Report of the Working Group on the Ecosystem Effects of Fishing Activities (WGECO)
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ICES WGECO REPORT 2012 ICES ADVISORY COMMITTEE ICES CM 2012/ACOM:26 Report of the Working Group on the Ecosystem Effects of Fishing Activities (WGECO) 11–18 April 2012 Copenhagen, Denmark International Council for the Exploration of the Sea Conseil International pour l’Exploration de la Mer H. C. Andersens Boulevard 44–46 DK-1553 Copenhagen V Denmark Telephone (+45) 33 38 67 00 Telefax (+45) 33 93 42 15 www.ices.dk [email protected] Recommended format for purposes of citation: ICES. 2012. Report of the Working Group on THE Ecosystem Effects of Fishing Activ- ities (WGECO), 11–18 April 2012, Copenhagen, Denmark. ICES CM 2012/ACOM:26. 192 pp. For permission to reproduce material from this publication, please apply to the Gen- eral Secretary. The document is a report of an Expert Group under the auspices of the International Council for the Exploration of the Sea and does not necessarily represent the views of the Council. © 2012 International Council for the Exploration of the Sea ICES WGECO REPORT 2012 | i Contents Executive Summary ............................................................................................................... 5 1 Opening of the meeting ................................................................................................ 7 2 Adoption of the agenda ................................................................................................ 8 3 ToRa) MSFD indicator and target evaluation ........................................................ 10 3.1 Criteria and a process for evaluating the scientific soundness and feasibility of national proposals for indicators and targets used to support the achievement of Good Environmental Status ............................. 10 3.1.1 Introduction ............................................................................................ 10 3.1.2 Criteria to evaluate metrics and indicators ........................................ 10 3.1.3 Process to evaluate metrics and indicators using criteria ................ 15 3.1.4 Criteria to evaluate targets ................................................................... 16 3.1.5 Targets evaluation process ................................................................... 19 3.1.6 Relationships between indicator and targets ..................................... 20 3.1.7 Final comments ...................................................................................... 20 3.1.8 References ............................................................................................... 21 3.2 Approaches for combining information provided by indicators and targets into an assessment of status .......................................................... 21 3.2.1 Regional sea scale assessments from subregional sea scale surveys .................................................................................................... 21 3.2.2 Multiple indicators for single assessments ......................................... 23 3.2.3 References ............................................................................................... 24 4 ToRb) DCF indicators ................................................................................................. 26 4.1 Introduction ......................................................................................................... 26 4.2 Conservation status of fish species ................................................................... 26 4.2.1 Method of calculation ............................................................................ 27 4.2.2 Calculation .............................................................................................. 27 4.2.3 Synthesis and recommendations ......................................................... 37 4.3 Proportion of large fish ...................................................................................... 41 4.3.1 Method of calculation ............................................................................ 41 4.3.2 Calculation .............................................................................................. 41 4.3.3 Synthesis and recommendations ......................................................... 42 4.4 Mean maximum length of fishes ...................................................................... 43 4.4.1 Method of calculation ............................................................................ 43 4.4.2 Calculation .............................................................................................. 43 4.4.3 Synthesis and recommendations ......................................................... 44 4.5 Size at maturation of exploited fish species .................................................... 44 4.5.1 Method of calculation ............................................................................ 44 4.5.2 Issues ....................................................................................................... 45 ii | ICES WGECO REPORT 2012 4.6 Fishing pressure based on VMS........................................................................ 46 4.6.1 Method of calculation ............................................................................ 46 4.6.2 Calculation: Dutch case study .............................................................. 47 4.6.3 Calculation: Italian case study ............................................................. 56 4.6.4 Synthesis and recommendations ......................................................... 61 4.7 Discarding rates of commercially exploited species ...................................... 62 4.8 Fuel efficiency of fish capture ........................................................................... 63 4.9 Link of DCF indicators to the MSFD ................................................................ 64 4.10 References ............................................................................................................ 65 5 ToRc) Ecosystem impact assessment of bottom fishing ....................................... 69 5.1 Introduction ......................................................................................................... 69 5.2 Approaches to ecological risk assessment ....................................................... 69 5.2.1 Ecological risk assessment of the effects of fishing (Hobday et al., 2007, 2011) ..................................................................................... 69 5.2.2 The MarLIN Approach ......................................................................... 74 5.2.3 US National Research Council approach ............................................ 77 5.2.4 Extended overlap models ..................................................................... 78 5.2.5 Population level models........................................................................ 79 5.2.6 Conclusions............................................................................................. 80 5.3 Background to NEAFC Request ....................................................................... 80 5.4 Response to NEAFC Request ............................................................................ 82 5.5 References ............................................................................................................ 89 6 ToRd) Indicators of Foodweb condition in reference to MSFD Descriptor 4 ................................................................................................................... 92 6.1 Introduction ......................................................................................................... 92 6.2 Gaps and shortcomings of current MSFD foodweb indicators .................... 93 6.3 Function, structure, and dynamics ................................................................... 95 6.4 Linking function, structure and dynamics through models ......................... 96 6.4.1 The heuristic value of models .............................................................. 96 6.4.2 Specific modelling examples ................................................................ 97 6.5 Fluxes as foodweb functions ........................................................................... 100 6.6 Determining abundances of functional groups from survey data ............. 103 6.7 Attributes of foodweb structure ..................................................................... 104 6.7.1 Rationale ............................................................................................... 105 6.7.2 Types of models ................................................................................... 105 6.7.3 Attributes of GES: size spectra ........................................................... 105 6.7.4 Attributes of GES: foodwebs at species resolution .......................... 106 6.7.5 Attributes of GES: functional groups ................................................ 108 6.7.6 Summary ............................................................................................... 109 6.8 Conclusions and recommendations ............................................................... 109 6.9 References .......................................................................................................... 109 7 ToRe) LFI development ............................................................................................ 118 ICES WGECO REPORT 2012 | iii 7.1 Comparison of LFI trends based on the North Sea beam trawl and otter trawl surveys ...........................................................................................