Thu, Aug 07, 2008 - Page 2 News List

Rare salmon thrive in new homes

BATTLE TO SURVIVEWuling Formosan Landlocked Salmon Conservation Center researchers say their efforts to save the endangered fish are beginning to pay off

STAFF WRITER, WITH CNA

A Formosan landlocked salmon is pictured in a river on Dec. 11 last year. After four years of research, it has been found that water temperatures and flow rates are the most important factors decreasing the risk of the extinction of the fish.

PHOTO COURTESY OF LIAO LIN-YAN

Much to the excitement of local researchers, artificially raised Formosan landlocked salmon — a critically endangered species — has been successfully breeding since being introduced into new habitats in the wild, an ichthyologist said on Tuesday.

Researchers from the Wuling Formosan Landlocked Salmon Conservation Center in Sheipa National Park (雪霸國家公園) in central Taiwan have released about 1,000 artificially bred rare salmon into the Sihjielan River (司界蘭溪) and Nanhu River (南湖溪) over the past two years.

Center director Liao Lin-yan (廖林彥) said a new generation of Formosan landlocked salmon, numbering about 80 to 90, were seen swimming in Sihjielan River in June.

“It marks the first time that the rare fish — a holdover from the last Ice Age — has survived and reproduced in a new habitat,” Liao said.

In the past, the fish could only be found in the Cijiawan River (七家灣溪), a protected sanctuary for the Formosan landlocked salmon in the park.

In Nanhu River, Liao said, only previously released salmon bearing identification tags have been seen so far, which meant they had yet to spawn.

The migration of the rare fish, however, has provoked mixed reactions, with opponents saying the species should not be propagated in a location where the fish has not previously been documented, while proponents say migration is vital to preserve the salmon.

Liao said the center was neutral on the matter and that its main concern was conservation of the center’s water supply.

“As the water in Cijiawan River tends to be very turbid following typhoons, the conservation center needs to store water in advance to ensure that fry being raised there can survive,” Liao said.

Although the environmental devastation caused by rampant overcultivation of orchards and vegetable farms in the nearby Wuling Farm area has been brought under control, landslides in the upper reaches of the river continue to occur, causing serious turbidity downstream in the wake of typhoons or heavy rain, Liao said.

Without a large storage pond, the water supply is often insufficient, Liao said, adding that the center was considering drilling wells as a secondary water source.

Meanwhile, Liao said that although the park had built a special structure in which the rare fish can take refuge in emergencies, the population still suffers a steep decline after every rainstorm or typhoon.

“The number of salmon in Cijiawan River has declined by about 25 percent to some 1,500, because of Tropical Storm Kamaelgi and Typhoon Fung-wong,” he said.

The Formosan landlocked salmon, or Oncorhynchus masou formosanus, is a subspecies of the seema, which is also found in Taiwan. It is critically endangered and was once classified as facing a high risk of extinction.

As a result of overfishing, there were about 400 salmon left before efforts to protect them were launched. Today, their biggest enemy is pollution, as the fish requires very clean and cold water to thrive.

The salmon became landlocked during the last glacial epoch and its discovery in Taiwan is considered a biological miracle.

Formosan landlocked salmon grow to about 30cm in length and inhabit cold, slow-flowing streams with gently sloping beds at elevations above 1,500m, such as the Cijiawan River in the upper reaches of Tachia River (大甲溪).

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