Sea than in the southeastern Bering Sea. As with the bycatch samples, the salmon excluder device test samples included fish from all geographic regions despite being collected at small spatial and temporal scales.

A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch from the 2011 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was undertaken to determine the overall stock composition of the sample set. Samples were genotyped for 11 microsatellite markers and results were estimated using the current chum salmon microsatellite baseline. In 2011, genetic samples were collected systematically as part of a special project to reduce sample biases that exist in collections from previous years that have the potential to affect stock composition analysis results. One genetic sample was collected for every 31.1 chum salmon caught in 97% of the midwater trawl fishery that was sampled. Evaluation of sampling based on time, location, and vessel indicated that the genetic samples were representative of the total bycatch. Based on the analysis of 1,472 chum salmon bycatch samples collected throughout the 2011 Bering Sea trawl fishery, the Eastern Gulf of Alaska (GOA)/Pacific Northwest (PNW) stocks dominated the sample set (38%), with moderate contributions from East Asian (17%), North Asian (18%), and Western Alaska (16%) stocks, and smaller contributions from Upper/Middle Yukon River (9%) stocks. The estimates for the 2011 chum salmon bycatch sample set differed from the 20052010 estimates, indicating a change in the consistency of the regional stock contributions across the previous 6 years, possibly due to the larger proportion of bycatch caught later in the season and in the more southeastern NMFS reporting areas in 2011. There were significant spatial differences in stock distribution, with the Asian stocks dominating the central Bering Sea area and the Eastern GOA/PNW stocks dominating the southeastern Bering Sea. Analysis of temporal groupings revealed changes in stock composition during the course of the season with decreasing contribution of East Asia and Upper/Middle Yukon stocks and increasing contribution of Eastern GOA/PNW stocks over time.

FY20 will mark the 23nd year of sampling, making the Juvenile Salmon and Ocean Ecosystem Survey (JSOES) the longest running salmon survey on the west coast. JSOES has clearly demonstrated correlations between ocean conditions and the distribution, abundance, and survival of juvenile Columbia River (CR) salmon in the Northern California Current (NCC) nearshore ecosystem. For example, our ocean indicators provide managers from the federal and state governments, tribes, and other agencies/groups the ability to forecast adult returns one to two years in advance for coho and spring/summer Chinook salmon. We continue to show the importance of evaluating ocean conditions to support management decisions and to provide context for efforts by the Northwest Power and Conservation Council (NWPCC) and BPA to restore and enhance salmon production. The primary goal of our work is to develop a mechanistic understanding of how trophic dynamics and conditions in the ocean and CR plume affect survival of juvenile salmonids. This knowledge will allow us to improve forecasts in a quantitative rather than qualitative manner, and decouple the effects of mitigation efforts in the freshwater environment from the effects of a changing ocean environment. These improved forecasts will lead to well-informed recommendations for an ecosystem approach to management strategies based on the full suite of river, plume, and ocean environments. Stomach Contents from juvenile salmonids, primarily Chinook and Coho.