Transcript Main exploited ecosystems in the GFCM area

Main exploited ecosystems
in the GFCM area
An attempt of classification
Jordi Lleonart
FAO
Ecosystem
A spatio-temporal system of the biosphere,
including its living components (plants,
animals, micro-organisms) and the nonliving components of their environment, with
their relationships, as determined by past
and present environmental forcing functions
and interactions amongst biota.
(one of the many definitions)
Large Marine Ecosystem
• Large Marine Ecosystems (LMEs) are regions of
ocean and coastal space that encompass river
basins and estuaries and extend out to the seaward
boundary of continental shelves and the seaward
margins of coastal current systems.
• LMEs are characterized by distinct bathymetry,
hydrology, productivity and trophic interactions.
• 64 LMEs currently identified in the World
• The GFCM area of competence includes two LMEs:
– The Mediterranean sea (LME # 26)
– Black sea (LME # 62)
Identifying ecosystems in the
Mediterranean sea
Geographical criteria
• 10 Statistical divisions
(FAO)
• 30 Geographical
Subareas (GFCM)
Identifying ecosystems in the
Mediterranean sea
Ecological criteria
• Related to the bottom
– Pelagic (including
plankton)
– Demersal or benthic
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Soft bottoms
Rocky bottoms
Coralligenous
Seagrass beds
• Related to the coast
– Littoral (including
estuaries and lagoons)
– Neritic
– Oceanic
• Related to depth
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Coastal or littoral
Shelf
Slope
Deep sea
A possible classification
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Pelagic, shelf
Pelagic oceanic
Coastal or littoral
Demersal, shelf, soft bottoms
Demersal, shelf, hard bottoms
Demersal, slope
Demersal, deep sea
Pelagic, shelf (neritic?)
• Target species
– Mainly small pelagics
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Sardine
Anchovy
Sardinella
Spratt
• Other species
• Fishing gears
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Purse seine
Pelagic trawl
Towed gear
Small driftnets
• Impacts of fishing
– Fishing of postlarvae
and juveniles
– Overfishing
• Other impacts
Pelagic, oceanic
• Target Species
– Mainly large pelagics
• Tuna and tuna like
• Dolphinfish
• Pelagic sharks
• Non-target species
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Pelagic sharks
Turtles
Cetaceans
Birds
• Fishing gears
– Drifnets
– Longlines
– Seines
• Impacts of fishing
– Mortality of non-target
species
– Overfishing
• Other impacts
Coastal or littoral
• Target species
– Many
• Non target species
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Monk seal
Turtles
Patellidae & other
Seagrass
Juveniles of many
species
• Fishing gears
– Many (even forbidden)
• Impacts of fishing
– Fishing of juveniles
– Habitat destruction
• Other impacts
– Habitat destruction by
• Tourism
• Pollution
• Infrastructures
Demersal, shelf, soft bottoms
• Target species
– Many bony fish
– Shellfish
• Non-target species
– Seagrass
• Fishing gears
– Towed gears
– Nets
– Pots
• Impacts of fishing
– Ghost fishing (nets)
– Habitat destruction by
towed gears
• Other impacts
Demersal, shelf, hard bottoms
• Target species
– Many bony fish
– Corals
• Non-target species
– Corals
• Fishing gear
– Towed gears
• Impacts of fishing
– Poor selectivity
– Habitat destruction by
towed gears
– Ghost fishing
• Other impacts
Demersal, slope
• Target species
• Fishing gears
– Shrimps
– Large hake
– Trawl
– Pots
– Longline
• Non-target species
• Impacts of fishing
– Poor selectivity
– Overfishing
• Other impacts
Demersal, deep sea
• Target species
– Shrimps
• Aristeus antennatus
• Aristeomorpha foliacea
– Other species
• Non-target species
• Alepocephalus
rostratus
• Etc.
• Fishing gears
– Trawl
– Pots
• Impacts of fishing
– Habitat destruction
– Community changes
• Other impacts
– Waste
From 2005 “Members of the GFCM shall prohibit
the use of towed dredges and trawlnets fisheries at
depths beyond 1 000 m of depth”
Principles of relevance to an ecosystem
approach to fisheries (EAF)
FAO Technical Guidelines for Responsible Fisheries 4(suppl. 2)
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Avoiding overfishing
Ensuring reversibility and rebuilding
Minimizing fisheries impact
Considering species interactions
Ensuring compatibility (of legislations)
Applying the precautionary approach
Improving human well-being and equity
Allocating user rights
Promoting sectoral integration
Broadening stakeholders participation
Maintaining ecosystem integrity
Avoiding overfishing
• Overfishing affects almost all
Mediterranean exploited ecosystems
– Growth overfishing → improve selectivity
– Recruitment overfishing → allow reproduction
– Ecosystem overexploitation → decrease
bycatch, discards, harmful gears. Maintain
community structures.
– In general: decrease F. Since F=q∙E, it means
decreasing q and/or E
Ensuring reversibility and rebuilding
• Irreversible changes affect mainly the
coastal and shallow ecosystems: seagrass
and coraligenous [towed gears in sensitive
areas]
• Effectively protect endangered species
(turtles, mammals, birds, sharks, and
some other apical predators) [driftnets and
surface longlines]
Minimizing fisheries impact
• Objective: remove only the target species
minimizing:
– Discards
– By catch
– Degradation of sensitive bottoms
– Other induced mortality (ghost fishing)
• Note: the points above are tautological,
since they are consequences, not causes,
of overfishing
Considering species interactions
• Trophic relationships are networks, not
lines. The model
“one predator – one prey”, so if we want the
prey, the predator is our competitor, just kill it
is too simple and does not work. Things are
more complex (i.e. the predator can also
feed on other predators or competitors of
the prey).
• Research (data and modelling) is needed
Applying the precautionary
approach
Complexity
Irreversible processes
Uncertainty
Difficulties of forecasting
Danger to damage
the ecosystem
Instruments
• Control selectivity and sizes
• Regulate OU’s (fleets and gears)
– Limit the effort
– Eradicate damaging and aggressive gears
(i.e. towed gears in sensitive areas)
– Eradicate IUU fishing
• Control areas
– Closures
– Implementing MPA’s
More instruments
• Scientific research
– Getting data
• Catch and effort
• Biology and environment
– Developping ecosystemic models, indicators
and reference points
• Stakeholders participation in an adaptive
management framework
• Enforcement of the existing rules
Final considerations (1)
• Facing overfishing1
– Let them grow
– Let them spawn
– Let the mega-spawners (BOFF) live
• Protecting ecosystem
– Maintain habitats
– Maintain trophic pathways
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1 Froese,
R.- 2004. Keep it simple: three indicators to deal with overfishing.
Fish and fisheries, 5:86-91
Final considerations (and 2)
• Fisheries management (TROM, EAF or
whatever) does not mean not fishing, but
fishing better.
• The Mediterranean, and its fisheries, are
complex systems, but research, advice
and management are possible and they
work (as it has been demonstrated).
FTP sites
• SCMEE
http://www.cmima.csic.es/pub/SCMEE
• SCSA
ftp://cucafera.icm.csic.es/pub/SCSA