An analysis of nearly 30 years of data on African wildlife has uncovered a link between declining fish stocks and increased hunting and bush meat trade. The results suggest that when fish sources of protein wane, people turn toward illegal hunting on land, which can lead to species extinction.

Justin S. Brashares of the University of California at Berkeley and his colleagues studied animal census information collected between 1970 and 1998 by park rangers in Ghana and compared it to information collected about the fish supply in the region over the same time period. The researchers found a 76 percent drop in overall abundance for the 41 species studied, which included buffalo, antelope, jackal and lion. In particular, the team discovered that in years with a below average fish supply, there was a greater decline in the land animal populations. In addition, some smaller game reserves experienced local extinctions of nearly half the studied species.

The team also studied the sale of bush meat in 12 rural markets throughout Ghana in 1999 and found that poor fishing seasons were inversely related to both the price of fish and the amount of bush meat available for sale. Our study present very strong evidence showing how human food supply can be directly related to conservation of wildlife, Brashares says. We need people working together across disciplines to look at how losses of marine resources are impacting land resources and vice versa.