Whats seven feet long, 250 million years old, and currently lurking in the depths of Oregons Rogue River? Its the green sturgeon, the craggy, shark-like fish that has quietly eked out a living since the time of the dinosaurs. But according to a new study published by researchers from the Bronx-Zoo based Wildlife Conservation Society and other groups, this living fossil is extremely vulnerable to both overfishing and habitat alteration such as water diversion for irrigation and pollution. The study appears in the current issue of the Journal of Applied Ichthyology.
Using radio-tracking techniques, the authors of the study found that once green sturgeon enter freshwater rivers to spawn they spend long periods of time in extremely small home ranges -- sometimes just a 50-by-50 yard pool -- shared by numbers of individuals. This, coupled with the fact that the fish breeds in just three North American rivers, including the Rogue in Oregon, and the Klamath and Sacramento in California, makes it particularly sensitive to human impacts.
"This study shows that green sturgeon can easily become the victims of human exploitation and habitat loss," said Wildlife Conservation Society biologist Dan Erickson, the lead author of the study. "Precautionary management measures, such as the current sport-fishing regulations in the Rogue, may be justified to protect populations throughout its limited range."
Stephen Sautner | EurekAlert!
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