AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon
공공데이터포털
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).
AFSC/REFM: Nearshore fish survey in northern Bristol Bay, Alaska, July-August 2009
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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.
AFSC/RACE/GAP/Orr An annotated checklist of the marine macroinvertebrates of Alaska and a retrospective analysis of the groundfish trawl database.
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A comprehensive species list of marine invertebrates of Alaska has been lacking. The checklist of Austin (1985) treated the marine invertebrates of the southern coast of Alaska to California and since then many new species have been described, many range extensions have been discovered, and considerable changes in higher-level systematics have been made. The checklist we compiled lists over 3,500 species and includes the currently accepted scientific name and its significant synonyms, common names, type localities, geographic and depth distributions, a general statement of abundance in Alaska when known (e.g., rare, uncommon, common, abundant), and general remarks. This checklist will serve as a foundation for future species-specific research. Updated species lists are necessary to reflect the current state of biodiversity knowledge and are thus essential for conservation planning and management. To monitor and predict future changes to marine life, the distribution and abundance of marine species need to be better understood, and this can only be achieved with reliable identifications based on a sound taxonomy. The current status and future directions of Alaskan marine invertebrate biodiversity are briefly discussed.
AFSC/ABL: 2005 Chum Salmon Bycatch Sample Analysis Bering Sea
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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.
AFSC/ABL: Eastern Bering Sea (BASIS) Coastal Research on Juvenile Salmon (TSG-thermosalinigraph data)
공공데이터포털
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).
AFSC/ABL: Gulf of Alaska Diel Trawl Survey, 2005-2006
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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.
Ocean Salmon Distributions
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This project extends and advances existing ocean distribution and size models for Chinook Salmon, a major prey of Southern Resident Killer Whales (SRKW) and target of important fisheries, to provide ocean distribution estimates for multiple run-types (fall, summer, and spring Chinook) arising from rivers from California to Alaska by season and under variable oceanic conditions. It leverages very large tag-recapture databases that have been developed for Chinook Salmon over the past 50 years â hundreds of millions of fish tagged and millions recovered â and links these recoveries to a range of fisheries in which Chinook are targeted or captured as bycatch. It integrates data coast-wide, from Alaska to California, and over more than 30 years (1978-2015), to provide a first synthetic, quantitative description of Chinook distribution that can be used to understand the total Chinook prey field available to SRKW, fishers, and other predators in different seasons and under alternate ocean states. In addition, this projects examines long-term trends in Chinook salmon size and their biological implications. Chinook populations have shown pronounced trends toward smaller and younger fish returning to spawn, and these trends have accelerated in the last 15 years. This erosion of the age-size structure and life-history diversity may negatively affect population productivity via reductions in reproductive potential, and may compromise the long-term viability of populations and jeopardize the sustainability of Chinook salmon fisheries. Consequently, long-term shifts in life-history characteristics, which are likely caused by changing ecological conditions in the ocean, might need to be accounted for when estimating reference points for fishery management. This work supports ongoing efforts to recover SRKW populations, informs the SRKW critical habitat designation process and recovery plans, feeds into the PFMC SRKW ad hoc work group, and is directly in line with the NMFS Ecosystem-Based Fisheries Management Road Map and Policy as well as the National Climate Science Strategy.
AFSC/RACE/GAP/Conrath: Rockfish habitat and productivity (Coral)
공공데이터포털
The importance of high relief structure containing biotic habitat to rockfish and other species remains largely unknown. This data set was created to examine the importance of this habitat for Pacific ocean perch, northern rockfish, and dusky rockfish. These data were derived from four research cruises that occurred between May 2012 and December 2014. During the cruises, video data was recorded of habitat associations, plankton samples were collected, temperature profiles were recorded, and several types of biological samples were taken from trawl captured rockfish. These data will be recorded in several tables in an access database and video files will also be available.