Sturgeon showing its survival skills
Written by Baltimore Sun   
Wednesday, 25 May 2005 03:05
The sturgeon, a huge fish whose jagged armor makes it a likely inspiration for a legendary?Chesapeke Bay?monster, is appearing again in the bay and other waterways where it was once nearly extinct.

A 6 1/2 -foot-long, 115- pound Atlantic sturgeon was accidentally netted by commercial fishermen this month as they hunted for striped bass near the mouth of the Potomac River in Virginia's part of the bay. The fish is so powerful that, even in its tank, a single swipe of its tail rocked the pickup truck researchers used to drive it to the University of Maryland lab here in Dorchester County.

It is the largest of 60 sturgeon brought to the lab this year by bay fishermen seeking $100 cash rewards offered by researchers, who are keeping the fish in tanks for breeding. The number is up from the 34 sturgeon brought in last year and the three in 2003, said Andrew M. Lazur, an aquaculturist at UM's Center for Environmental Science.

"It's very exciting. You can't help but have your heart skip a few beats when you see these animals because they're just so unique - a Jurassic species that humans nearly wiped out more than a century ago," Lazur said. "Hopefully, we now have the capacity, as good stewards of the bay, to bring this animal back."

Although the numbers are still far too small to constitute a recovery of the species, the population of sturgeon being counted by scientists is rising not only in the Chesapeke Bay
, but also in New York's Hudson River, Lake Saint Clair in Canada, the Detroit River in Michigan and Minnesota's Lake of the Woods, according to researchers in those areas.

Slaughtered for their eggs during a craze for caviar during the late 1800s, some varieties of these passive, slow-moving, half-blind bottom feeders can live more than a century, grow to 27 feet and weigh 4,000 pounds. Dating from the time of the dinosaurs, sturgeon are an anachronistic fish lacking scales or teeth, instead having sandpaper-like hide, sharp plates along their back and blubbery lips that shoot like hoses into the mud to vacuum up mollusks, worms and other food.

"There is the beginning of a recovery going on, but it's still a small number of fish," said Bruce Manny, a biologist with the U.S. Geological Survey in Michigan. "In the 1970s, it was commonly thought that there were no sturgeon left in the Great Lakes. But they survived whatever killed the dinosaurs, and now it looks like they may survive all the insults we throw at them, too, with all of the industry and pollution."

Two possible causes for the resurgence are the Clean Water Act of 1970, which has gradually reduced sewage in some waterways, and bans on commercial sturgeon fishing, scientists said. Some varieties, such as the short-nosed sturgeon, are protected as endangered species.

The fish have also adapted themselves to what many consider an ecological catastrophe.

Zebra mussels, an invasive species, have been multiplying in many lakes and rivers across the country after being dumped into the Great Lakes in the 1980s by a cargo ship from the Caspian Sea. The mussels have caused billions of dollars in damage by clogging up industrial water intakes. But the invaders are a bountiful food source for sturgeon, which once thrived in the Caspian, said Boyd Kynard, a biologist who specializes in sturgeon at the U.S. Geological Survey lab in Turners Falls, Mass.

"We know the sturgeon are eating the zebra mussels," Kynard said, "and there is a direct correlation between when the zebra mussels got into the Hudson River, for example, and when the short-nosed sturgeon numbers in the Hudson started to grow."

The same is true in the Detroit River, where sturgeon are devouring zebra mussels and spawning in the least likely of places: amid the auto plants and sewage outfalls of Detroit, Manny said. "I think it's amazing that they've somehow survived despite the industrialization," Manny said. "Not long ago, the first young lake sturgeon seen in decades were found by fishermen in Lake Erie."

The Clean Water Act helped the return of sturgeon to the Mid-Atlantic region, but it is unclear if zebra mussels have played any role here, said David Secor, a fisheries scientist with the Chesapeake Biological Lab in Solomons.

After decades of absence, sturgeon are believed to be breeding in both the Delaware and James rivers, and occasionally swimming into the Chesapeke Bay
, Secor said.

"There is a lot of hope because of the breeding that we've seen in the James," Lazur said. "It's also extremely rare to find sturgeon this large in the Chesapeake."

For centures after the arrival of European settlers, the fish flourished in the Chesapeke Bay
and elsewhere in North America, Inga Saffron wrote in her 2002 book, Caviar. Colonists who arrived in the 1700s found sturgeon jamming streams each spring as they headed up river to spawn. The Delaware River was so packed with sturgeon that Philadelphia ferry passengers often saw the log-sized monsters leap high out of the water, sometimes crashing into the boats, Saffron wrote.

Tales surfaced in the Chesapeake region about a sea monster with a ridged back called Chessie, which some have speculated was a large sturgeon. Similar stores about hoary, ridged sea beasts arose with Loch Ness' Nessie, Lake Champlain's Champ, and Ogopogo in British Columbia's Lake Okanagan, all of which have been discussed as possible sturgeon.

Native Americans cherished sturgeon as a mainstay of their diet, spearing them from canoes. But European fishermen in the Chesapeake and elsewhere considered the fish a pest because its meat was considered too oily and its sharp ridges would tear up nets set for more desirable fish.

But the demand for sturgeon surged in the 1870s, driven by a European fad for nibbling their salty eggs, caviar. Sturgeon were easy to massacre because their clumsy, primitive bodies were easy to hook from shallow streams when they clustered during breeding.

Within 30 years, the fish were wiped out in most of North America. "They basically caught sturgeon until there weren't any more to catch, and they totally disappeared from the Chesapeake," said Steve Minkkinen, a researcher with the U.S. Fish and Wildlife Service.

By 1900, virtually all caviar production shifted to Russia, which is now decimating its sturgeon population in the Caspian Sea.

The University of Maryland lab at Horn Point is keeping 90 sturgeon caught in the?Chesapeke Bay
over the past three years in rows of large tanks.

Researchers hope to breed thousands of the fish, then release them with tiny radio transmitters embedded in their bodies so scientists can follow their progress as they try to recolonize, Lazur said. The project faces challenges because sturgeon require lots of oxygen - rare on the bay's polluted bottom - and are among the slowest-reproducing fish on earth. It sometimes takes 15 years before they reach puberty, and then they spawn only once every two to six years.

None of the females in the Horn Point lab is old enough to breed with the huge male caught May 13. That means researchers might have to wait up to five years until their oldest female matures.

The latest male to arrive seems impatient.

As scientists tried to wrestle him from the back of the pickup truck yesterday into the lab, he slapped his tail with a thunderous sound, and the pickup truck rocked. "Hopefully," Lazur said. "We'll soon get lucky and someone will find us a big female."

 
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