Lack of big-bellied boys sparks pregnant pause: [1 All-round Country Edition]
Stapleton, John. The Australian; Canberra, A.C.T. [Canberra, A.C.T] 24 Nov 2004: 7.
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Abstract
The seahorses' struggle for survival is not limited to Tasmania, with the NSW Government announcing yesterday a new project to examine the effectiveness of using a system of marine parks to protect the species. NSW Department of Primary Industries conservation manager David Harasti said they would begin by monitoring the seahorses inside the Fly Point Aquatic Reserve at Port Stephens on the NSW central coast.
THE males of Tasmania puff out their brightly coloured pouches and pump them full of water, all the better to convince the circling females that they will make good fathers. Fights break out among the potential mates desperate to lay their eggs.
This is the exotic world of the "big-bellied" seahorses in the Derwent Estuary in Tasmania, where females outnumber males at least five to one. Their conduct here is even more striking because seahorses are normally monogamous.
The shortage of males may be the key to a dramatic plunge in the Derwent population, and to wildly fluctuating populations in other parts of the country, scientists believe. Seahorses are the only animal in the world of which the male becomes "pregnant".
Keith Martin-Smith, a leading scientist with global conservation group Project Seahorse, said the Tasmanian population had steadily declined since late 2000, an overall reduction of 75 per cent.
"Sex-ratio variations are of particular concern to the future populations as the male of the species is wholly responsible for pregnancy and birth," Dr Martin-Smith said. "This is unique in the animal kingdom. It is coming up to the breeding season. The males can afford to be choosey."
Once the male selects a partner, she will lay about 1000 eggs in his pouch. Sperm then runs down a duct into the pouch and thefertilised eggs become embedded in the skin of the pouch, where they hatch four weeks later. The problem for seahorses is their use in the alternative medicine field, with millions caught each year to be used to treat everything from asthma to impotence.
The seahorses' struggle for survival is not limited to Tasmania, with the NSW Government announcing yesterday a new project to examine the effectiveness of using a system of marine parks to protect the species. NSW Department of Primary Industries conservation manager David Harasti said they would begin by monitoring the seahorses inside the Fly Point Aquatic Reserve at Port Stephens on the NSW central coast.
"The taking of seahorses for any reason was banned in NSW in July and we are keen to determine whether the new protection is helping increase the population size," he said.
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