Living the Scientific Life (Scientist, Interrupted)

tags: coelacanth, Latimeria chalumnae, fish, living fossil, Indonesia

This past Saturday, a rare living fossil, the coelacanth, Latimeria chalumnae, was captured by fishhermen off the shores of Zanzibar. Zanzibar is an island archipelago comprised of numerous small islands and two large ones located 25-50 km off the coast of East Africa in the Indian Ocean. The coelacanth (pronounced SEE-la-kanth) is an ancient fish once thought to have become extinct at the time of the dinosaurs. You might also recall that another species of coelacanth was captured not too long ago, in May 2007, in Indonesia (pictured top).

The coelacanth is a lovely dark blue in color, fading to grey after death. Each fish has a distinctive pattern of pinkish-white spots that are distinct from one individual to the next. Their heavy bodies are covered with hard scales and toothy outgrowths that protect their bodies from rocks and predators. The coelacanth also have lobed fins and a peculiar three-lobed tail. The fish was originally known only from fossils that dated back 360 million years. It disappeared from the fossil record approximately 80 million years ago, so the animal was thought to be extinct until a specimen was unexpectedly captured off the coast of South Africa by a museum curator on a local fishing trawler in 1938. Since then, two closely-related species of coelacanth have been caught off the shores of five other countries: Comoros, Indonesia (this is a separate species, see link for story), Kenya, Madagascar and Mozambique.

Four fishermen caught the fish on Saturday, Nariman Jiddawi of the Institute of Marine Sciences, which is part of the University of Dar es Salaam in Tanzania's commercial capital. He added that the fish weighed 59.5 pounds (27 kg) and measured 4.4 feet (1.34 meters). An adult coelacanth can weigh as much as 98 kilograms and grow at least to 1.8 meters in length.

''Zanzibar will join a list of sites of having the rare fish caught in its own waters,'' said Jiddawi.

Mussa Aboud Jume, director of fisheries in Zanzibar, said that the coelacanth will be preserved and put on display in the Zanzibar Museum.

Since September 2003, 35 coelacanths have been caught in Mtwara, a southern region of Tanzania, and along the coast of Tanga in Tanzania's north, possibly because diminishing shallow water resources have forced fishermen to cast their nets into deeper waters where coelacanths live, experts say.

"Once we do not have trawlers, we don't get the coelacanths, it's as simple as that," observed Hassan Kolombo, a co-ordinator of the Tanga Coastal Zone Conservation and Development Program.

Trade in the coelacanth is banned under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

"I suppose we should be grateful to these trawlers, because they have revealed this amazing and unique fish population," said Solomon Makoloweka, also of the Tanga Coastal Zone Conservation and Development Program. He said they had been pressuring the Tanzanian government to limit trawlers' activities. "We are concerned they could destroy these precious things. We want the government to limit their activity and to help fund a proper research program so that we can learn more about the coelacanths and protect them."

Coelacanths are remarkable because of their limb-like fins that project away from their body and move in an alternating pattern, like legs. They also are the only living animal to have a fully functional intercranial joint, which is a bony division that separates its ear and brain from its nasal organs and eye. This joint gives them a powerful bite. They also give birth to live young.

Sources

NYTimes

MSNBC News