Dear All,
The following article has just been published in MEPS:
Piroddi, C., Bearzi, G., Christensen, V. 2011. Marine open cage aquaculture in
the eastern Mediterranean Sea: a new trophic resourcefor bottlenose dolphins.
ABSTRACT: Over the last 2 decades marine open cage aquaculture in the
Mediterranean Sea has
grown rapidly, leading to increased productivity in the water column near fish
farms. Here we
investigated the effect of such increase in productivity on the common
bottlenose dolphin Tursiops
truncatus. We developed an ecosystem model for the inner Ionian Sea
Archipelago, western
Greece, to: (1) evaluate the trophic interactions between bottlenose dolphins
and their surrounding
ecosystem, including cage-associated organisms; (2) investigate simultaneously
3 hypotheses
that could explain bottlenose dolphin dynamics: (a) increasing fishing effort
and changes in ocean
productivity, (b) competition with other species, and (c) increase in number of
fish farms; and
(3) explore spatial trends in bottlenose dolphins distribution using the
increased number of fish
farms as an explanatory variable. Comparisons of model predictions with
historical time-series
data indicate that only the increase in number of cages and thereby in
productivity near fish farms
contributed to the trends observed in dolphin numbers. Spatial analysis also
confirmed an
increase in occurrence of these dolphins in the proximity of the farms. These
outcomes suggest
that high productivity in waters surrounding fish cages—within a coastal area
that is markedly
oligotrophic—may attract bottlenose dolphins. The present study shows that open
cage aquaculture
has benefited bottlenose dolphins by easing their way of catching prey. Further
studies
should be conducted in other areas of the Mediterranean Sea to investigate
whether the higher
occurrence of bottlenose dolphins around fish cages is a common pattern and if
it is driven by the
trophic status of the ecosystem or by the type of fishes that surround the
cages.
KEY WORDS: Bottlenose dolphin · Fish farms · Ionian Sea · Ecosystem modelling
approach
PDF copy can be downloaded from the journal website:
http://www.int-res.com/articles/meps2011/440/m440p255.pdf
or you can request a copy by emailing me at: [email protected]
Best Regards,
Chiara
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