Zebra mussels in a Nebraska Lake. Steven Schainost Nebraska Game and Parks 8 January 2009

Transcription

1 Zebra mussels in a Nebraska Lake Steven Schainost Nebraska Game and Parks 8 January 2009

2 So where are we? Bellevue and Offutt AFB at center right, just south of Omaha

3 Offutt Base Lake and environs

4 Timeline Date: 3 April 2006 Event: message from the Kansas ANS Coordinator Message: they had received a tip on their web site that someone had seen zebra mussels in the Offutt Air Force Base Lake

5 Timeline cont. I contact Offutt AFB via their public information system Phone call from Karl Morris which leads to setting up site visit Early site visit on 25 and 26 April 2006 where zebra mussels are confirmed and the situation is discussed with Base personnel

6 Offutt Base Lake - dead zebra mussels Dead shell under rocks Located on darkened waterline About 2 feet above 25 April 2006 waterline

7 Live zebra mussels on rock collected about 1foot below 25 April 2006 water surface Offutt Base Lake - lives up close

8 Offutt Base Lake - closeup of shells

9 Offutt Base Lake - discharge to river

10 Offutt Base Lake - lake side of discharge Bottom of discharge culverts are 3.5 above lake level on this date 26 April 2006

11 Offutt Base Lake - channel to river Discharge channel to Missouri River in background 26 April 2006

12 Offutt Base Lake USGS photo 19 April 1999

13 Offutt Base Lake Long view of boathouse and dock

14 Note darkened waterline. No zebra mussels were found above this line. Offutt Base Lake - south shore

15 Offutt Base Lake Actions to Control Situation Since only Base personnel may use lake, there is a higher level of control on use. Base personnel fishing lake must have a fishing permit issued on site. Boat docks were closed Brochures, etc., were made available in boathouse The outlet was plugged with concrete in the Spring of 2007

16 Offutt Base Lake Bathymetric map NGPC mapping crew constructed map in summer 2006

17 Offutt Base Lake Water Quality 12 June sites Calcium to 50.6 ppm Potassium to 8.8 ppm Conductivity to 414 us/cm ph to 8.47

18 Offutt Base Lake - First meeting 8 March 2007 Introductory meeting, statement of problem General presentation on zebra mussels Brian Watson, Virginia Coordinator of Millbrook Quarry eradication General discussion of problem and options

19 Millbrook Quarry, Virginia 12 acre, 93 feet deep Just west of Manassas, VA Privately owned and used for sport diving

20 Millbrook Quarry, Virginia Zebra mussel population discovered 2002 Flooding from adjacent creek or dive operations would have spread zebra mussels to other waters Decision made to attempt eradication

21 Millbrook Quarry, Virginia Eradication in Feb Potassium chloride (potash) Target concentration of 100 ppm

22 Millbrook Quarry, Virginia Cost was $365,000 Target concentration of 100 ppm well under EPA level of 250 ppm No impact on fishes or groundwater

23 Offutt Base Lake Meeting participants Offutt environmental and legal staff USFWS USACOE USEPA Iowa DNR Nebraska Game and Parks Nebraska Department of Environmental Quality Nebraska Department of Agriculture Public Power - Nebraska MidAmerican Energy - Iowa Kansas City Board of Public Utilities State Senator s office Local government

24 Offutt Base Lake - Second meeting 16 May 2007 Another general discussion of treatment options

25 Offutt Base Lake - Third meeting 3 October 2007 Another general discussion of treatment options Concluded that new options were being presented at each meeting which was slowing process Decided to cut off discussion at four treatments and develop spreadsheet with pros and cons of each Spectrus CT1300, Endothal, potash, copper sulfate

26 Offutt Base Lake - Fourth meeting 31 January 2008 Discussed spreadsheet with pros and cons of each of four options Deleted Spectrus CT1300 (Clamtrol) due to cost and concerns about efficacy Deleted Endothal because available information was that it will be banned by end of year Discussed pros and cons of remaining two treatment options: copper sulfate and potash

