Asian Carp Treatment update

[Spiel]

Asian Carp Treatment update

 

 

December 7, 2009 / www.great-lakes.org

 

 

After shutting the Chicago Sanitary and Ship Canal to all commercial and recreational traffic at 8 AM, biologists working with the Asian Carp Rapid Response Workgroup began applying Rotenone Wednesday evening, December 2, on a 5.7 mile stretch of the canal. This was after a small flotilla of electroshocking boats worked their way over that 5.7 mile stretch looking for desirable game fish. What they ultimately found was a small sampling of some largemouth bass, which were relocated to the Des Plaines River.

 

It was estimated that less than 3% of the fish that were shocked were game fish; the remaining were shad, common carp, and a few catfish and bullheads.

 

Officials then launched what’s believed to be the largest deliberate fish kill in state history Wednesday night. Crews had earlier dumped 2,200 gallons of the toxin rotenone into the canal. Dozens of boats combed the Chicago Sanitary and Ship Canal starting in the pre-dawn hours on December 3, ultimately finding a lone Asian carp among tens of thousands of poisoned fish, about 50,000 lbs of dead or dying carcasses.

 

The one Bighead Asian carp was discovered nearly 500' above the Lockport Lock on Thursday afternoon, December 3. Biologists with the workgroup believe there is a high probability that additional Asian carp were killed during the toxicant application but may not be found. It is generally believed Asian Carp respond differently to Rotenone than other fish, dying land sinking to the bottom. If they do surface – in spite of the increasingly colder water, it won’t be till they get bloated and fill with gas.

 

An important question biologists will try to answer is how large a population of Asian carp exists above and below the electric barriers. Researchers collected fish DNA indicating that the invasive carp are present in the canal and have advanced beyond the barriers, but there have been no actual sightings of the carp in those locations.

 

Illinois DNR spokesman Chris McCloud said some of the data collected last week will help biologists figure out the reliability of those DNA samples. "We have to know where they are and how many there are," he said.

 

“The cold water temperatures on the canal this week means far more fish are sinking to the bottom of the waterway than will float to the top. Over the next several weeks and months, some fish may float to the surface but the majority of fish will break down naturally below the surface,” said Illinois DNR Fish Chief Steve Pallo.

 

The workgroup had collected thousands of fish, mostly common carp, from the canal since cleanup efforts began on December 3.

 

The workgroup is now focused on efforts above the electrical barrier system near the O’Brien Lock in an attempt to find Asian carp in areas where positive eDNA tests have been found. Positive Asian carp DNA evidence exists over nearly 10 miles of the Cal-Sag Channel and Sanitary and Ship Canal above the barrier.

 

Maintenance on the electric barrier, IIA, was completed and the barrier was returned to operation at 10 p.m. on Friday, Dec. 4.

 

The workgroup has been using commercial fishermen, augmented with state and federal fisheries personnel, to deploy commercial fishing gear in a 5.5-mile stretch of the Cal-Sag Channel. Fishing operations used nearly 2,000 yards of fishing nets deployed for two overnight periods. Nets were deployed over portions of the reach since Dec. 1 and have been highly successful in collecting fish, although no Asian carp have been collected.

 

Spokesmen for the workgroup say while the workgroup considered additional Rotenone application in specific areas above the barrier as a sampling option, there is no evidence to suggest Asian carp might be concentrated in any specific part of the 10-mile stretch of the canal where eDNA tests have been positive.

 

Fishing nets would effectively sample the entire reach and provide the best evidence of the potential presence and abundance of Asian carp in this stretch of channel. It would also confirm the exact location of any fish collected. Any Asian carp collected will be removed from the system, providing a measure of population reduction.

 

“The effort near the O’Brien Lock is fundamentally different from the action below the barrier. The purpose of applying Rotenone below the barrier was to ensure no Asian carp advanced up the channel while the barrier was powered down for scheduled maintenance. In addition, Rotenone would provide little if any information about the presence and abundance of carp in this reach upstream,” said IDNR Assistant Director John Rogner.

 

Rogner added; "We are also looking at bubble curtains, a constant wall of live bubbles we've tested on some fish that repels them. We are also experimenting with steady streams of noise that bothers fish." "We also are studying methods that have been successful in controlling sea lamprey in the Great Lakes, such as capturing and sterilizing fish so they can’t reproduce" he said.

 

The U.S. Army Corps of Engineers meanwhile, is reviewing all available data and may make a decision soon on closing down one or more of the Locks near Lake Michigan, to prevent potential or additional migration of Asian Carp into the lake. Many issues are being weighed including the impact to commercial barges and the movement of commodities such as raw building materials, coal and petroleum into the area. That decision could be made any day.

 

The Asian Carp Rapid Response Workgroup includes the Illinois DNR, U.S. Army Corps of Engineers, USEPA, USFWS, US Coast Guard, USDA, and Wisconsin Sea Grant. Many other agencies supplied support and expertise. Fisheries management agencies from all eight Great Lakes States, Ontario and Dept of Fisheries and Oceans Canada provided manpower and support to the operation. More than 350 people contributed to the efforts on the ground during the week’s operation

 

 

Potential Distribution – Silver Carp

 

 

 

Potential Distribution – Bighead Carp

 

 

 

These maps were peer reviewed and published in the primary literature (Canadian Journal of Fisheries and Aquatic Sciences) and use more rigorous scientific methods than those produced in the 2005 Canadian risk assessment. Using the two (2005 risk assessment and these maps from the 2007 paper) provide a good view of the assessment of biological risk of Asian carps. According to DFO, all Canada Rivers are at risk. Dept of Fisheries and Oceans Canada, 2007