From “ladies in waiting” to age-0: understanding the spatial patterns of young Walleye pollock in Shelikof Strait, Alaska

Understanding the spatial patterns of spawning and survival for the young of commercially important fish species can best be achieved using a combination of in situ data and modeling efforts. Ideally, the population could be followed in time and space from the arrival in the early spring of adult fish ready to spawn to the hatching and growth of the larvae in May and on to the age-0 fish ready for their first winter. At the same time their marine environment would be directly sampled and characterized to enable scientists to relate larval survival to environmental conditions. However, constraints on direct observations and limits on available research ship time mean that models and spatial analyses must be used to bridge the gap between sampling on cruises.

This presentation will describe a project to characterize the spawning and survival of Walleye Pollock (Gadus chalcogrammus) in Shelikof Strait, Alaska in 2013 using data from three research cruises conducted that year. The cruises were 1) a hydroacoustics survey to locate adults preparing to spawn, 2) a plankton survey to locate and sample the resulting larvae, and 3) a summer/fall survey to locate and sample the age-0 fish. Geostatistical and particle tracking models will be used to link the cruises spatially to create a more complete description of the spatial patterns of this critical first year of life for these fish.