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Indicators for ecosystem based management: Methods and applications. Verena Trenkel, Anik Brind’Amour, Pascal Lorance, Stéphanie Mahevas, Marie-Joëlle Rochet Ecology and Models for Fisheries Science Ifremer, Nantes, France. Definition.
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Indicators for ecosystem based management: Methods and applications Verena Trenkel, Anik Brind’Amour, Pascal Lorance, Stéphanie Mahevas, Marie-Joëlle Rochet Ecology and Models for Fisheries Science Ifremer, Nantes, France
Definition An indicator is a variable which quantifies how well a human activity is managed, in relation to specified objectives. A structured suite of indicators will reveal important system changes.
Ecosystem based fisheries management Reduce quota Less fish Demand for food & wealth Fishing mortality Fish biomass
DPSIR framework Referencepoints, directions & enveloppes Objectives Response Impacts Pressures States Drivers
Referencepoints, directions & enveloppes Objectives Response Impacts Pressures States Drivers Indicator development Indicators Indicators Indicators Indicator development, selection, calculation, testing…
Referencepoints, directions & enveloppes Objectives Response Impacts Pressures States Drivers Methods development Methods Methods Methods Methods Methods Modelling pressure-state links, combining indicators, detecting trends, evaluating impacts…
Example: Developing food web indicators Morphometrics = diet & habitat Species type 1 Food web Position in water column Has the food web structure changed in the Mediterranean? 7 Functional groups
Example: Developing food web indicators Temporal changes in food webs Golf of Lions IonianSea AegeanSea
Ecological objective: Maintain pelagic food supply for higher trophic levels Knowledge Few top predators & piscivores have strong pelagic prey dependance Operational objectives Maintain herring and sprat in the Baltic Sea as prey for cod Maintain total forage fish biomass in North Sea State & impact indicators Prey biomass in critical area Proxy: predator condition/growth/productivity Reference level >x tons of prey species Pressure management TAC, effort control, escapement rules Example: Selecting indicators for pelagic ecosystems 10 10
Example: Simulation testing population indicators Spatial population dynamics Observations 2 4 1 Demographic rates Demographic rates Spatiotemporal catch & effort distribution r, K Spatiotemporal abundance distribution Depth Depth Indicator calculation 5 Fishery dynamics 3 Occupancy Effort Time Density Is occupancy a sensitive indicator for population abundance? In certain cases only: • occupancy can change much less than abundance • uncertainty in catches or effort can mask changes Trenkel et al In Press, Testing CPUE-derived spatial occupancy as an indicator for stock abundance: application to deep-sea stocks. Aquatic Living Resources DOI: 10.1051/alr/2013060 Trenkel et al In Press, Testing CPUE-derived spatial occupancy as an indicator for stock abundance: application to deep-sea stocks. Aquatic Living Resources DOI: 10.1051/alr/2013060 Trenkel et al In Press, Testing CPUE-derived spatial occupancy as an indicator for stock abundance: application to deep-sea stocks. Aquatic Living Resources DOI: 10.1051/alr/2013060
Example: Simulation testing management indicators Management scenarios + Uncertainties Model Indicators SENSITIVE to management? ROBUST to uncertainty? Which management indicators are sensitive and robust to uncertainty?
Example: Simulation testing management indicators Which management indicators are sensitive and robust to uncertainty? ECOMARS IBM Larvaire Spatial and seasonal distribution of populations Spatialized recruitment and natural mortality Mahévas et al. 2011 Vermard et al 2008 Spatial modelling of fisheries dynamicsLehuta et al 2010. IJMS & 2012. FR Huret et al. 2010. Spatial and seasonal distribution of fleets and economic behavior Pelletier et al 2009 Assessing indicator performance for management Lehuta et al 2013.
Do fishing pressure differences affect differentially fish community states? Example: Developing fishing pressure indicators
Do fishing pressure differences affect differentially fish community states? Example: Developing fishing pressure indicators Piscivores preferred High &selectiveremovals Diverse catch Fishing pressure varies in space & time, but differential impacts are difficult to detect
For more information on our work on indicators • Come and see me • Read our publications http://wwz.ifremer.fr/emh/Publications-EMH