Marine Fish Conservation Global evidence for the effects of selected interventions Natasha Taylor, Leo J. Clarke, Khatija Alliji, Chris Barrett, Rosslyn McIntyre, Rebecca0 K. Smith & William J. Sutherland CONSERVATION EVIDENCE SERIES SYNOPSES Marine Fish Conservation Global evidence for the effects of selected interventions Natasha Taylor, Leo J. Clarke, Khatija Alliji, Chris Barrett, Rosslyn McIntyre, Rebecca K. Smith and William J. Sutherland Conservation Evidence Series Synopses 1 Copyright © 2021 William J. Sutherland This work is licensed under a Creative Commons Attribution 4.0 International license (CC BY 4.0). This license allows you to share, copy, distribute and transmit the work; to adapt the work and to make commercial use of the work providing attribution is made to the authors (but not in any way that suggests that they endorse you or your use of the work). Attribution should include the following information: Taylor, N., Clarke, L.J., Alliji, K., Barrett, C., McIntyre, R., Smith, R.K., and Sutherland, W.J. (2021) Marine Fish Conservation: Global Evidence for the Effects of Selected Interventions. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK. Further details about CC BY licenses are available at https://creativecommons.org/licenses/by/4.0/ Cover image: Circling fish in the waters of the Halmahera Sea (Pacific Ocean) off the Raja Ampat Islands, Indonesia, by Leslie Burkhalter. Digital material and resources associated with this synopsis are available at https://www.conservationevidence.com/ 2 Contents Advisory Board ................................................................................................................... 8 About the authors .............................................................................................................. 9 Acknowledgements .......................................................................................................... 10 1. About this book ....................................................................... 11 1.1 The Conservation Evidence project ............................................................................ 11 1.2 The purpose of Conservation Evidence synopses ....................................................... 12 1.3 Who is this synopsis for? ............................................................................................ 12 1.4 Background ................................................................................................................. 13 1.5 Scope of the review .................................................................................................... 14 1.6 Methods ...................................................................................................................... 15 1.7 How you can help to change conservation practice ................................................... 29 1.8 References .................................................................................................................. 29 2. Threat: Biological resource use ................................................. 30 Spatial and Temporal Management ............................................................................... 30 2.1 Establish long-term fishery closures ........................................................................... 30 2.2 Establish temporary fishery closures.......................................................................... 33 2.3 Cease or prohibit all commercial fishing .................................................................... 37 2.4 Cease or prohibit all (mobile and static) fishing gears that catch bottom (demersal) species .............................................................................................................................. 42 2.5 Cease or prohibit mobile fishing gears that catch bottom (demersal) species and are towed across the seafloor ................................................................................................ 44 2.6 Cease or prohibit shellfish dredging ........................................................................... 50 2.7 Cease or prohibit mobile midwater (pelagic) fishing gears ....................................... 51 2.8 Cease or prohibit all non-towed (static) fishing gears ............................................... 53 2.9 Cease or prohibit line fishing ...................................................................................... 53 2.10 Cease or prohibit spearfishing .................................................................................. 54 2.11 Cease or prohibit customary fishing (indigenous fishing for cultural and community needs) ............................................................................................................................... 58 2.12 Allow only small-scale, traditional (artisanal) fishing ............................................... 59 2.13 Allow periodic fishing only ....................................................................................... 60 2.14 Establish territorial fishing use rights ....................................................................... 61 2.15 Cease or prohibit all types of fishing in a marine protected area ............................ 62 2.16 Cease or prohibit all fishing activity in a marine protected area with limited exceptions ........................................................................................................................ 98 2.17 Control human activity in a marine protected area with a zonation system of restrictions ...................................................................................................................... 101 2.18 Restrict fishing activity (types unspecified) in a marine protected area ............... 106 3 Reduce Unwanted Catch and Discards, and Improve Survival of Returned or Escaped Fish .............................................................................................................................. 108 Deployment of fishing gear and mode of operation ...................................................... 108 2.19 Deploy fishing gear at selected depths to avoid unwanted species ...................... 108 2.20 Deploy fishing gear at selected times (day/night) to avoid unwanted species ..... 111 2.21 Selectively avoid the capture of unwanted fish based on temperature distribution ..................................................................................................................... 112 2.22 Reduce duration of fishing gear deployments ....................................................... 113 2.23 Change the towing speed of a trawl net ................................................................ 116 2.24 Reduce the hauling speed of a trawl net ................................................................ 117 Handling of catch ........................................................................................................... 117 2.25 Use a different method to sort or bring catch onboard......................................... 117 2.26 Reduce the duration of exposure to air of captured fish before release .............. 118 2.27 Release protected or species of concern alive after capture ................................. 120 2.28 Establish handling and release protocols in non-recreational fisheries ................ 123 Quotas ............................................................................................................................ 125 2.29 Set quotas for non-targeted commercial catch ..................................................... 125 2.30 Legislate to oblige fishers to retain and land all catch of species managed by quotas ........................................................................................................................................ 126 Fishing gear modification ............................................................................................... 127 2.31 Use artificial light on fishing gear ........................................................................... 127 2.32 Attach an electropositive deterrent to fishing gear ............................................... 129 2.33 Use a larger mesh size ............................................................................................ 133 2.34 Use a different hook type ....................................................................................... 149 2.35 Use a different bait type ......................................................................................... 160 2.36 Modify longline configuration ................................................................................ 165 2.37 Modify gillnet or entangling (trammel/tangle) net configuration ......................... 167 2.38 Modify fishing trap/pot configuration ................................................................... 170 2.39 Fit escape devices (panels/grids) to encircling nets ............................................... 180 2.40 Modify the design or configuration of trawl gear (mixed measures) .................... 182 2.41 Change the size of the main body of a trawl net ................................................... 191 2.42 Decrease the circumference or diameter of the codend of a trawl net ................ 192 2.43 Modify the design or configuration of trawl doors ................................................ 199 2.44 Modify a bottom trawl to raise parts of the gear off the seabed during fishing ... 201 2.45 Modify design