title: Quantifying the impact of environmental variables upon catch per unit effort of the blue shark Prionace glauca in the western English Channel.
abstract: The effect of environmental variables on blue shark Prionace glauca catch per unit effort (CPUE) in a recreational fishery in the western English Channel, between June and September 1998-2011, was quantified using generalized additive models (GAMs). Sea surface temperature (SST) explained 1·4% of GAM deviance, and highest CPUE occurred at 16·7° C, reflecting the optimal thermal preferences of this species. Surface chlorophyll a concentration (CHL) significantly affected CPUE and caused 27·5% of GAM deviance. Additionally, increasing CHL led to rising CPUE, probably due to higher productivity supporting greater prey biomass. The density of shelf-sea tidal mixing fronts explained 5% of GAM deviance, but was non-significant, with increasing front density negatively affecting CPUE. Time-lagged frontal density significantly affected CPUE, however, causing 12·6% of the deviance in a second GAM and displayed a positive correlation. This outcome suggested a delay between the evolution of frontal features and the subsequent accumulation of productivity and attraction of higher trophic level predators, such as P. glauca.
authors: National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, U.K.
authors: J D
authors: JD
authors: Mitchell
authors: K J
authors: KJ
authors: Collins
authors: P I
authors: PI
authors: Miller
authors: L A
authors: LA
authors: Suberg
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D005398:Fisheries; D008962:Models, Theoretical; D012623:Seawater / Q000737:chemistry; D012754:Sharks; D013696:Temperature; D006113:United Kingdom; D014872:Water Movements
chemical_list: D002734:Chlorophyll; D000077194:Chlorophyll A
keywords: environmental preferences; fisheries management; generalized additive model; recreational fishery