Space‐time investigation of the effects of fishing on fish populations

Species distribution models ( SDM s) are important statistical tools for obtaining ecological insight into species–habitat relationships and providing advice for natural resource management. Many SDM s have been developed over the past decades, with a focus on space‐ and more recently, time‐dependence. However, most of these studies have been on terrestrial species and applications to marine species have been limited. In this study, we used three large spatio‐temporal data sources (habitat maps, survey‐based fish density estimates, and fishery catch data) and a novel space‐time model to study how the distribution of fishing may affect the seasonal dynamics of a commercially important fish species (Pacific Dover sole, Microstomus pacificus ) off the west coast of the USA . Dover sole showed a large scale change in seasonal and annual distribution of biomass, and its distribution shifted from mid‐depth zones to inshore or deeper waters during late summer/early fall. In many cases, the scale of fishery removal was small compared to these broader changes in biomass, suggesting that seasonal dynamics were primarily driven by movement and not by fishing. The increasing availability of appropriate data and space‐time modeling software should facilitate extending this work to many other species, particularly those in marine ecosystems, and help tease apart the role of growth, natural mortality, recruitment, movement, and fishing on spatial patterns of species distribution in marine systems.