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ICES WKIND REPORT 2013 ICES ADVISORY COMMITTEE

ICES CM 2013/ACOM:38

Report of the Workshop on DCF Indicators

21 - 25 October 2013

ICES Headquarters, Copenhagen, Denmark

International Council for the Exploration of the Sea Conseil International pour lExploration de la Mer

H. C. Andersens Boulevard 4446 DK-1553 Copenhagen V Denmark Telephone (+45) 33 38 67 00 Telefax (+45) 33 93 42 15 www.ices.dk info@ices.dk

Recommended format for purposes of citation:

ICES. 2013. Report of the Workshop on DCF Indicators, 21 - 25 October 2013, ICES Headquarters, Copenhagen, Denmark. ICES CM 2013/ACOM:38. 81 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.

2013 International Council for the Exploration of the Sea

ICES WKIND REPORT 2013 i

Contents

Executive Summary ............................................................................................................... 1

1 Introduction .................................................................................................................... 3

1.1 Terms of Reference ............................................................................................... 3 1.2 Introduction to DCF indicators ........................................................................... 3

1.3 WKIND approach to indicator review and update ......................................... 5

2 DCF Indicator 1: Conservation status of fish species (CSF) .................................. 6

2.1 Background to indicator ...................................................................................... 6 2.2 Data requirements ................................................................................................ 6

2.3 Review of CSF calculation protocol ................................................................... 7 2.3.1 Creating a vulnerable species list .......................................................... 7 2.3.2 Problems with calculation and interpretation of the

indicator .................................................................................................. 10 2.4 Recommendations .............................................................................................. 11

3 DCF Indicators 2 & 3 The Large Fish Indicator & the Mean Maximum length of Fishes ........................................................................................ 13

3.1 Introduction ......................................................................................................... 13 3.2 Procedures to calculate size-based (SBI) community indicators

(LFI, MML) .......................................................................................................... 13 3.3 The Baltic Sea ....................................................................................................... 17

3.4 The Bay of Biscay ................................................................................................ 20

3.5 The Celtic Sea ...................................................................................................... 23

3.6 North Sea ............................................................................................................. 26 3.7 Portuguese waters .............................................................................................. 32

3.8 Western Scottish Waters .................................................................................... 34

4 DCF Indicator 4 Size at maturation of exploited fish species ............................. 37

4.1 Background to indicator .................................................................................... 37 4.1.1 Theory...................................................................................................... 37 4.1.2 PMRN estimation ................................................................................... 38

4.2 PMRN suitability as a DCF indicator to measure effects of fishing on the ecosystem ................................................................................................. 38 4.2.1 Introduction ............................................................................................ 38 4.2.2 Procedure ................................................................................................ 39 4.2.3 Case studies ............................................................................................ 39

4.3 PMRN Conclusions and recommendations .................................................... 44 4.3.1 Conclusions............................................................................................. 44 4.3.2 Recommendations ................................................................................. 46

5 DCF Indicators 5 to 7: Spatial indicators on fishing pressures based on VMS data ....................................................................................................................... 47

ii ICES WKIND REPORT 2013

5.1 Background to indicators ................................................................................... 47 5.2 ICES Approach taken in to update indicators for WKIND2013 ................... 47

5.3 Review and update from WGSFD2013 ............................................................ 47 5.3.1 Excerpt from WGECO 2012 report ...................................................... 47 5.3.2 Conventions applied by WGSFD 2013 in light of WGECO

recommendations 2012.......................................................................... 50

5.4 Conclusions and outlook for DCF indicators 5-7 ........................................... 55

6 DCF Indicators 8 Discard rates of commercially exploited stocks .................. 57

6.1 Background to indicator .................................................................................... 57

6.2 Work and review by WKEID2010 and WGECO2012 .................................... 57

6.3 Discard data available to WKIND .................................................................... 58 6.4 Discard data: issues on consistency, data quality and raising

procedures ........................................................................................................... 59

6.5 Review and update of indicator ....................................................................... 61 6.5.1 Introduction ............................................................................................ 61 6.5.2 Procedure applied: ................................................................................. 61 6.5.3 Demonstration of indicator calculation using a case study ............. 63 6.5.4 Recommendations ................................................................................. 68

7 Conclusions and Recommendations ........................................................................ 69

8 References ..................................................................................................................... 71

Annex 1 - List of participants ............................................................................................. 76

Annex 2 WKIND ToR Workshop on DCF indicators ................................................. 77

ICES WKIND REPORT 2013 1

Executive Summary

The Workshop on update and calculation of the DCF indicators (WKIND), chaired by Leonie Dransfeld (Ireland) met in ICES HQ, Denmark 2125 October 2013 to ex-amine and report on the DCF indicators of fishing pressures/impacts, update their technical details and carry out the actual analysis for each indicator. The EU Data Collection Framework (EC 199/2008) supports the collection, management and analy-sis of data which underpins the scientific advice relating to the Common Fisheries Policy (CFP). In order to progress the implementation of the ecosystem-based ap-proach to fisheries management, nine pressure and state indicators are included in the DCF, which aim to measure the performance of the CFP in relation to the objec-tives of minimising the impact of fishing activities on the marine ecosystem.

The state indicators include three size based fish community indicators, namely the conservation status of fish, which monitors the change in biodiversity status of vul-nerable fish species (DCF1-CSF); the proportion of large fish which reflects the size structure of the community (DCF2-LFI) and the mean maximum length, which re-flects changes in life history composition (DCF3-MML). Analysis on the conservation status of fish revealed that the outcome of the indicator was highly sensitive to the decisions made by expert judgement. Issues were identified relating to reference pe-riods in relation to exploitation history, tracking depleted species, masking signals of single species trends, and overall reproducibility. It was recommended that single species metric indicators based on life history characteristics should be developed as an alternative to the CSF. Using regional expertise, indicators DCF-2 (LFI) and DCF-3 (MML) were updated based on proposed protocols for the different ICES ecoregions Baltic Sea, Bay of Biscay, Celtic Sea (separated into west of Scotland and Celtic Sea proper), Iberia and North Sea using regional and inhouse data from DATRAS.WKIND also assessed the temporal correlation between the LFI and MML vs. fishing (based on relative fishing

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