Chers visiteurs,
j' ai eu des nouvelles
de la biologiste marine et spécialiste de
l’halieutique Lyne Morissette, qui m'a
envoyé son second article, un an apres son
premier (voir "Article
de Lyne Morissete" (mars 2009)).
Il
est intitulé :
Ecosystem
models clarify the trophic role of whales off Northwest
Africa.
ABSTRACT: There
is global concern about the interaction between
whales and fisheries, and in some countries, great
whales are viewed as a threat to fisheries by potentially
eating fish species that could be exploited for
human consumption. We developed an ecosystem model
to explore the trophic interactions between cetaceans
and fisheries off Northwest Africa and to examine
the potential impact of a reduction in the abundance
of baleen whales on fishery yields. This allowed
us to characterize the structure and function of
the ecosystem in terms of biomass, mortalities,
consumption rates, food habits, and fisheries. Faced
with sparse data for our study area, we explicitly
accounted for uncertainty in ecosystem structure,
model accuracy, and input data and conducted an
extensive sensitivity analysis. We tested model
performance with time series of biomass and catches
for important species of the system. Our results
indicate that the overlap between prey species consumed
by cetaceans and species targeted in fisheries is
low. Furthermore, for a wide range of assumptions
about whale abundances, diet composition, and food
consumption in breeding areas, we found that whale
consumption is several orders of magnitude lower
than total fishery catches and 2 orders of magnitude
lower than the amounts taken by other trophic groups.
Finally, simulations of substantial reductions of
whale populations did not influence the biomass
of commercially important fish, nor any other species
of the foodweb. These results suggest that fisheries
yields would not benefit from the removal of whales
in this area.
Pour lire le rapport,
vous pouvez la contacter directement: lyne.morissette@globetrotter.net
Bonne lecture !
Cordialement. Julien Marchal. Canada.
Avril 2010.
