WEST LAFAYETTE, Ind. - They take a long time before they mate and, once old enough, don't mate every year. Even so, sturgeons are heavily sought after for their eggs, which are made into caviar.
For these and other reasons, many sturgeons - a variety of ancient, bottom-feeding fish - are in trouble.
Trent Sutton, a fisheries biologist at Purdue University, has helped to ensure that a local variety of sturgeon, the shovelnose, does not become endangered or threatened like many of its relatives.
"The problem with sturgeons in general is that they are a long-lived fish that take a long time to reach sexual maturity," Sutton said.
He has completed a series of studies on the shovelnose sturgeon in Indiana waterways, particularly the Wabash River. His findings have become the basis for size and catch limits on the fish that will be put into place next summer, said Bill James, chief of fisheries for the Indiana Department of Natural Resources (DNR). There are currently no fishing regulations for the shovelnose.
Sutton's research identifies many of the fish's habits that were previously unknown. Importantly, he found that the Wabash River population appears to be stable. Nevertheless, his sampling uncovered very few young fish in the river.
"This raises a few red flags," Sutton said. "This means that either the females aren't laying eggs or that they aren't spawning at all - both of which would have serious ramifications."
Another possibility, he said, is that the researchers' sampling may not have been in the right place and most of the young were somewhere else.
"This is an issue that needs to be resolved," he said.
The shovelnose, the smallest of sturgeons, reaches sexual maturity between ages 6 and 9 and spawns about every other year. This is relatively quick growth compared to the lake sturgeon, now endangered in much of North America, that doesn't reach sexual maturity until 2
Contact: Douglas M. Main