Barbs and Backlashes


Some updates by Nebraska Game and Parks Commission
November 13, 2009, 5:52 pm
Filed under: Fishing | Tags:

It has been a busy day.  I wanted to get a blog post up before the weekend.  This one will include a couple of different topics.

Zebra Mussels

Many of you know about the zebra mussel infestation of the Base Lake at Offutt Air Force Base in Bellevue.  Many of you are also aware that efforts were made to eradicate that population of zebra mussels.  There has been a final report produced detailing that successful eradication effort.  That report is not available on-line, so I am going to copy and paste a couple of sections of interest here.  This is taken from the Final Summary Report Zebra Mussel Eradication Project, Lake Offutt Offutt Air Force Base, Nebraska.  I believe the report was prepared by the URS Group, which I believe was the consulting firm that performed the eradication.  This report was just completed, November 2009.  Anyway here is the executive summary from that report:

EXECUTIVE SUMMARY
Zebra mussels are an invasive species from Eurasia that were introduced in Lake St. Clair, in the Great Lakes region in 1988. The ability of zebra mussels to attach to hard surfaces, their ability to live for extended periods out of water, and the small size of their larvae (veligers) allow them to be transported unknowingly on recreational boats, trailers, and bait buckets, and has contributed to their rapid range expansion. Within four years after being introduced in Lake St. Clair, zebra mussels had become established in all of the Great Lakes as well as the Arkansas, Cumberland, Hudson, Illinois, Mississippi, Ohio, and Tennessee River systems.

It is believed that zebra mussels gained access to Lake Offutt when a boat or boat trailer that had been used on a water body infested with zebra mussels was transported and unloaded into Lake Offutt. The Nebraska Game and Parks Commission (NGPC) confirmed the presence of zebra mussels in Lake Offutt in April 2006. This was the first confirmed reproducing population of zebra mussels in the state of Nebraska. The Zebra Mussel Working Group was formed to discuss  treatment options and preventative measures and included representatives from government agencies and private stakeholders. Offutt Air Force Base (AFB), in cooperation with the Zebra Mussel Working Group, determined that treating the lake with copper sulfate would be the most feasible treatment method with the greatest potential for successful eradication.

Offutt AFB contracted URS Group, Inc. (URS) to treat Lake Offutt in an attempt to eradicate zebra mussels (Dreissena polymorpha). An United States Environmental Protection Agency (USEPA) Special Local Need Label was acquired in order to treat the lake with a sufficient concentration of copper sulfate to eradicate zebra mussels (1 part per million [ppm] lake-wide copper concentration). Copper Sulfate was applied in two treatments to Lake Offutt over 30- hour periods on 17 and 18 September 2008 and again on 7 and 8 April 2009. Post application monitoring was performed in four categories: 1) water quality, 2) adult zebra mussels sampling, 3) larval zebra mussels sampling, and 4) fish mortality. Thus far no zebra mussels have been detected in Lake Offutt since the first treatment was applied.

And here is another section that will be of particular interest to anglers.

3.4 FISH MORTALITY RESULTS

Copper sulfate was applied to Lake Offutt at a concentration of 1 ppm elemental copper.  Although copper sulfate is an approved chemical that can be applied in the aquatic environment for the control of aquatic weeds and snails, many previous applications were either at lower application rates or were used as spot treatment for control of nuisance aquatic weeds. Some fish mortality was expected since copper is known to be toxic to certain fish at lower concentrations under various conditions. However, it was not known which species would be affected or to what extent due to differing sensitivity or exposures to the chemical.

Fish mortality occurred following both the 2008 and 2009 copper sulfate treatments, and extended over a prolonged period in both events. Table 3-5 lists the 21 fish species killed following the copper sulfate treatments. Table 3-6 provides the estimated weight of dead fish collected as well as the time period of mortality. As stated previously, the Special Local Need Label issued by the USEPA required that all dead fish be picked up and disposed until no dead fish were found during a 48-hour period. Dead fish were picked up for approximately 5 weeks following both the 2008 and 2009 treatments and buried in an area adjacent to the lake. Both the species composition and the poundage of fished killed varied between the two treatments.

