MEPS 609:163-178 (2019)  -  DOI: https://doi.org/10.3354/meps12809

ABSTRACT: Alaska skate species utilize localized egg nursery sites along the interface of the continental slope and shelf in the eastern Bering Sea to lay eggs in high densities. These egg nursery sites persist across years and are thought to be related to environmental conditions. The objective of this analysis was to predict the potential habitat of skate egg nursery sites using species distribution models. Skate egg nursery locations (n = 26) for 6 species were identified from bottom trawl survey catches and underwater camera surveys. Maximum entropy models were developed using 10 environmental variables to predict the probability of suitable skate egg nursery habitat; 7 variables were included in the best model. Potential habitat peaked at seafloor slopes <2%, in areas of low temperature variability and in areas of high oxygen concentrations. These were the 3 most important variables in the model. Most of the predicted high probability egg nursery suitable habitat for skates was in canyons (e.g. Bering Canyon and the southern arm of Pribilof Canyon) in a relatively narrow band on the upper slope. The most important finding of this modeling study was that there is a limited area of the upper continental slope where conditions would support potential skate egg nursery areas; however, much of the area is unexplored and likely to remain so in the near future. Management actions for important conservation questions can look to modeling studies such as these for guidance in the absence of comprehensive surveys.

KEY WORDS: Nursery habitat · Maximum entropy · Suitable habitat · Elasmobranch · Alaska