Determining Recommended Levels of Harvest on Pacific Halibut
by
Brittany J. Parker
Mercyhurst College
Coauthors: Tamar E. Wilson (Mount Holyoke College) Michael A. Rutter (Penn State Erie, The Behrend College)

Using data for catch and effort of Pacific halibut (Hippoglossus stenolepis) provided by the International Pacific Halibut Commission, we created a logistic growth based surplus production model representative of six regions off the coast of Alaska. We explored the effect of changes in fishing gear, density-dependent catchability, migration patterns, and changing carrying capacity on a model of fish biomass. Parameters estimates were determined using maximum likelihood techniques and Akaike’s Information Criteria was used to compare models. After choosing the model that best fit the observed data, recommendations on harvest levels can be suggested by examining the maximum sustainable yield predicted by the model. In order to account for uncertainty in the parameter estimates, bootstrapping techniques were used to determine harvest levels that maximize amount of halibut harvest without overfishing the population.

Date received: July 31, 2006