Response of Catch-per-Unit-Effort to Spatial and Environmental Factors: An Exploratory Data Analysis Using Generalized Additive Models

Date of Award

3-11-2007

Document Type

Undergraduate Capstone Project

Degree Name

Master of Env Policy Mgmt

Organizational Unit

University College, Environmental Policy and Management

Disciplines

Environmental Policy & Mgmt

First Advisor

John Hill

Keywords

Additive, Catch-per-unit-effort, Depth, Distribution, Fish, Fisheries, Catch effort, Environmental aspects, Generalized, Model, Spatial, Spatial ecology, Temperature

Abstract

Understanding spatial distributions and how environmental conditions influence catch-per-unit-effort (CPUE) is important for increased fishing efficiency and sustainable fisheries management. This study investigated the relationship between CPUE, spatial factors, temperature, and depth using generalized additive models. Combinations of factors, and not one single factor, were frequently included in the best model. Parameters which best described CPUE varied by geographic region. The amount of variance, or deviance, explained by the best models ranged from a low of 29% (halibut, Charlotte region) to a high of 94% (sablefish, Charlotte region). Depth, latitude, and longitude influenced most species in several regions. On the broad geographic scale, depth was associated with CPUE for every species, except dogfish. Latitude and longitude influenced most species, except halibut (Areas 4 A/D), sablefish, and cod. Temperature was important for describing distributions of halibut in Alaska, arrowtooth flounder in British Columbia, dogfish, Alaska skate, and Aleutian skate. The species-habitat relationships revealed in this study can be used to create improved fishing and management strategies.

Publication Statement

Copyright is held by the author. Permanently suppressed.

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