Burton Island – 1950s Historical Chukchi and Beaufort Sea zooplankton communities, Hopcroft R.

A major challenge in climate-related studies is lack of historical data against which to assess biological
response to changes in the physical environment. Here we report on the zooplankton collected in the Beaufort Sea,
Chukchi Sea and adjoining Canada Basin during 1950-1953 cruises by the US Coast Guard’s Burton Island and during
1949 in the Chukchi by the Cedarwood using a 363/156 µm mesh Nansen net and ~150 µm mesh net, respectively. Although
the Burton Island samples total 135, inadequate preservation rendered only 65 of these samples suitable for re-analysis;
similarly only 24 of the 35 Cedarwood samples were suitable for analysis. For the Burton Island, we determined an average
abundance of 452 individuals m-3 and 6.58 mg DW m- and 69 individuals m-3 and 0.8 mg DW m-3 were captured for the holozooplankters
and the merozooplankters respectively. For the Cedarwood, we dermined that an average abundance of 806 individuals m-3 and 20.5 mg
DW m-3 were captured for the holozooplankters, plus 262 individuals m-3 and 3.6 mg DW m-3 for merozooplankters. The most prominent
holoplanktonic taxa were copepods and their composition varied between the Chukchi and Beaufort domains, as confirmed by
multivariate analysis. Some caution must be exercised in using these data as specific taxa and/or life stages may have been
removed from the collections over time and not recorded. Nonetheless, this data establishes that Pacific-affinity zooplankton
species have been advected into the Chukchi and across the shelf break for at least the past 60 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.