Ancient endangered giant fish numbers growing-sturgeon

“Worldwide, most species of large freshwater fish are in danger of going extinct in the near future,” said Hogan, a National Geographic emerging explorer.081112-biggest-fish_big

“The white sturgeon seems to have avoided the fate of species like the Chinese paddlefish of the Yangtze River and the critically endangered giant catfish of the Mekong River.”

When dozens of white female sturgeon began washing up dead on the banks of British Columbia’s Fraser River in the mid-1990s, some feared that North America’s largest freshwater fish could be headed toward extinction. That’s when an alliance of government agencies, environmentalists, aboriginal groups, and commercial and recreational fishers came together to save the sturgeon, spurring a robust recovery of the lower Fraser River population. (1)

One of the oldest families of bony fish in existence, they are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. They are distinctive for their elongated bodies, lack of scales, and occasional great size: Sturgeons ranging from 7–12 feet (2-3½ m) in length are common, and some species grow up to 18 feet (5.5 m). Most sturgeons are anadromous bottom-feeders, spawning upstream and feeding in river deltas and estuaries. While some are entirely freshwater, very few venture into the open ocean beyond near coastal areas.
Sturgeon have been referred to as both the Leviathans and Methuselahs of freshwater fish. They are among the largest fish: some beluga (Huso huso) in the Caspian Sea reportedly attain over 5.5 m and 2000 kg while for kaluga (H. dauricus) in the Amur River similar lengths and over 1000 kg weights have been reported. They are also probably the longest-lived of the fishes, some living well over 100 years and attaining sexual maturity at 20 years or more. The combination of slow growth and reproductive rates and the extremely high value placed on mature egg-bearing females make sturgeon particularly vulnerable to overfishing.

Several species of sturgeons are harvested for their roe, which is made into caviar – a luxury good which makes some sturgeons pound for pound the most valuable of all harvested fish. Because they are slow-growing and mature very late in life, they are particularly vulnerable to exploitation and to other threats, including pollution and habitat fragmentation. Most species of sturgeons are currently considered either vulnerable, endangered or critically endangered. (2)

Sturgeon (and, therefore also the caviar trade) are under severe threat from overfishing, poaching and water pollution.slide1ss2-lgwhite-sturg
1. Excerpts from Giant Prehistoric Fish Rebounding in Canada – Stefan Lovgren in Chilliwack, Canada
National Geographic News   November 13, 2008

http://news.nationalgeographic.com/news/2008/11/081112-biggest-fish.html?source=email_wn_20081121&email=wn

2. Excerpts from   http://en.wikipedia.org/wiki/White_sturgeon
Image courtesy of http://en.wikipedia.org/wiki/Image:Sturgeon.jpg#file

Video giant sturgeon
http://www.youtube.com/watch?v=t6d2C3d6MJA

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