Australian Great Whites are two distinct species: impact on conservation

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As reported in this article, despite inhabiting the same waters two populations of Great White sharks living in the coastal waters of Australia are genetically distinct, according to a new study published in the journal Marine Ecology Progress Series.

The two groups of Great Whites, or white sharks, are separated by the Bass Strait, a stretch of water between the Australian mainland and Tasmania to the south. Genetic tests from 97 shark tissue samples dating back to 1989 confirmed this geographical divide.

White shark numbers declined in the 20th century as a result of fishing and other human activities, resulting in the species now being protected in South Africa, the United States, Australia, New Zealand, and several other countries under the Convention on International Trade in Endangered Species (CITES).

The effectiveness of the CITES treaty and other white shark related conservation programs has been difficult to assess because of a lack of information on abundance, genetic diversity, reproductive behavior and population. The creature’s elusiveness forces marine biologists and government officials to classify them as vulnerable because they appear uncommon when compared with the distribution of similar species.

“The finding may indicate that individual populations of white sharks are more susceptible than previously thought to threats including fishing or changes in the local marine environment,” said Jennifer Ovenden from Australia’s Department of Agriculture, Fisheries and Forestry.

Fishermen target many species of sharks for their jaws, teeth, and fins; as it is considered a game fish. The great white shark, however, is rarely an object of commercial fishing or shark finners because of the steep penalties associated with their possession.

Murray W. Camp