Date of Award

Fall 12-16-2016

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Yong Chen

Second Committee Member

James Wilson

Third Committee Member

Teresa Johnson

Additional Committee Members

David Hiebeler

Abstract

The complex metapopulation structure of groundfish stocks in the Gulf of Maine, particularly Atlantic cod (Gadus morhua), is largely ignored under the current system of broad-scale stock assessment and management. This mismatch of biological and administrative scales has contributed to severe overall stock decline and localized serial depletion of Gulf of Maine cod. Such chronic management failure has led to growing calls for a more area-based, finer-scale approach to managing groundfish in the Gulf of Maine. A primary difficulty hindering the development of finer-scale groundfish management has been the challenge of estimating fishing mortality upon local stock components. However, generic system dynamics models may permit early identification of stock components being pushed toward instability by excessive fishing pressure. Interpolation of existing fishery-independent survey data within approximate subpopulation boundaries permits the construction of estimated abundance indices for metapopulation components. This study utilizes a model-based approach to classify these indices into risk categories based on the likelihood that they may be trending toward more unstable dynamics. Such an approach offers a potential solution to the problems of limited data and logistical impracticality that prevent the use of analytical assessment models at finer spatial scales.

Comments

Master of Science in Marine Biology and Master of Science in Marine Policy

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