NPRB: Growth and Dispersal of Early Life History Stages of Arctic Cod and Saffron Cod Under Variable Climate Forcing

Scope of Work:

We propose to develop a biophysical transport model to simulate the dispersal of early life history stages of the two most abundant fish species, Arctic cod (Boregadus saida) and saffron cod (Eleginus gracilis), in the Chukchi Sea and the Beaufort Sea. These species form a crucial link from lower trophic levels to seabirds, marine mammals, and humans and have been recognized as potential target species for new fisheries in the Arctic. We combine observations of late larval and early juvenile stages of both species during the summer of 2012 and 2013 with laboratory-derived estimates of their temperature-dependent growth to parameterize an individual particle tracking model (TRACMASS) that includes growth and vertical movement. The model will be linked to a recently developed pan-arctic ocean circulation model(PAROMS) to test hypotheses about the origin and fate of young-of-the-year Arctic and saffron cod. Specifically, we aim to (1) identify likely spawning locations by tracking particles backward in time from known summer aggregations in the Chukchi Sea and (2) simulate pathways of dispersal from these aggregations to downstream nursery areas, which may include areas in the Beaufort Sea. Improved understanding of the growth, distribution, and movements of early life history stages of Arctic cod and saffron cod in the region, and of the connectivity between the Chukchi Sea and the Beaufort Sea, has several immediate and long-term benefits. It directly addresses research priorities identified in the Arctic Fisheries Management Plan, enhances required descriptions of Essential Fish Habitat for two key prey species, and provides benchmarks against which to assess future changes to the Arctic marine ecosystem that may result from new development in the Arctic and from anthropogenic climate change.

This project is jointly funded by the North Pacific Research Board and OSRI