Critical trophic links in southern Chukchi Sea lagoons

Abstract

Arctic lagoons support a variety of fish, bird and marine mammal species, as well as subsistence fisheries that are critical to local food security along the Chukchi and Beaufort sea coasts. In summer 2015, diet samples from seven lagoon fishes were non-lethally collected in three lagoons along the Northwest Alaska coastline. Using these samples, we determined that the key prey species that supported these particular lagoon food webs were mysids, chironomids and Ninespine Stickleback. We identified the relative importance of freshwater/terrestrial and marine prey sources in lagoon fish diets and identified three key functional feeding groups of fishes: microbenthivore/zooplanktivores, macrobenthivore/piscivores, and piscivores. Several key predators were found in the microbenthivore/zooplanktivore group indicating a high degree of redundancy, which was lacking in the other functional feeding groups. This suggests that this group has the greatest resiliency, whereas other groups may be more vulnerable to changes in lagoon habitats. Functional groups with less redundancy, such as the upper trophic levels, may be good indicator species for identifying potential impacts to Arctic lagoons from climate change.