Modeling of the spatial distribution of Pacific spiny dogfish ( Squalus suckleyi) in the Gulf of Alaska using generalized additive and generalized linear models

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Gasper, Jason R., Kruse, Gordon H.
• Other Authors: Hilborn, Ray
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2013
• Subjects: Kodiak; Alaska; spiny dogfish
• Online Access: http://dx.doi.org/10.1139/cjfas-2012-0535; http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2012-0535; http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2012-0535

The Pacific spiny dogfish (Squalus suckleyi) is a common bycatch species in the Gulf of Alaska. Their spatial distribution is poorly understood, as most catch is discarded at sea. We analyzed spiny dogfish spatial distribution from fishery-dependent and -independent observations of longline gear between 1996 and 2008 using generalized additive and generalized linear models. Poisson, negative binomial, and quasi-Poisson error structures were investigated; the quasi-Poisson generalized additive model fit best. Models showed that spiny dogfish catches were concentrated east of Kodiak Island in waters ≤100 m deep. Results facilitate design of future spiny dogfish assessment surveys and identification of areas in which to focus at-sea observations for fishing mortality estimation, and provide the basis for first-ever designation of spiny dogfish essential fish habitat, despite US legal requirements for essential fish habitat designations since 1996. Identified areas of high bycatch may expedite spatial management by indicating areas in which directed spiny dogfish fisheries could be focused or, conversely, areas in which heightened conservation and catch accounting efforts would be most effective to prevent overfishing of this long-lived, late-maturing species.