Evaluation of a US west coast groundfish habitat conservation regulation via analysis of spatial and temporal patterns of trawl fishing effort

Abstract

We examined the extent to which the 2000 Pacific Fishery Management Council footrope restriction shifted and reduced trawl fishing effort on Oregon fishing grounds, related these changes to the seafloor habitat type over which they occurred, and developed methods for enhancing spatial review of fishing effort. Density analysis of trawl start locations demonstrated how fishing efforts increased and decreased in relation to habitat distribution and fishery management actions between 1995 and 2002. Trawl effort patterns exhibited significant interannual variability and were patchy in distribution. Tow end-point locations from 1998 to 2001 were retrieved from manual logbooks for five reference sites located in proximity to rocky habitat. Trawl towlines were mapped and demonstrated a marked enhancement of fine-scale fishing effort resolution. Spatial shifts in fishing intensity (measured as kilometres towed) away from rock habitat were evident at all reference sites after the footrope restriction, with an average reduction of 86%. Some slight shifts into surrounding unconsolidated sediments also occurred. Our results indicate that the footrope restriction, in conjunction with associated landing limits, was effective in protecting rocky habitats from trawl fishing impacts. Continued spatial monitoring of trawl data would assist in fishery management assessment of conservation objectives for depleted groundfish and essential fish habitat protection.