Bushmeat includes game such as antelope but also species such as monkeys and jackals.

The finding, published in the journal Science, confirms accusations from local conservation groups that international fishing is hurting local people.

"This study provides the strongest link yet between a local fish supply with immediate, dramatic effects on bushmeat hunting and terrestrial wildlife," said Justin Brashares, an assistant professor of ecosystem sciences at the University of California Berkeley who led the study.

"If people aren't able to get their protein from fish, they'll turn elsewhere for food and economic survival. Unfortunately, the impacts on wild game resources are not sustainable, and species are literally disappearing from the reserves," Brashares added in a statement.

The result can be devastating, socially and economically, the researchers said. "Recent collapses of mammal populations in some areas of West Africa have been linked to geographic patterns of poverty and malnourishment," they wrote.

European Union subsidies of European fleets may be in part to blame. "If it weren't for this financial support, these studies suggest, it wouldn't be worthwhile for EU fleets to head to West Africa," he said.

More than half of Ghana's 20 million people live near the coast and they rely heavily on fishing.

Brashares and colleagues said they studied census data recorded by park rangers from 1970 to 1998 for 41 species of animals such as buffalo, antelope, jackals, lions, elephants, monkeys and baboons.

Then they analyzed data from the United Nations Food and Agriculture Organization on fish in the region.

They found a 76 percent decrease in numbers of mammals, with many local extinctions.

The fewer fish there were year to year, the harder the impact on land animals, they found. Checks on local market prices confirmed the suspicions.

"The fact that fish prices were high when fish availability was low indicates that the link with high bushmeat sales was driven by low fish supply," said Andrew Balmford, a conservation biologist at Britain's University of Cambridge who worked on the report.

"Our results emphasize the urgent need to develop cheap protein alternatives to bushmeat and to improve fisheries management by foreign and domestic fleets to avert extinctions of tropical wildlife," the researchers concluded.

Bushmeat hunting has also been linked to the emergence of dangerous new viruses that may have jumped from animals to people -- Ebola and the AIDS virus.

The researchers noted that the European Union heavily fishes off the African coast, with financial subsidies for fleets rising to more than $350 million in 2001 from $6 million in 1981.

Some conservation experts say that the fish licensing agreements between several African nations and the European Union and other industrialized nations heavily favor the rich nations.

"These agreements are extremely unfair," said Daniel Pauly, professor and director of the Fisheries Center at Canada's University of British Columbia, who did not work on the study.