© British Crown Copyright 1998 Impacts of fishing on marine benthic habitats Michel J. Kaiser 1, Jeremy S. Collie 2, Stephen J. Hall 3, Simon Jennings 4, Ian R. Poiner 5 1 School of Ocean Sciences, University of Wales-Bangor, Menai Bridge, Anglesey, LL59 5EY, UK 2 Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island 02882, USA 3 Australian Institute for Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia 4 The Centre for Environment, Fisheries & Aquaculture Science, Lowestoft Laboratory, Lowestoft, NR33 0HT, UK 5 CSIRO Division of Marine Research, PO Box 120, Cleveland, Queensland 4163, Australia School of Ocean Sciences, University of Wales-Bangor

Demersal fishing gears Beam trawl rigged for clean ground © British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor Scale of disturbance and recovery rate Patch size 10 mm² 1 m²100 m² 10 8 m² 10 y 5y 1y 1 mo 1 day macrofauna eider rays walrusgrey whales anoxia Ice scour fishing Hydraulic dredging fishing Recovery time hurricanes tidal currents bait digging hurricanes

© British Crown Copyright 1998 The importance of Connell’s intermediate disturbance hypothesis School of Ocean Sciences, University of Wales-Bangor Less disturbance High Low Diversity Disturbances frequent Soon after a disturbance Disturbance large Disturbances frequent Soon after a disturbance Disturbance largeInfrequent Long after a disturbance Disturbance small Infrequent Long after a disturbance Disturbance small Grossly stressed community Climax community Increasing disturbance

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor WHAT CAN WE LEARN FROMEXPERIMENTS?

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor No. sppNo. indiv.Shannon’s H ___________________________________ Stable sediment unfished67±3***335±18**29±2*** fished31±3196±3215±1 Mobile sediment unfished29±5 ns 59±11 ns 21±4 ns fished27±598±2716±3 Infaunal responses to fishing disturbance

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor

Intertidal Dredging Scallop Dredging Intertidal Raking Beam Trawling Otter Trawling Eastern Australia Northern Europe East North America New Zealand South Australia LOCALITY GEAR Gravel Muddy Sand Biogenic Sand Mud Anthozoa Malacostraca Ophiuroidea Holothuroidea Maxillopoda Polychaeta Gastropoda Echinoidea Desmospongia Asteroidea Oligochaeta Bivalvia CLASS HABITAT RESPONSE RESPONSE META-ANALYSIS

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor mud/sandsand biogenic biogenic Relative response THE RECOVERY TRAJECTORY OF DIFFERENT HABITATS

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor Photograph: Jason Hall-Spencer

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor ENERGY SUBSIDIES Fishing can also alter habitat by inducing population changes in ‘habitat engineering species’ Log proportion seabed swept/yr starfish catch numbers

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor TESTING PREDICTIONS AT A REALISTIC SCALE

School of Ocean Sciences, University of Wales-Bangor Plymouth Sound Pots all year Trawling Jan - July Salcombe Towed gear all year Pots all year LOW EFFORT MEDIUM EFFORT HIGH EFFORT

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor Area 5, 4 and 3 Mean biomass of selected species Fishing effort Fishing effort LowMedHigh Hydroids Dead men’s fingers Dog cockle10120 Sea potato3273 Psammechinus8531

School of Ocean Sciences, University of Wales-Bangor Plymouth Sound Pots all year Trawling Jan - July Salcombe Towed gear all year Pots all year LOW EFFORT MEDIUM EFFORT HIGH EFFORT

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor Species rank Low fishing disturbance high fishing disturbance intermediate fishing disturbance biomass curve abundance curve Gear restriction management regimes help to conserve larger, emergent seabed fauna

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor CAN WE IMPLEMENT MANAGEMENT SYSTEMS THAT ARE USEFUL IN A CONSERVATION CONTEXT?

School of Ocean Sciences, University of Wales-Bangor 1998 Fishing Time hours/nm^2 blue <2 green 2-9 yellow 9-44 red >44

School of Ocean Sciences, University of Wales-Bangor 1999 Fishing Time hours/nm^2 blue <2 green 2-9 yellow 9-44 red >44

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor Effects of large-scale fishery closure off the eastern coast of the United States - secondary benefits for scallops

© British Crown Copyright 1998 School of Ocean Sciences, University of Wales-Bangor Conclusions Areas subject to fishing with towed bottom gear are dominated by lower biomass organisms and have less surface structure Areas exploited using pot gear have high biomass communities with greater surface relief It appears that with the application of common sense we can “have our cake and eat it” Areas closed to towed fishing gear can still be exploited while conserving the environment