title: Cascading ecological effects of eliminating fishery discards.
abstract: Discarding by fisheries is perceived as contrary to responsible harvesting. Legislation seeking to end the practice is being introduced in many jurisdictions. However, discarded fish are food for a range of scavenging species; so, ending discarding may have ecological consequences. Here we investigate the sensitivity of ecological effects to discarding policies using an ecosystem model of the North Sea--a region where 30-40% of trawled fish catch is currently discarded. We show that landing the entire catch while fishing as usual has conservation penalties for seabirds, marine mammals and seabed fauna, and no benefit to fish stocks. However, combining landing obligations with changes in fishing practices to limit the capture of unwanted fish results in trophic cascades that can benefit birds, mammals and most fish stocks. Our results highlight the importance of considering the broader ecosystem consequences of fishery management policy, since species interactions may dissipate or negate intended benefits.
authors.affiliation: Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Heath
authors.affiliation: Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK.
authors.forename: Robin M
authors.initials: RM
authors.lastname: Cook
authors.affiliation: Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK.
authors.forename: Angus I
authors.initials: AI
authors.lastname: Cameron
authors.affiliation: Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Morris
authors.affiliation: Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Speirs
mesh_terms: D000818:Animals; D001717:Birds; D002591:Cetacea; D003198:Computer Simulation; D017753:Ecosystem; D005398:Fisheries; D005399:Fishes; D020387:Food Chain; D009659:North Sea