27 Potash Successfully used at Millbrook Quarry Maintains long-term toxicity Minimal impact on other species No impact on public use Great quantity needed (640 tons) Concerns about how to get into lake Cost has risen from $100/ton to $500+/ton (640 tons x $500 = $320,000)

28 Copper sulfate Crystals will sink to bottom and increase toxicity at surface of substrate where ZM live Less material needed (32,000 lbs) Lower cost = $63,360) Toxicity dissipates quickly Recommended to treat twice (spring and fall) EPA concerns about whole lake treatment

29 Offutt Base Lake - Fifth meeting 27 March 2008 Copper sulfate was selected DOD will have to pay all costs Need to move quickly to earmark available funds for this year Target date for treatment is before 1 May 2008 Possible second treatment in fall

30 Offutt Base Lake - Treatment Consultant (URS) hired to carry out project planning, obtain permits, write EIS, etc. subcontracted actual lake application to Natural Habitats Unlimited 17 September 2008

31 28,000 lbs. CuSO4

32 Shoreline done by pontoon boat

33 Mid-lake by boat with seeder

34 Treatment Day of treatment was perfect. No wind, no rain, full sun. Boats were guided by GPS Target was a whole-lake concentration of 1.0 ppm copper

35 Forklift loading pallet of bags

36 Lake levels were up from 2006

37 But were down from earlier in year

38 All solid substrates were infested

39 Fish kill began next day

40 URS personnel picked up all fish With a major airbase across road, Offutt required that all fish be picked up to avoid attracting fish-eating birds to eliminate possibility of bird-strikes on base

41 And buried them

42 Most surprising find was the Bighead carp

43 - Results - Copper concentrations in lake Date Location Range Mean 17 Sept Random 1.7 ppm (max) 0.70 ppm 19 Sept Seven sites Top/mid/bottom 17 Oct Same seven sites Top/mid/bottom 0.00 to 0.73 ppm 0.04 to 0.20 ppm 0.25 ppm 0.10 ppm

44 - Results - Zebra mussel mortality Six live colonies placed in minnow pails at six locations prior to treatment Examined at 24 and 72 hours and 7 days 24 hours - 30% dead 72 hours - 70% dead 7 days - 100% dead

45 - Results - Zebra mussel mortality Clean bricks and concrete blocks set out before treatment: No new settling found >100 rocks, etc. examined at 96 hours: No lives found

46 - Results - Veliger sampling Samples collected from three locations post-treatment 80 micron net w/ 20 cm opening 50 meter oblique tow from bottom to surface No veligers found [too late in year for veligers??]

47 - Results - Fish Kill: Sport fish, etc. Species Estimated weight (lb) Duration of kill Largemouth bass 10 3 to 7 Freshwater drum to 10 Crappie 3 Sporadic Paddlefish 100 Sporadic Walleye/saugeye 50 5 to 10 Catfish 5 15 to 20

48 - Results - Fish Kill: Nongame fishes Bighead carp 6,000 lb. 3 to 25 days Grass carp 200 lb. Sporadic Common carp 3,000 lb. 2 to 20 days Buffalo 28,000 lb. 2 to 40 days White perch 300 lb. 3 to 7 days Gizzard shad 200 lb. 1 to 3 days Gar, bullhead 15 lb. 15 to 20 days

49 Fish kill summary Estimated 39,000 lb. or 320 lb/acre of which 95+% were nongame fishes 72% buffalo 23% carp (bighead, common, grass) 0.4% sport fish

50 Cost? Actual cost figures are not available but the estimate was ~$100,000 or $820/surface acre Double that for the second treatment plus monitoring, etc.

51 Future plans A second treatment is tentatively scheduled for the first week of April, Veliger monitoring, 2009

52 A side note

53 A side note Caught at DeSoto Bend (Missouri River oxbow lake on Nebraska/Iowa border) 76 pounds