Some of you met Greg Sass at Bass Pro with me. He is interviewed in this article.
Asian carp thriving in Illinois
July 18, 2008 at 02:03 PM
[/align]BY NICK VOGEL
[/align]HAVANA - There are more invasive Asian carp in the Illinois River this year than ever before, says Greg Sass, director of the Illinois River Biological Station in Havana.
"We estimate about 4,000 adults per river mile, with a (margin of error) range anywhere between three and six thousand. That"s just for silver carp. We estimate there could be about the same amount of large head carp," Sass said.
Scientists believe that Asian carp originated in Arkansas in the 1970s, where they were introduced into the ecology there to clean ponds, lakes and the bottoms of catfish farms. Sass said the carp may have swum upstream until they reached the Mississippi River. From there, the fish entered the Illinois River.
Sass said that employees working for the Illinois Natural History Survey capture silver carp, mark them, release them and then recapture them later. "The more re-captures we get throughout the summer, the closer (we get) to the true estimate of the number of fish that are out there," Sass said.
In other words, if the survey team captures a lot of their marked fish, they know that there is a smaller population. If they only capture a few of the marked fish, this means that the population has exploded, decreasing the odds of capturing a marked fish.
Results from the study show that there may be at least about 328,000 silver carp within an 80-mile stretch of the Illinois River.
And silver carp are only one type. Sass said the numbers may be about the same for bighead carp - another type of Asian carp.
The Illinois River provides the ideal conditions for silver carp spawning. They need long, unimpeded stretches of water. Once the fish spawn, the fertilized eggs flow down the river, then settle in slower moving backwater areas, where juveniles grow. As adults, they move out to the main part of the river.
"These fish are filter feeders so they feed on the very smallest plants," said Sass. And when it comes to small plants, the Illinois River is certainly productive.
Last year, the silver carp spawned three times in one summer. "This is very unusual. Most freshwater fish spawn only once a year," he said.
He compares their reproductive ecology to that of mice. "They"re always pregnant," Sass said.
As of yet, scientists have not been able to determine how long the Illinois River can sustain a growing population of the carp. "To this point we haven"t seen an end in sight," said Sass.
Their largest spawn event yet happened at the end of June. Sass said the mass numbers of baby silver carp are due to the sheer number of reproductive-ready adult fish and high flood waters that encourage spawning.
Right now, scientists are studying the biology of the silver carp to see if there is some way spawning can be controlled or decreased.
One species may help curb the carp"s numbers: Homo Sapiens. Sass said commercial fishing could have a huge affect on silver carp.
"They"re actually delicious. Three quarters of the world survive on these fish," said Sass. He said silver carp have a lot of bones, but if prepared properly, they can be a treat.
Sass said silver carp shouldn"t be confused with their unsavory relative, the common carp. Because silver carp are very low on the food chain - they eat very small plant life and algae - they have the least amount of heavy metals or contaminants in their body. The fact that silver carp grow quickly and have little fat also shows that they don"t retain dangerous levels of heavy metals, Sass said.
"This is a very good, healthy fish to eat," said Sass. When asked if he would rather eat a filet of catfish from the river or a filet of Asian carp, he said, "From a health perspective, it would probably be better to eat silver (carp) or bighead."
Comments ::
Guidelines ::
These carp are for sure going to ruin the ecosystem in our river and I hate to see that. I have grown up running around on the river. I have alot of great memories hunting ducks and fishing. The carp have sure put a damper on fun when it comes to water skiing, I have to end with this though. A person should not be able to have that much fun with a bow in your hand shooting those carp. It is a riot and sure has put some fun into my life. We are getting ready to start doing day trips in our pontoon boats, look in local archery shops for rates and contact numbers. It will be a day you won"t forget.
[/align]Posted by
shedhead on 07/19 at 10:28 PM
[/align][/align]
article on silver carp in the Illinois River
