Nearshore Fish Assemblages of the Northeastern Chukchi Sea Alaska
October 17, 2012
The Arctic ecosystem is changing rapidly, yet information on nearshore fish assemblages for the northeastern Chukchi Sea is extremely limited. To address this information gap, we sampled nearshore fish assemblages with a beach seine and a small bottom trawl at six stations in the northeastern Chukchi Sea in August 2007, 2008, and 2009, and in September 2009. Catch and species composition differed by gear type and between sample periods, including the two in 2009. A total of 16039 fish representing 18 species were captured in 24 beach seine hauls, and 3108 fish representing 24 species were captured in 48 trawl tows. Beach seine catch was dominated by capelin (83%), and trawl catch was dominated by Arctic cod (56%). Species that were good discriminators between gear types were capelin (seine) and slender eelblenny (trawl), and unidentified small sculpins were the most common taxa caught with both gear types. Capelin and Arctic cod captured by either gear type were mostly juveniles (judging by size). Variability among sampling periods in catch and species composition within gear types can likely be attributed to annual variations in environmental conditions, including differences in water temperature (range: 2 ̊ – 9 ̊C). The shallow nearshore environment of the northeastern Chukchi Sea provides important habitat for many fish species and is extremely vulnerable to disturbance. Loss of sea ice from global warming may open up formerly inaccessible areas to oil and gas exploration, vessel traffic, and commercial fishing. Thus, long-term monitoring of nearshore fish assemblages in the Alaskan Arctic is necessary for managers to make informed decisions in this fragile environment.
The Arctic is an ecologically fragile area experiencing rapid changes in climate (warming) and loss of sea ice (Moline et al., 2008). In September 2012, sea ice covering the Arctic fell to its lowest extent since satellite records began in 1979 (National Snow and Ice Data Center, 2012). Loss of sea ice through climate change threatens marine life and habitat and has the potential to open formerly inaccessible areas to oil and gas exploration, increased vessel traffic, and development of fisheries. Nearshore fish habitat is also being affected because changes in sea ice have caused erosion of beaches adjacent to some Arctic communities (Lynch and Brunner, 2007). Ecosystem-wide changes already occurring in the Arctic include changes in the distribution and abundance of some fish (Genner et al., 2004; Rijnsdorp et al., 2009; Grebmeier et al., 2010). Because of the warming climate and the likelihood of increased human activity (particularly oil and gas exploration) in the northeastern Chukchi Sea of Alaska, more information is needed on nearshore fish assemblages for resource managers to make informed decisions.