In 2008, dead fish were evident starting on 18 September 2008 (during the second day of the copper sulfate application). Dead fish removal started immediately following the completion of the application of the copper sulfate and continued for approximately 5 weeks. During this period, approximately 38,500 pounds of dead fish were collected (Table 3-6). This quantity of fish killed equates to approximately 320 pounds of fish per acre. The vast majority (approximately 72 percent by weight) of dead fish recovered in 2008 were buffalo (bigmouth and smallmouth). Other species that were killed in sizable numbers included common carp, grass carp, bighead carp, white perch, freshwater drum, and gizzard shad. Smaller quantities of game fish species (largemouth bass, smallmouth bass, paddlefish, black bullhead, flathead catfish, channel catfish, crappie, and walleye/saugeye) were also killed in 2008. As will be discussed in the following paragraphs, approximately 97 percent of the fish killed (by weight) were non-game fish and less than 0.2 percent was prized game fish (bass, catfish, walleye/saugeye, and crappie).

In 2009, distressed fish were observed on 8 April 2009, during the second day of the copper sulfate application. Collection of dead fish started on 9 April 2009 and continued until 15 May 2009. Approximately 3,000 pounds of dead fish were collected and buried. The 2009 treatment resulted in an approximately 26 pounds per acre of fish being killed of which almost 86 percent were non-game species. The majority of the fish collected were buffalo (bigmouth and smallmouth) and common carp. Other species that were collected in fairly significant numbers were freshwater drum, bighead carp, and crappie. The majority of crappie that was collected died within the first two weeks after treatment. In 2009 prized game fish (largemouth bass, smallmouth bass, channel catfish, flathead catfish walleye/saugeye, and crappie) comprised approximately 10 percent of the poundage killed.

In summary, it was apparent that some species of fish were much more susceptible to copper sulfate than other species and the period of mortality is shown on Table 3-5. Based on the fish collected, the most susceptible species included gizzard shad, common carp, bigmouth buffalo, smallmouth buffalo, bighead carp, walleye/saugeye, and freshwater drum. In 2009, an estimated 3,000 pounds of fish were killed and, similar to the 2008 event, the majority of species affected were the non-game species (mostly buffalo and common carp). However, the overall mortality rate was drastically lower in 2009. The biomass killed following the 2008 treatment (approximately 320 pounds of fish per acre) may have had major influence on the quantity of fish remaining in the lake in 2009. Another disparity between the years is that a larger number of crappie were killed in 2009 (approximately 600 individuals). Only one new species (bluegill) was collected in 2009. Two species (paddlefish and black bullhead), were collected in 2008, but not in 2009. In 2009 there were fewer gizzard shad, white perch, walleye/saugeye, and freshwater drum. In 2009 the precise periods of mortality by species was not as pronounced as it was in 2008. In summary, the two copper sulfate treatments resulted in approximately 1,500 pounds of dead fish being removed from the lake, of which over 40,000 pounds (97 %) werenon-game and invasive fish species and approximately 325 pounds (less than 1 %) were prizedgame fish species.

There is more in that report, and I wish I could just post a link to the whole thing, but those are the high points, those most interesting for anglers.  For more information on invasive species in Nebraska, please check out this website, http://snr.unl.edu/invasives/index.htm !

Lawrence Youngsman

Lawrence Youngsman is the name that has been given to the new reservoir on West Dodge in Omaha.  I know lots of folks are wondering about the status of this fishery and when the gates will be open.  The City of Omaha has had the area closed to finish developing the area and they initially intended to complete that work by this fall.  The latest update I have heard is that they still have some work to do and have had some erosion problems that they are still addressing.  The target date for an official opening is now next spring.

That is boring, no stories of big fish, but I thought those would be of interest.  Have a good weekend and every chance you get GO FISH!

WTMuskie34_06Head

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[…] Daryl's Barbs and Backlashes: Some updates It has been a busy day.* I wanted to get a blog post up before the weekend.* This one will include a couple of different topics. Zebra Mussels Many of you know about the zebra mussel infestation of the Base Lake at Offutt Air Force Base in Bellevue.* Many of you are also aware that efforts were […] More… […]

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