[MARMAM] New publication on the "whales eat fish" issue in Science

Lyne Morissette lyne.morissette at globetrotter.net
Fri Feb 13 11:51:53 PST 2009


Scientists Conclude That Culling Whales Will Not Help Fisheries
in Tropical Regions
Science Article Weighs In on International Whaling Commission Debate

WASHINGTON - Culling whales will not increase fisheries catches in  
tropical waters, according to a new paper supported by the Lenfest  
Ocean Program and published today in the journal Science. For years,  
Japan has argued that reducing the number of baleen whales in the  
oceans would improve fisheries because whales eat fish that are caught  
for human consumption. The study published today found that even a  
complete eradication of whale populations in tropical waters would not  
lead to any significant increase in fish populations.

Many countries in Western Africa and the Caribbean have been persuaded  
by Japan to join the International Whaling Commission (IWC) and vote  
in favor of resuming commercial whaling with the understanding that  
culling whales would result in increased fisheries catches.
“Our models unequivocally show that removing whales would not  
significantly increase the amount of commercially valuable fish,” said  
Dr. Leah Gerber, lead author and associate professor of Ecology,  
Evolution and Environmental Science at Arizona State University.  
“Instead, we found that fishing is having a far greater bearing on the  
health of the fish stocks in the region. Interestingly, when whales  
were more abundant before World War II, the fisheries were in good  
shape.”

“The assertion that whales are competing with fisheries for food is,  
on the surface, very persuasive, because it seems intuitive that these  
large animals must be consuming enormous amounts of food,” said Dr.  
Kristin Kaschner, an author based at the Evolutionary Biology and  
Ecology Lab at the University of Freiburg, Germany. “However,  
competition within ecosystems is a complex issue and needs to be  
investigated using the appropriate scientific tools.”
The authors constructed ecosystem models, which account for feeding  
interactions between whales and fish, to understand the role that  
baleen whales play in tropical marine ecosystems in Western Africa and  
the Caribbean, where baleen whales are known to breed. The scientists  
used global and regional data, validated through scientific workshops  
in Senegal and Barbados, to determine whether competition was occurring.

“An ocean ecosystem is greater than the sum of its parts. Removing  
whales from the equation does not increase the number of fish and  
impacts the health of the overall system,” said Dr. Lyne Morissette,  
an author based at the Institut des Sciences de la Mer de Rimouski,  
Canada. “We
need to focus on truly effective and sustainable management approaches  
to recover our fisheries.”
The researchers suggest these results underscore the important role of  
science in policy decisions about whales and fisheries interactions.  
They also emphasize that the goal of ecosystem-based management should  
not be to manipulate individual components of food webs in an attempt  
to maximize the amount of fish to catch, but to manage the whole  
system for long-term sustainability.

“All countries should adopt leadership roles in a common effort to  
manage our fisheries better,” said Dr. Daniel Pauly, an author from  
the University of British Columbia. “The assertion that fish supply is  
in peril is legitimate, but the problem is resolved with better  
management, not whaling.”

For additional information, including the access to the full version  
of this Science article, visit www.lenfestocean.org/whales_fisheries.html

Lyne Morissette,  Ph.D.
Institut des Sciences de la Mer de Rimouski (ISMER)
310, allée des Ursulines, C.P. 3300
Rimouski, QC
G5L 3A1
(418) 723-1986, ext. 1981
lyne.morissette at globetrotter.net

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