AFSC/ABL: Stock composition, timing, and spawning distribution of Yukon River Chinook salmon
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Radio telemetry was used to determine the distribution, locate spawning sites, and evaluate the tagging response of wild Chinook salmon Oncorhynchus tshawytscha returning to a large, free-flowing river basin. A total of 2,860 fish were radio tagged in the lower Yukon River and tracked upriver. Fish traveled to spawning areas throughout the basin, ranging from several hundred to over 3,000 km from the tagging site. We found similar distribution patterns across years, suggesting that the major components of the return were identified. Most spawning fish were clustered in a number of principal tributaries, although small numbers of fish were located in other spatially-isolated areas. The cumulative contribution of these minor stocks was appreciable, making up 28-31% of the tagged sample. There was suggestive evidence of mainstem spawning in upper reaches of the basin. Large-scale elevation and physiographic data were useful in categorizing spawning areas, with most fish returning to relatively entrenched upland rivers. Fish were largely absent in lowland reaches characterized by meandering, low gradient, alluvial channels often associated with main river floodplains. The fish generally responded well to the capture, handling, and tagging procedures with most (2,790, 97.6%) resuming upriver movements, although the fish initially displayed a negative tagging response, with slower migration rates observed immediately after release. The duration of this response was relatively short (several days) and less severe as the fish moved upriver. The swimming speeds of radio-tagged fish after the initial delay were comparable to estimates for untagged fish, further suggesting that the capture, handling, and tagging methods used were relatively benign. Identifying the primary components of the run (including both major and minor stocks) and determining site-specific utilization patterns can fundamentally enhance salmon management in large river basins, and facilitate research and conservation efforts.
AFSC/FMA/NPRB Alternative Catch Monitoring Table and Column Definitions
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These data arise from a field study of groundfish catch monitoring in Kodiak, AK trawl fisheries. Two monitoring components were included in the study: 1) at-sea sampling methods used by observers to sample species composition of catch and 2) shore-side sampling of delivered catch by observers to validate landings species composition reports. The at-sea portion of the study consisted of a side-by-side comparison (two observers) of a proposed new sampling method and the standard sampling method. Observer data were recorded at-sea on paper and transferred to an Oracle database. The shoreside component of this study consisted of observer species composition sampling in plants for later comparison with landings data. The shore-side data were collected by observers in processing plants, recorded on paper and transferred to an Oracle database. Data collection started in April 2011 and continued through August 2011. Third party landings data (NOAA Fisheries, Alaska Regional Office, Sustainable Fisheries Division) that were used in the analysis are stored in an oracle database. Data for both project components (at-sea and shoreside) were collected during normal fishing activities onboard commercial trawl catcher vessels and during normal processing activities in shore-based processing plants.
AFSC/NMML: Cook Inlet Beluga Opportunistic Sightings, 1975 to 2015
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As a part of National Marine Fisheries Service (NMFS) management of the endangered Cook Inlet beluga whale population, a database of opportunistic beluga whale sightings was compiled from reports made by the general public, aircraft patrols, wildlife surveys, and military and industry monitoring studies. Sightings are reported to NMFS Alaska Regional (AKR) office personnel either by voice- or e-mail. Sighting data are then transcribed and sent to the NMFS National Marine Mammal Laboratory (NMML) for entry into the database. Data are first assessed for quality during transcription by NMFS AKR personnel. Secondary review and confirmation is undertaken by NMFS NMML personnel prior to entry of data into the Access Database.
AFSC/ABL: National Marine Fisheries Service - Alaska Sablefish Tag Database
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This data set captures the tag release and recovery information for sablefish from the early 1970s until present. It also contains tag release and recovery data for several other species (shortspine thornyheads, Greeland turbot, Pacific sleeper sharks, spiny dogfish, and lingcod) which have been tagged by NMFS in AK since the late 1990s.
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.