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Symposium on Integrating New Advances in Mediterranean Oceanography and Marine Biology. Session 5: Fisheries , Marine protected areas , population outbrusts , biodiversity shifts. An ExtendSim platform to simulate the effects of trawling on benthic communities. - PowerPoint PPT Presentation
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Alba Muntadas1*, Johanna Ballé-Béganton2, Michel Lample2, Silvia de Juan1, Denis Bailly2, Dolors Blasco1, Montserrat Demestre1
1Institut de Ciències del Mar, ICM-CSIC- Barcelona; 2Université de Bretagne Occidentale, UBO- Brest
An ExtendSim platform to simulate the effects of trawling on benthic communities
Session 5: Fisheries, Marine protected areas, population outbrusts, biodiversity shifts
Symposium on Integrating New Advances in Mediterranean Oceanography and Marine Biology
An ExtendSim platform to simulate the effects of trawling on benthic communities
BLOCKS
● SYSTEM PRESENTATION
● METHODOLOGY
● STUDY AREAS
● SIMULATION
PLATFORM: SIMULATION OF TRAWLING EFFECTS ON BENTHIC COMMUNITIES AND EXPLOITED RESOURCES
BLOCK : SYSTEM PRESENTATION
Benthos
Fishing effort
Commercial species Management
THE SYSTEM
[ Find out more ...]
This platform is meant to be a tool
to estimate the status of a community
subjected to a provided fishing
effort
● Trawling affects benthic communities modifying Essential Fish Habitats Effects on the resources.
● Platform goal link fishing – benthos – commercial species
● This platform is meant to be a useful tool for stakeholders: managers, fishermen, scientists, politicians…
Dayton et al. 1995. Aquatic Conservation. 5:205-232
-There are many ways to estimate fishing effort: CPUE, swept area, total length of trawl tracks..
Chosen unit:
GT x days at sea/month
- This information can be obtained in any area were the simulations wants to be applied
BLOCK : METHODOLOGYMETHOD
[ Find out more ...]
FISHING EFFORT ESTIMATION
Demestre et al. CIESM 2010
● Species composition is highly influenced by local characteristics it can mask fishing impact consequences
● SPECIES TRAITS : - Reduces the number of variables : Overcome regional differences Highlights fishing effects
● For the simulation we used simple traits easily assigned to species and directly related to trawling resistance/vulnerability
BLOCK : METHODOLOGYMETHOD
[ Find out more ...]
BENTHIC COMMUNITY REPRESENTATION : THE TRAITS APPROACH
de Juan, S. and Demestre, M. 2012. Ecological Indicators. 18: 183–190.
Traits used in the simulationPosition Feeding Motility Size Other attributesEmergent Filter
feedingSessile (attached)
Large>10 cm
Fragile
Surface Deposit feeding
Sedentary Medium5-10 cm
No protection
Surface burrowing
Predators Motile (crawlers)
Small<5cm
Flexible
Deep burrowing
Scavengers Highly motile (swimmers)
Strong
Regeneration
Vermiform
Hard shell
Legend Very resistant*
Resistant*
Vulnerable*
Very vulnerable*
* Vulnerability regarding to trawling
BLOCK : METHODOLOGYMETHOD
[ Find out more ...]
BENTHIC COMMUNITY REPRESENTATION : THE TRAITS APPROACH
BLOCK : STUDY SITES
-Presentation of the data available in each study site.
Community structure is presented by:
● Trait structure
● Species composition
STUDY AREAS
[ Find out more ...]
STUDY SITES
BLOCK : SIMULATION[ Find out more ...]
SIMULATION
PRESENT FISHING EFFORT 25000 GT * days at sea/month
HABITAT TYPE
● INPUTS
Mud > 80% Mud
60-70% Mud 40-30% Sand
DESIRED FISHING EFFORT 20000 GT * days at sea/month
Sandy-mud
Gravelly-mud
Sand
Sandy-gravel
Maërl
BLOCK : SIMULATION
-Total abundance-Percentage of trait categories within trait type
PLOTPLOT
RESET
[ Find out more ...]
SIMULATION
SIMULATION OUTPUT : PRESENT VS DESIRED EFFORT STRUCTURE
Uncertainity of
the simulation
Actual statusStructure at desired effort
BLOCK : SIMULATION[ Find out more ...]
SIMULATION
SIMULATION OUTPUT : PRESENT VS DESIRED EFFORT STRUCTURE
Scav
engi
ng
Size
Feeding
Size
Feeding
Large
Medium
Small
Filte
rfe
edin
g
Depo
sitfe
edin
g
Scav
engi
ng
Pred
ator
PRESENT STRUCTURE STRUCTURE AT DESIRED EFFORT
Large
Medium
Small
Filte
rfe
edin
g
Depo
sitfe
edin
g
Pred
ator
Relationship between traits: - Possibility to show one selected trait against another trait
An ExtendSim platform to simulate the effects of trawling on benthic communities
WORK STATUS
● DONE: -Epifauna and physical data collection -Platform structure ● IN PROGRESS: -Statistical basis to run the simulation -Building the graphical interface
FUTURE CHALLENGES : - Include information on infaunal community - Include the link benthos – comercial species
