This dataset contains 2-boat tow, push net and scoop net catches from the Yukon River Delta for 2014

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.

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.

The Alaska Fisheries Science Centers (AFSC) Status of Stocks and Multispecies Assessment (SSMA) Programs Fishery Interaction Team (FIT) conducted an offshore fish and invertebrate survey as part of the SHEFLZ Survey in the northeastern Chukchi Sea in 2013. The project is funded under the North Slope Borough s (NSB) State of Alaska Coastal Impact Assistance Program Project #6 Biological and Physical Oceanography of the Chukchi Sea Task I Offshore oceanographic and fish surveys.

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 dataset contains trawl and seine catches from Southeast Alaskan estuaries sampled from 1995 to 2008. The data also include physical variables (temp, salinity, turbidity), and shorezone shoreline classifications.

Upriver movements were determined for Chinook salmon Oncorhynchus tshawytscha returning to the Yukon River, a large, relatively pristine river basin. A total of 2,860 fish were radio tagged during 2002-2004, and 2,790 fish (98%) tracked upriver. Most fish exhibited continual upriver movements and strong fidelity to the terminal tributaries entered, with only a small percentage (2.5%) deviating from this pattern. Average movement rates were substantially slower for fish spawning in lower river tributaries (28-40 km d-1) compared to upper basin stocks (52-62 km d-1). Three distinct migratory patterns were observed, including a gradual decline, pronounced decline, and substantial increase in movement rate as the fish moved upriver. Stocks destined for the same region exhibited similar migratory patterns. Migratory patterns among individual fish within a stock showed substantial variation, but tended to reflect the regional pattern. Differences between consistently faster and slower fish explained 74% of the within-stock variation, whereas relative shifts in sequential movement rates between hares (faster fish becoming slower) and tortoises (slow but steady fish) explained 22% of the variation. Pulses of fish moving upriver were not cohesive. Fish tagged over a 4-day period took 14 and 16 d to pass tracking station sites 580 and 872 km upriver, respectively. Movement data provided valuable insights into the run dynamics of the return, but individual variation among fish complicates efforts to manage in-river fisheries. The diverse migratory patterns exhibited by the fish also suggest that movement studies based on small numbers of individuals may not adequately reflect the patterns exhibited by the larger population. Movement rates were substantially faster and the percentage of atypical movements considerably less than reported in more southern drainages, but may also reflect the pristine conditions within the Yukon River, wild origins of the fish, and relatively discrete run timing of the returns.

Summer surveys (Julyb??August) of juvenile salmon ecology along the continental shelf of the Gulf of Alaska are conducted annually by scientists from the Ocean Carrying Capacity program of the National Marine Fisheries Serviceb??s Auke Bay Laboratory. These surveys are an effort to link changes in salmon production to biological and physical factors in the ocean environment. An improved understanding of salmon distribution is one objective of this research. We identified the origin of juvenile chum salmon collected in transects from around the Gulf of Alaska in 2000 and 2001, using the presence of thermal marks in hatchery fish and the divergence of genetic characteristics among regional groups of populations.

NOAA Fisheries Alaska Regional Office and Alaska Fisheries Science Center’s Auke Bay Laboratories designed the Nearshore Fish Atlas of Alaska (NFA) to provide access to available data on the distribution, relative abundance, and habitat use of nearshore fishes in Alaska. The NFA is a spatially explicit, unified database of numerous nearshore catch datasets collected by various agencies and organizations in Alaska over the past several decades. The compiled datasets are from dozens of studies with different objectives and gear types (e.g., beach seines, purse seines, and trawls). The online NFA application has spatial and tabular tools for extensive searching, filtering, and downloading fully attributed data.