FISH INDICATORS IN COASTAL ESTUARINE ECOSYSTEMS Main approaches along the French coasts
Anik Brind’Amour Ifremer Nantes, EMH
Jérémy Lobry Ifremer Nantes, EMH GIP Loire Estuaire 1 Introduction Indicator of what?
• Context (ex. EAF, WFD, EMS) →→ Indicators
• Ecosystemic and fish-based indicators assessing
– changes in exploited fish communities (ex. Rice 2003; Rochet and Trenkel 2003; Babcock et al. 2005; Clua et al. 2005; Shin et al. 2005; Methratta and Link 2006)
– ecological status of ecosystems (ex. Deegan et al. 1997; Harrison and Whitfield 2004; Breine et al. 2007; Coates et al. 2007)
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 1 Introduction Coastal areas
Global change (temperature, sea level…)
Urbanization Industry Chronic or/and punctual pollutions Agriculture (heavy metals, organic compounds) Shipping Fishing
www.tetes chercheuses.fr/.../ Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 1 Introduction
• Neither a review nor a validation • a subjective presentation of our Aim opinion based on results of several years of research in coastal areas (Demostem/STRADA)
1. Introduction 2. Case study 1. Combining indicator trends to assess ongoing changes in exploited fish Outline communities 2. Defining a multi-metric index to assess ecological status of transitional waters 3. Methodological elements 4. Discussion
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 2 Case study: assessing ongoing changes in exploited fish communities Time trends approach (Adapted from Rochet et al. 2005) • Dashboard-alike approach – Set of individual metrics or indicators – Interpretation framework for combining metrics
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 2 Case study: assessing ongoing changes in exploited fish communities Interpretation framework (e.g. mode-based metrics)
ln(N G0 ) ↑ L G0 ↔ ↓ ↑ GOOD RECRUITMENT FASTER GROWTH POOR RECRUITMENT FASTER GROWTH FASTER GROWTH More recruits of larger size Early spawning/spatial shift Early spawning/spatial shift Early spawning/spatial shift Suitable env. conditions Suitable env. conditions Suitable env. conditions ↔ GOOD RECRUITMENT POOR RECRUITMENT
Early spawning/spatial shift Early spawning Suitable env. conditions Unsuitable env. conditions GOOD RECRUITMENT SLOWER GROWTH POOR RECRUITMENT ↓ SLOWER GROWTH SLOWER GROWTH Late spawning/spatial shift Less recruits of smaller size Density dependence Late spawning/spatial shift Late spawning/spatial shift Suitable env. conditions Unsuitable env. conditions Unsuitable env. conditions
PotentialBrind’Amour human-induced & Lobry – EAF symposium – stress Boulogne sur Mer, 5-7 November 2008 2 Case study: assessing ongoing changes in exploited fish communities Time trends approach (Adapted from Rochet et al. 2005) • Dashboard-alike approach – Set of individual metrics or indicators – Interpretation framework for combining metrics – Reference state based on theoretical knowledge • Assessment of directions (i.e. linear trends) desired state
desirable reference state direction
referenceBrind’Amour & Lobry time – EAF symposium –current Boulogne sur time Mer, 5-7 November 2008 2 Case study: assessing ongoing changes in exploited fish communities Time trends approach (Adapted from Rochet et al. 2005) • Dashboard-alike approach – Set of individual metrics or indicators – Interpretation framework for combining metrics – Reference state based on theoretical knowledge • Assessment of directions (i.e. linear trends) – Combining the metrics: potential mechanisms • 2 by 2: population metrics • Successively: community metrics – Diagnostic according to the reference state
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 2 Case study: a MMI to assess ecological status of estuaries
NurseryEcological function of status estuaries Anthropogenic disturbances ΣΣΣ EcologicalPressure impact models functions ??
