Report on USFWS Contracted WRP Research Project

Assessment of the Potential for Zebra Mussel Invasion of Waters in the Western United States

via Saltatory Dispersal and Evolution of Increased Thermal Tolerance

Dr. Robert F. McMahonProfessor of Biology and Dean of the Honors College

John A. MorseGraduate Research Assistant

The University of Texas at ArlingtonBox 19222

Arlington, Texas 76019

11 September 2007 UT Arlington

Research Objectives

● Compare the acute and chronic upper thermal limits of zebra mussel populations from a warm southwestern habitat and cooler northeastern habitat

● Use data to assess development of physiologically resistant (thermally tolerant) races of zebra mussels in isolated southwestern populations

● Comparing genetic fingerprints (Amplified Fragment Length Polymorphisms or AFLP) of isolated zebra mussel populations and comparing them with samples from potential source populations

● Use data to examine how mussel dispersal patterns from one drainage system to another

Results

Chronic Thermal Tolerance

●Mussel samples collected from Lake Oologah, Oklahoma (2206, 2007), and Saratoga Lake (2006) and Hedges Lake (2007) in New York

●Acclimated in the laboratory for over two weeks to 5°, 10°, 15°, 20°, 25° and 30°C

●Subsamples held concurrently for up to 28 days at temperatures of 28°C, 29°, 30°, 31°, 32°, 33° and 34°C

● Samples checked daily for mortality ● Dead individuals removed

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25 °C 30 °CAcclimation Temperature

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Oklahoma New York

Mortality after 28 days at 29°C in zebra mussels acclimated to 25° and 30°C (2006)

28-Day Chronic Thermal Test Results 2007

Numbers above bars represents the time (in days) to achieve 100% mortality

14 16 6.5 26 4.5 19 3 5.5 2 1 1.5 0.5 0.5

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27°C 28°C 29°C 30°C 31°C 32°C 33°C 34°CTest Temp

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Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

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Oologah Lake Water Temperature

2006 2007

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Mortality after 28 days at 29°C in Lake Oologah zebra mussels acclimated to 20°, 25° and 30°C in 2006 and 2007

Lake Mead Quagga Mussel Research

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0 3 6 9 12 15 18 21 24 27 30012345

Las Vegas Boat Harbor, Lake Mead: 1/16/07

Callville May Marina, Lake Mead: 1/26/07

House Boat Pontoons

Lake Mead Marina, Lake Mead: 2/24/07

Cement Blocks and Cross Bars

Shallow Water (4 ft)

Katerine Landing, Lake Mohave: 3/13/0

House Boat Hulls

Callville Bay Marina, Lake Mead: 3/16/07

House Boat Pontoons

2006 Cohort

2006 Cohort

2006 Cohort

2006 Cohort

2006 Cohort

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2005 Cohort

Size Distributions of Quagga Mussels in Lake Mead

28 Day Mortality for Lake Mead Quagga Mussels Exposed to 20°C – 33°C

Numbers above bars represent the approximate number of days to reach 100% mortality.

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Temperature (°C)Starved Fed

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Lake Mead Temperature Profile at Sentinel Island

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Date1m 6m 12m 15m 20m 30m 50m 80m

Isolated Water Bodies SampledISOLATED WATERS

Water Body State Comments

Oologah Lake (after Aug. 2006) OK Obtained

Oologah Lake (before Aug. 2006) OK Obtained

El Dorado KS Obtained

White River AK Collection planned

Ossawinnamakee Lake MN Possible collection

Saratoga Lake NY Obtained

Hedges Lake NY Obtained

Ballston Lake NY Obtained

Base Lake NE Collection planned

Lake of the Ozarks MO Obtained

Diamond Lake MI Obtained

Detroit River MI Obtained

Wolf Lake IL Obtained

Mosquito Creek Reservoir OH Obtained

Milbrook Quarry VA Obtained

Lake Mead* NV Obtained

NON-ISOLATED WATERS

Water Body State Comments

Mohawk River NY Obtained

Lake Michigan** MI Obtained

Lake Erie** OH Obtained

Lake Ontario* NY Obtained

St. Lawrence River* NY Collection planned

Upper Mississippi Collection planned

Lower Mississippi LA Collection planned

Preliminary Conclusions

● Zebra mussels from Lake Oologah, Oklahoma are not more thermally tolerant than those from Saratoga or Hedges Lake in New York

● No evidence for selection of elevated thermal limits

● The incipient (long-term) upper thermal limit of zebra mussels Lake Mead qugga mussels appears to be ≈ 28°C regardless of latitude in North America

● The Lake Oologah, Oklahoma, zebra mussel population experienced near 100% extirpation during August 2006 and 2007 when water temperature rose above 28°C

● No evidence of selection for elevated thermal limits

● Lakes exceeding a surface temperature of 28°C for extended periods in the summer are unlikely to harbor zebra or quagga mussels

● Quagga mussels were first introduced to Lake Mead in 2003 or 2004

● Temperature profiles can be use to estimate the susceptibility of southwestern water bodies to zebra mussel invasion

● Lake Mead and the Lower Colorado River Lakes are susceptible to quagga and zebra mussel invasion

● Molecular analysis of the origins of isolated zebra mussel introductions will be completed by December 2006