Science and Nature

Tigers of Rajasthan 'disappear'

A massive search for tigers in a wildlife reserve in India's western state of Rajasthan has failed to find firm evidence any of them are alive. Three hundred forestry workers spent two weeks looking for tiger paw prints in the Sariska reserve, set up in 1979 as part of a tiger conservation scheme. Environmentalists say 15 tigers counted there last May have disappeared.

India is estimated to have more than 3,000 tigers, accounting for about half the world's tiger population. Trapping Forestry officials told the BBC they were hopeful they might still find tigers during a census planned for May. Since last May's count, traps have been found in the forest.

The environmentalists say mining in the area is also destroying the tigers' habitat.

Prominent social worker Rajendar Singh said conservation measures had increased tiger numbers to 20 by 2001 but said officials had failed to react to the danger of trapping.

http://news.bbc.co.uk/2/hi/south_asia/4270845.stm

Limit portions of farm-raised salmon, experts say

Alison McCook

NEW YORK (Reuters Health) - People should avoid eating too much farm-raised salmon, which contains significantly more of the chemical dioxin than is found in fish caught in the wild, new study findings show.

After analyzing the dioxin content of farm-raised and wild salmon captured in different regions, a group of North American researchers found that farm-raised types contain between 3 and 10 times more dioxin than wild salmon.

Using guidelines from the World Health Organization, the researchers calculate that consumers should eat fewer than 10 meals of farm-raised salmon per month, and limit fish that's raised on northern European farms to 4 times per month.

Lead author of the study in the journal Environmental Health Perspectives, Dr. Jeffery A. Foran, noted that essentially all salmon that's not specifically labeled "wild" has likely been raised on a farm.

He added that farm-raised salmon contains higher concentrations of other toxic chemicals, including polychlorinated biphenyls (PCBs), toxaphene and dieldrin. And if consumers really want to be safe and avoid harm from all types of chemicals, they should follow "even more stringent" limits on salmon consumption.

"In essence, people should avoid eating farmed salmon," said Foran of the Midwest Center for Environmental Science and Public Policy in Milwaukee, Wisconsin, in an interview.

There's plenty of research indicating that it's healthy to eat oily fish such as salmon, which is rich in the omega-3 fatty acids that can prevent heart disease and other major killers. However, fish also accumulate a variety of toxic environmental pollutants, which may put people at risk of additional health problems.

Currently, more than half of salmon sold in the world was raised on a farm, Foran and his team note. To investigate whether farm-raised salmon has more dioxin than salmon captured in the wild, the researchers tested salmon from different farming regions and wild salmon captured in various waters.

"There is considerably more of those contaminants in the farm-raised salmon," Foran said.

He explained that farm-raised salmon contains more dioxin because the chemical is concentrated in fatty fish feed, made up of fishmeal and fish oil. Farm-raised salmon are fed vast amounts of feed so they will grow quickly, he said, giving them a "supersized dose" of dioxin.

SOURCE: Environmental Health Perspectives, May 2005.