Step 1 – Proxy: fish metrics (beam trawl scale) Step 2 – Proxy: descriptors of contaminations
Step 3 – Variability due to the
sampling protocol (gear, press) in al., et (Courrat season, salinity, depth)
Step 4 – Variability due to estuarine features (estuarine size, ecoregion)
Step 5 – Estimation of the nursery function of each estuary
Step 6 – Link with the descriptors of contamination
Impact ofBrind’Amour anthropogenic & Lobry – EAF symposium disturbances – Boulogne sur Mer, 5-7 on November ecology 2008 2 Case study: a MMI to assess ecological status of estuaries MMI results 1 score by salinity class 2
2 1 Boundary 1 classes Log(densites)
2 0 1 Loire 0 Gironde
0.0 0.5 1.0 1.5 2.00 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Oligohaline Mesohaline Euhaline
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 2 Case study: a MMI to assess ecological status of estuaries MMI results
BMSM Seine Canch Bidas Chare Gironde Adour Somme Veys Authie Seudre Orne Loire Coues Risle e soa nte non CA 0,36 0,28 0,80 0,47 0,60 0,60 0,80 1,00 0,90 1,00 0,93 1,00 1,00 B 0,20 0,36 0,40 0,33 0,80 0,40 0,60 1,00 0,80 0,80 0,93 0,73 1,00 MJ 0,20 0,36 0,40 0,73 0,60 0,80 0,80 0,60 0,70 0,80 0,87 0,87 0,80 densitétotal 0,28 0,44 0,40 0,47 0,40 1,00 0,80 0,60 0,80 0,80 0,87 1,00 1,00 densitytotale Finalnote 0,26 0,36 0,50 0,50 0,60 0,70 0,75 0,80 0,80 0,85 0,90 0,90 0,95 finalescore Poor Good Very good Medium
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements Baseline
Mode-based → Population → Community Hierarchical metric
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements Candidate metrics
Case study
Metric Notation Frame. MMI Mode based indices
Average length for the first mode (G0) of population i L(G0)i,t x
ln-transformed population abundance for the first mode (G0) of ln(N) (G0)i,t x species i Population indices
ln-transformed population abundance for species i Li,t x
Biomass for species i Bi,t x
Community indices
Taxonomic-based indices
Diversity indices (Pielou’s evenness 1) J = x H/ln(S) Taxonomic diversity and distinctness indices ∆ and ∆* x Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 Case study
Metric Notation Frame. MMI Community indices
Taxonomic-free indices (Functional indices)
Total abundance in community Nt
Total biomass in community Bt
Total density in community DT x
Number of diadromous taxa CA x
Relative abundance of dependent taxa NDep x
2 Ratio of dependent taxa over independent taxa RDep/Indep x
Density of marine juveniles in community MJ x
Density of benthic fish in community B x
Discrete measures
3 Diversity of functional traits (Simpson index) FG Simp x Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements Baseline
Dashboard
Aggregative Combining method
Mode-based → Population → Community Hierarchical metric
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements Combining metrics 2 main methods
Multimetric Index Dashboard (MMI) – Set of individual – Suggested by WFD metrics or indicators – Weighted or not – Interpretation framework – Sum or … Strong theoretical In most cases not knowledge founded on ecological arguments
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements Baseline
Dashboard
Aggregative Indirect l Combining method e v e l Direct is s ly a n Mode-based → Population → Community A Hierarchical metric
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements
Analysing the response to pressure
Indicator, ok, but indicator of what? “an obvious requirement is that the indicators respond primarily to the anthropogenic activity being managed and are sufficiently sensitive that impacts of the activity and the responses to management action are clearly demonstrable.” (Greenstreet and Rogers 2006)
Direct methods Indirect methods
– Statistical models – Temporal or spatial gradient/evolution Strongly depends on – Concomitant trends data and descriptors Validation ?
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 3 Methodological elements Baseline
CS1 Dashboard
CS2 Aggregative Indirect l CombiningCombining method method e v e l Direct is s ly a n Mode-based → Population → Community A Hierarchical metric
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 4 Discussion Case study
• Both approaches are – Relevant regarding the context and objectives – Quantitative assessment ( precision )
• Complementary results – Regarding objectives • indirectly related to fishing pressure and other potential stresses affecting the recruitment and community structure • mainly focusing on heavy metal and organic contamination
• Different references – unknown initial state defined by expert knowledge – virtual reference conditions
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 4 Discussion Emergent characteristics
• Methodological convergence points
– Integration of functional aspects of fish communities (use of functional guilds)
– Gradient or contrasting states of pressure (on a geographical or temporal scale)
– Use of quantitative methods (statistical models)
– A certain degree of empiricism, such as expert judgement.
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 « LES INDICATEURS EN HALIEUTIQUE : PERTINENCE ET PRÉCISION »
9ème forum halieumétrique de l’AFH 30 juin – 2 juillet 2009, Bordeaux Acknowledgements
This study was partly supported by the European program IMAGE and the French research agency (ANR) under the project AMPHORE. The authors are grateful to the scientists and crews of the R.V. Gwen Drez who participated to the CS1 sampling cruises conducted between 2000 and 2005.
Results from the preliminary multimetric index developed in the Vilaine estuary are part of LITEAU scientific project founded by the French Water Agencies and the French Ministry in charge of Ecology and coordinated by the Cemagref (French Institute for Agricultural and Environmental engineering research). The authors want to acknowledge all the participant of the project. 1 Introduction Context
• Recent interrogations on functioning and ecological status of ecosystems – International conventions (Rio 1992 ; Cancun 1992 ; Jakarta 1995) • Change in fisheries management – Ecosystem Approach to Fisheries (FAO 1995) • Integrated diagnostic and IndicatorsIndicators monitoring tools – European Water Framework Directive (EU 2000) – European Marine Strategy Directive (EU 2008) • Ecosystem management tools – Marine Protected Areas
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 1 Introduction Fish as indicators Preferential positionPreferential position InterfaceInterface betweenbetween ManMan andand aquaticaquatic ecosystemsecosystems
High trophicHigh trophic level level Diversity of taxonomic groupsDiversity of taxonomic groups →→ integrateintegrate DiversityDiversity ofof morphological,morphological, ecologicalecological qualityquality ofof biological,biological, ecological,ecological, ecosystemecosystem andand behaviouralbehavioural and and functionalfunctional environmentenvironment characteristicscharacteristics
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 2 Case study The bay of Vilaine
– 220 km² under 20 m
B a y depth o f B is c – Watershed > 10,000 km² a y Bay of Vilaine – > 1,000,000 inhab. – Arzal dam since 1972
One of the main nursery grounds of the Bay of Biscay
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008 2 Case study: assessing ongoing changes in exploited fish communities Combining the metrics Population Community
Deteriorating Stationary
Rochet et al. (2005)
Brind’Amour & Lobry – EAF symposium – Boulogne sur Mer, 5-7 November 2008