A multispecies age-structured assessment model for the Gulf of Alaska
Date of Original Version
Predation is the largest source of mortality for marine fish and may be an important process in regulating population size. Recent population models have attempted to quantify predation separately from other sources of natural mortality. Building upon such work, a multispecies age-structured assessment model (MSASA) for the Gulf of Alaska was developed, which included arrowtooth flounder (Atheresthes stomias), Pacific cod (Gadus macrocephalus), and walleye pollock (Theragra chalcogramma). Predation mortality was a flexible function of predator and prey abundances that was fitted to stomach-content data. A proof of concept illustration is presented here, assessing model outputs against a set of single-species models. The MSASA model was able to successfully estimate predation between species and integrate it into total mortality. Significant predation occurred on younger pollock and flounder. Results indicate a significant change in predation over time on pollock as a function of increased arrowtooth flounder abundance. Estimating mortality and other parameters for three species simultaneously is complex, and the advantage of greater biological realism of MSASA comes at the expense of greater uncertainty in parameter estimation.
Publication Title, e.g., Journal
Canadian Journal of Fisheries and Aquatic Sciences
van Kirk, Kray F., Terrance J. Quinn, and Jeremy S. Collie. "A multispecies age-structured assessment model for the Gulf of Alaska." Canadian Journal of Fisheries and Aquatic Sciences 67, 7 (2010). doi: 10.1139/F10-053.