Large animals in 'double jeopardy' of extinction

Large animals hunted for their parts -- such as elephant ivory and shark fins -- are in double jeopardy of extinction due to their large body size and high value, says a study.

The study reveals underappreciated risk to marine species similar to that of iconic terrestrial species.

"We typically assume that if a species is reduced to low numbers, individuals will be hard to find, hunters will stop hunting, and populations will be given a chance to recover," said one of the researchers Loren McClenachan of Colby College in Waterville, Maine, US.

"But the extreme values of these species mean that without significant conservation intervention, they will be hunted to extinction," McClenachan noted.

In the new study, the researchers identified a taxonomically diverse group of more than 100 large marine and terrestrial species that are targeted for international luxury markets.

They estimated the value of these species across three points of sale and explored the relationships among extinction risk, value, and body size.

The analysis showed a threshold above which economic value is the key driver of extinction risk.

Although lower-value species are influenced primarily by their biology, the most valuable species are at high risk of extinction no matter their size.

Once mean product values are greater than $12,557 per kilogram, body size no longer drives risk, the report showed.

The researchers also uncovered important differences between marine and terrestrial species that point to elevated risk in the sea.

Although marine products are generally less valuable on a per kilogram basis, individual animals are still just as valuable as the most valuable terrestrial species.

An individual whale shark, for example, is about as valuable as the most valuable terrestrial species: rhinoceroses and tigers.

The risk to marine species is not reduced for species with larger ranges as it is on land, either, the researchers said.

The findings appeared in the journal Current Biology.

--IANS

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