Fishy Technique to Reduce Poaching

A technique used since the 1930s to estimate the abundance of fish has shown for the first time that enforcement patrols are effective at reducing poaching of elephants, African buffaloes and black rhinos in the Serengeti National Park in Tanzania.

The 5,700-square-mile Serengeti is one of Africa's most pristine preserves.

It's been impossible to actually count the number of animals that are poached because poaching is illegal and most animals--apart from elephants and rhinos which are traditionally not eaten--are caught in snares set by local villagers for their own use or sale.

"The estimates are just all over the place, not just for the Serengeti but all across Africa," said Ray Hilborn, University of Washington professor and lead author of a paper in the Nov. 24 issue of journal Science. This confounds efforts to learn how best to solve the problem when wildlife numbers decline catastrophically.

The researchers employed the catch-per-unit-of-effort technique used for decades by managers to estimate fish abundance and set fishing limits.

Estimates are based on a ratio comparing the number of fish caught in an area with the total number of hours of fishing--the unit-of-effort--by all the vessels in that area.

In the Serengeti, which has a 50-year-record of arrests and patrols, the scientists divided the number of poachers arrested by the number of patrols a day to estimate the amount of poaching. They assumed that arrests per patrol were representative of poaching intensity and not, for instance, that officer training or informant networks improved.

"We show that a precipitous decline in enforcement in 1977 resulted in a large increase in poaching and decline of many species," Hilborn and his co-authors wrote. "Conversely, expanded budgets and antipoaching patrols since the mid-1980s have significantly reduced poaching and allowed populations of buffalo, elephants and rhinoceros to rebuild."

---LiveScience Staff

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Credit: Felix Borner-www.wildlens.com/AAAS-Science