Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8547
Title: Spatiotemporal variation in size-structured populations using fishery data: an application to shortfin mako (Isurus oxyrinchus) in the Pacific Ocean
Author: Mikihiko Kai, James T. Thorson, K. R. Piner, M. Maunder
Publication Year: 2017
Journal: Canadian Journal of Fisheries and Aquatic Sciences
Volume: 74
Issue: 11
Pages: 1765-1780
DOI: 10.1139/cjfas-2016-0327
Keywords: Spatio-temporal model, shortfin mako shark, Pacific ocean, habitat suitability, climate envelope model, spatial distribution, seasonal,
Abstract:

We develop a length-disaggregated, spatiotemporal, delta-generalized linear mixed model (GLMM) and apply the method to fishery-dependent catch rates of shortfin mako sharks (Isurus oxyrinchus) in the North Pacific. The spatiotemporal model may provide an improvement over conventional time-series and spatially stratified models by yielding more precise and biologically interpretable estimates of abundance. Including length data may provide additional information to better understand life history and habitat partitioning for marine species. Nominal catch rates were standardized using a GLMM framework with spatiotemporal and length composition data. The best-fitting model showed that most hotspots for ¿immature¿ shortfin mako occurred in the coastal waters of Japan, while hotspots for ¿subadult and adult¿ occurred in the offshore or coastal waters of Japan. We also found that size-specific catch rates provide an indication that there has been a recent increasing trend in stock abundance since 2008.

Full Text URL: http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2016-0327#.WfDAaP-nGUk
URL1: The next link will exit from NWFSC web site http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2016-0327#.WfDAaP-nGUk
URL2: The next link will exit from NWFSC web site https://doi.org/10.1139/cjfas-2016-0327
Theme: Recovery and rebuilding of marine and coastal species
Foci: Describe the relationships between human activities and species recovery, rebuilding and sustainability.
Describe the relationships between human activities and species recovery, rebuilding and sustainability.