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1 Indicators for fisheries management: a French experience Marie-Joëlle Rochet, Verena Trenkel, Jean- Charles Poulard, and Jacques Bertrand Robert Bellail, Olivier Le Pape, Jean-Claude Mahé, Jocelyne Morin, Ivan Schlaich, Arnauld Souplet From: ICES Journal of Marine Science, in press SCMEE Transversal workshop on ecosystem approach to fisheries Salammbo, 7-9 September 2005
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2 Outline Definitions and context A method to combine indicators for a diagnosis of fishing impacts A French experience: using survey data to estimate indicators and to inform stakeholders
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3 What is an indicator? Something that can be measured and monitored on an appropriate time-scale Something related to a management objective: “Something we care about” Something simple and understandable
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4 Ecosystem approach to fisheries management Focus on marine ecosystems rather than single stocks –bycatch species –habitats –food webs... Consider several levels of organisation Consider multiple uses and objectives Impact of fishing on ecosystems vs consequences of ecosystem state for fisheries
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5 Why do we need indicators for fisheries management? Monitor Status Support Decision-Making Inform Dialogue Evaluate Performance of Management Actions Provide Understanding Need Reference Points/States/Something!
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6 Indicators, reference points and decision criteria Hall & Mainprize, 2004
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7 Reference direction Increasing fishing impact Target RP Limit RP Indicator I 1 Factor A Factor B Factor C Use expected effect of fishing as a “reference direction” for each indicator
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8 Reference directions: Several indicators Increasing fishing impact Indicator 2 Indicator 1 Indicator 3 Combine changes in indicators relative to expected effect of fishing
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9 Where you want to go depends on where you start from Retrospective initial state assessment determines undesirable directions –light fishing impact do not increase fishing impact –severe fishing impact do not stay here do not increase fishing impact Combine indicator trends to assess if system moved towards these directions
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10 Combine trends to improve interpretation More small and large fish: good recruitment and low mortality (F or M) Shift in spatial distribution: more fish in survey area More old fish: mortality decreases (F or M) and slower growth More small fish and faster growth Fishing Environment Fish. x Envir. Abundance Average length
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11 Decide which combinations you like Not impacted initial state do not increase fishing impact p=0.9025 p=0.04875 p=0.025p=0.95p=0.025 p=0.95 p=0.025 Test results, a=0.05 H 0 : stationary populations, independent indicators
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12 Decide which combinations you like Impacted initial state do not stay here do not increase fishing impact p=0.950625
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13 Matrices can be converted to trees 0.0240.025 p=0.025 p=0.95 p=0.975 Deteriorating Not deteriorating 0.951 Not impacted initial state Deteriorating Not improving Improving 0.025.0006 Impacted initial state 0.900.024.0006
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14 More than 2 indicators: community level 0.023 0.0230.0480.0240.025 0.023 0.859 p=0.025 p=0.05 p=0.95 p=0.975 Deteriorating Not deteriorating 6.10 -4 Not impacted initial state do not increase fishing impact
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15 More than 2 indicators Impacted initial state do not stay here do not increase fishing impact Deteriorating Not improving Improving
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16 French surveys Vilaine Seine Somme
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17 Survey time-series Initial purpose: target fish species abundance indices / recruitment indices Consistent information on –target / non-target species –populations / communities Use for populations / community monitoring Comparative approach
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18 Indicators
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19 Results: Bay of Biscay population indicators 0 1 2 3 Anglerfish LOPHBUD 199019952000 0 2 4 LOPHPIS Average weight Monkfish Veined squidEuropean squid
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20 Bay of Biscay 1987 - 2004: slopes in ln(Abundance) = population growth rates
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21 Bay of Biscay 1987-2004 : slopes in size indicators, population level Average weight Slopes -0.30 -0.25 -0.20 -0.15 -0.10 -0.05 0.00 0.05 Average length Slopes -2.0 -1.5 -0.5 0.0 0.5 1.0
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22 Results: community indicators Bay of Biscay 199019952000 22.5 23.0 23.5 24.0 24.5 Total abundance ln(Abondance)
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23 Proportion of large fish threshold 26.66 cm P(stationary)= 0.001 199019952000 0.000 0.010 threshold 29.99 cm P(stationary)= 0.001
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24 Towards a diagnostic: Literature based initial state assessment 1982-2002 1995-2001 1987-2002 1997-2002 1999-2002 1990-2000 1995-2002 1997-2002 1995-2002
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25 Results: populations Deteriorating, p=0.0128 Deteriorating, p=0.0002 Not improving Stationary 11 pop. 43 pop. 22 pop. 51 pop.
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26 Results: initially not impacted communities Stationary, p(no change)=0.859 Vilaine, East Corsica
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27 Results: initially impacted communities Celtic Sea Deteriorating, p(no change)=0.021 Lions, Somme, Seine, S. North Sea, East. Channel Not improving, p(no change)=0.815 Bay of Biscay Not improving, p(no change)=0.021
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28 Results: summary
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29 Conclusions / Future developments Separate indicator estimation from diagnosis: desirable trends management objectives Importance of initial state assessment: improve methods (in relation to management objectives) Power and risk can be adjusted through risks of individual tests More indicators to refine interpretations Develop a taxonomy of expected fishing impacts
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30 Yearly standardized sampling since 1994 About 1100 stations observed from the Alboran Sea to the Aegean Sea, including Cyprus since 2005 More than 100 species studied More than 15 partners in 9 countries MEDITS SURVEY International bottom trawl survey in the Mediterranean Since 2002, priority action of the European regulation on fishery data collection in the Mediterranean
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31 Geographical areas 13 areas based on the GFCM management units 1 6 7 8 9 11 10 16 GFCM 15+16 17 18 19 20 22
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