By Richard Black
Environment correspondent, BBC News website, Santiago, Chile
Demonstrations are common during IWC meetings
A coalition of conservation groups and a leading fisheries scientist have accused Japan of damaging the fisheries interests of poorer countries.
They say Japan promotes the argument that whales are responsible for declining fish stocks in order to boost support for whale hunting.
They say this stops poor countries from focussing on real causes of decline.
A spokesman for Japan's whale research institution described the accusation as "absurd and irresponsible".
The groups involved presented their conclusions on the sidelines of the International Whaling Commission (IWC) annual meeting.
Daniel Pauly, director of the University of British Columbia Fisheries Centre, said there was abundant evidence that whales are not behind the decline in fish stocks.
"Blaming whales is an issue that is not only false - whales are no more responsible than the Martians - but which prevents the very small resources of West African countries from being devoted to understanding the real reasons why their fisheries are declining," he said.
Decline and fall
There is little doubt that fish stocks globally are shrinking. One recent major study projected there would be no commercial fisheries left in 50 years if current trends continued.
Some developing countries, notably along the west coast of Africa, have seen stocks fall abruptly as fleets from Europe and East Asia have moved either legally or illegally into grounds that had previously been the preserve of small scale local fishermen.
But some of these countries evidently believe the fish are disappearing largely because whales are eating them.
In February, a group of 11 African countries - all members of the IWC - published conclusions from a workshop held in Rabat, Morocco, at which senior Japanese whaling officials were present, referring to "the natural competition existing between whale species and (human) populations of developing countries in regard to utilisation of living marine resources".
Dr Pauly said that focussing on whales diverted attention from the real causes of depletion.
"In some countries, a fisheries division would consist of just five or six people; and if their minister comes along and says 'it's the whales', how are they going to be motivated to look for illegal fishing, to look at the access agreements (signed with European or Asian governments) that feed back only 1% of the value of the fish landed?"
In a paper written for the IWC meeting, Dr Pauly argues that whales cannot be a significant cause of fisheries decline because in the past, numbers of both whales and fish were much higher than they are now.
He also cites evidence assembled in the 1990s showing that only about 1% of the food eaten by any group of marine mammals was taken in areas home to important fisheries for human consumption.
Dan Goodman, a councillor to Japan's Institute of Cetacean Research which manages the nation's scientific whaling programme, said Japan had never said that whales were the cause of declining fish stocks.
However, he told BBC News: "In the western North Pacific off the coast of Japan, whales are eating large quantities of at least 10 species that are the target of commercial fisheries; some of these stocks have significantly declined.
"What the Japanese Government has been saying is that their research, as well as research done by Norway and Iceland, clearly indicates that at least for some areas whales do consume large quantities of fish and that interactions between whales and fisheries need to be addressed in ecosystem approaches to management."
Mr Goodman also dismissed as "an absurd allegation and a gross misrepresentation" the notion that Japan can be held responsible for how African countries address overfishing in their waters.
But Remi Parmentier from the Pew Environment Group said Japan has been raising the issue "to scare and recruit countries into supporting its move to end the (whaling) moratorium."
There was now so much evidence against the "whales eat fish" argument that it should, he said, now be closed.