Habitat Mapping and Production Estimates of Skate Nursery Sites in the Eastern Bering Sea, NPRB Project 808

Four Alaska skate nursery sites in the eastern Bering Sea were investigated
using an autonomous underwater vehicle. Data collected at each site included
thousand of high resolution digital images, bottom depth, and bottom temperature.
Analysis of images suggests egg cases were highly aggregated over extremely small
areas on flat sandy to muddy bottom. Bottom temperatures ranged between 3.23-4.14
degree C at all sites and varied little ate any one site. Nursery sites occurred at
greater depths and cooler waters with increased latitude. A comparison of direct egg
case counts at nursery sites with recruit estimates from bottom trawl surveys and
production models suggested a mismatch between the two by several orders of
magnitude. Explanations include uncertainty in the recruitment models and trawl
estimates or the existence of many more nursery sites in the eastern Bering Sea for
the Alaska skate. Embryo development time was documented in the laboratory through
controlled experimental temperatures at 4.2 degree C and 5.4 degree C The results
showed that water temperature is a key determining factor in embryo development
time. At the warmest experimental temperature (5.4 degree C) it is projected embryo
development will take 2.9 years and at the cooler (4.2 degree C) it is estimated to
take 3.7 years. These datasets were archived as part of the North Pacific Research Board legacy project recovery effort undertaken by Axiom Data Science and NPRB in 2025. The goal of the recovery effort was to assess the NPRB-funded data projects from 2002 to 2014 and archive final data packages that were ready for publication to increase long-term accessibility and discoverability. Data packages were archived as is given limited funding and resources.