Arctic Relict Fauna and Flora

Through the Coastal Marine Institute (CMI), a partnership between the University of Alaska Fairbanks and the Minerals Management Service (now BOEM), Cook Inlet RCAC partnered on the project “Evaluating a Potential Relict Arctic Invertebrate and Algal Community on the West Side of Cook Inlet.” This project was an analysis of archived samples and specimens collected during intertidal and subtidal surveys in Cook Inlet to evaluate whether they are relict Arctic species. The study is based on previous work conducted on the lower west side of Cook Inlet when taxonomic identifications of epifaunal invertebrates collected in the 1970s for the Outer Continental Shelf Environmental Assessment Program bore a striking resemblance to species reported for the Alaskan Arctic. Additional information provided by other historical invertebrate collections in the area indicate that these west side species and assemblages more closely matched Arctic species and assemblages than those on Cook Inlet’s east side or in other areas of the Gulf of Alaska and this study will further evaluate these historical specimens. Appropriate international taxonomic experts for each group of species were contracted to provide the level of detail required to assess the potential for a relict Arctic flora and fauna assemblage on Cook Inlet’s west side.

Given the potential isolation of an Arctic relict assemblage, these western Cook Inlet populations could be at risk from habitat perturbation and might be sensitive indicators of climate change or other ecological shifts. In addition, industrial development could threaten these populations and baseline information is needed to fully evaluate that potential. Monitoring their distributions and abundance could provide insight into changes in marine fauna and flora that may occur with changing physical oceanographic conditions. The persistence of these species in spite of their restricted distributions, relative to the prevailing currents, raises some interesting questions about their reproductive mechanisms and strategies. This evaluation addressed the CMI framework need for “better understanding marine, coastal or human environments affected or potentially affected by offshore oil and gas or other mineral exploration and extraction on the outer continental shelf.”

This study evaluated archived specimens of intertidal and subtidal invertebrates and algae from Cook Inlet’s west side to compare assemblages to other areas of Cook Inlet and Alaska. There has been speculation in the literature that these assemblages on the west side of Cook Inlet more closely reflect species that occur in the Alaskan Arctic than those in other areas of Cook Inlet. The study compared species lists from Cook Inlet’s west side to species lists form the Arctic and other areas of Cook Inlet (e.g. Kachemak Bay). In addition, archived samples from the University of Alaska museum were sorted and identified to the lowest taxon possible by taxonomists who specialize in the various classes of plants and animals. We found a strong relationship between Arctic and west-side bryozoan fauna and weaker relationships for other invertebrate groups. Our results suggest that the disjunct distributions of many Arctic-affiliated species, both algae and invertebrates may be due to a contraction in their distributional ranges in the north Pacific from wider distributions occupied before the most recent glacial retreat.

The final report can be found here.