Atlas Of Nearshore Fish Of Alaska: A Synthesis Of Marine Surveys From 1998 To 2011
October 17, 2012
Information on the distribution, abundance, species composition, habitat use, and life-stage of 121 fish species caught in nearshore marine waters of Alaska is synthesized in this atlas. Data were collected by scientists from the Alaska Fisheries Science Center, Auke Bay Laboratories over a 14-year period (1998-2011). Fish were captured with a beach seine mostly in summer in four different habitat types (bedrock outcrops, eelgrass meadows, understory kelp beds, and sand or gravel beaches) at 93 locations and 555 unique sites within nine regions of Alaska spanning from the Arctic to southeastern Alaska. Data on species assemblages are summarized among regions and habitat types. Distribution maps, graphs of abundance and length frequency, and photos are presented for each species. This atlas is unique because the same methods were used to sample fish and habitat over a large extent of coastal Alaska, and the core group of researchers doing the work remained the same throughout all years.
This synthesis reveals a wealth of information about nearshore fish of Alaska. Our major findings include:
1. Nearshore marine waters support an abundant and diverse array of fish; we captured an estimated 718,345 fish representing at least 121 species from 29 families.
2. Four commercially important species (walleye pollock, Theragra chalcogramma; Pacific herring, Clupea pallasii; pink salmon, Oncorhynchus gorbuscha; and chum salmon, O. keta) accounted for 55% of our total overall catch.
3. Species distribution patterns varied greatly among regions; only two species (pink salmon and threespine stickleback, Gasterosteus aculeatus) were caught in all nine regions.
4. Abundance and species richness varied by region; mean catch-per-unit-effort (CPUE) ranged from 124 fish in Southcentral Alaska to 1,202 fish in the Aleutian Islands, and species richness ranged from 17 species in Bristol Bay to 67 species in Southeast Northern Inside.
5. Species assemblages differed among habitat types in most regions, and mean CPUE and species richness were usually greatest in eelgrass or kelp.
6. Species composition by habitat type was unique in some regions (e.g., sand, Bristol Bay), largely the result of the presence of a few species (e.g., rainbow smelt, Osmerus mordax) that were absent in other regions.
7. Most fish captured were juveniles, highlighting the importance of the nearshore to critical early life-history stages of managed and ecologically important species.
8. Forage species (e.g., Pacific herring and Pacific sand lance, Ammodytes hexapterus) may be the most susceptible fish to shoreline disturbance because of their use of nearshore habitats for feeding and shelter as juveniles and for spawning as adults.
9. The high abundance and diversity of fish in eelgrass and kelp warrant special protection of these habitats in the event of an oil spill or other shoreline disturbance, especially if these habitats are known spawning areas (e.g., Pacific herring).
10. Our nearshore dataset is extremely important to managers responsible for oil spill response, natural resource damage assessment, essential fish habitat identification, and long-term monitoring.