140 likes | 522 Views
Quagga Mussels. Western Invasion Update. David K. Britton, Ph.D. Southwest Regional Assistant AIS Coordinator Fisheries & Aquatic Resource Conservation . Photo Credit: Wen Baldwin, Lake Mead NRA Volunteer. Outline. Invasion Update National Parks Response Plan New Infestations
E N D
Quagga Mussels Western Invasion Update David K. Britton, Ph.D.Southwest Regional Assistant AIS CoordinatorFisheries & Aquatic Resource Conservation Photo Credit: Wen Baldwin, Lake Mead NRA Volunteer
Outline • Invasion Update • National Parks Response Plan • New Infestations • Status of Lake Powell • Veliger Monitoring • At-Risk Locations
Lake Mead NRA • Adult mussels covering boat hulls in Boulder Basin • Veliger larvae densities dramatically increased
Quagga Mussels Veliger Density Lake Mead National Recreation Area, 2007 Source: U.S. Department of the Interior – Bureau of Reclamation
NPS Quagga Response Plan • http://www.nature.nps.gov/biology/Quagga 1. Introduction 2. Partnerships and Communications 3. Situation Analysis and Resulting Actions 4. Preventing Q/Z Mussel Infestations 5. Monitoring and Detecting Infestations 6. Response to a Mussel Infestation 7. Safety Considerations 8. Financial Considerations
Glen Canyon NRA • Modified Portland Artificial Substrate Samplers • 9 to 15 Portland Samplers have been maintained in Lake Powell at Marina and other access areas since 2002. • Samplers were modified to reach deeper depths (about 40ft or 15m) in 2007. • To date, no signs of mussels have been found on the samplers. • Plankton Sampling for Veliger Detection – • Over 50 Lake Powell-relevant plankton tows have been collected for veliger analysis since June 2007: • Many of these samples have not yet been processed, but indications of mussel veligers have been found in some samples. Results are summarized in the tables below. • Dive Surveys • Diver Boat Inspections - Over 500 boats in the Wahweap Marina have been inspected • No mussels have been found during boat inspections. • Deep Dives - About ten deep dives following marina cables to concrete weights have been conducted to about 40m (130ft) under the Wahweap Marina. • No mussels have been found in deep dives. • Submarine Remotely Operated Vehicle (ROV) Surveys • Five sites in the submerged canyon below Wahweap Marina have been searched by ROV at depths up to about 70m (240ft). • No mussels have been found.
Parker Dam, Lake Havasu Test Plates were cleaned on 6/28/08. This picture taken on 8/6/08 • Glen Tuerschmann, Parker Dam Facility Manager • Mussels are beginning to establish themselves in the dam facilities
Havasu Springs Larry [Riley], Two observations: BOR recently assisted us in restoration of the public fishing dock at Havasu Springs. Quagga mussels were recovered and reported (eyeball estimation) to cover the bottom of the dock at densities approaching 6 per square inch. Today, I pulled the 2 inch pipe sampler. The sampler was placed at the boat dock at Partner's Point at a measured depth of 10 feet. Seechi disc transparency at this location is the bottom, i.e. 18 feet. The sampler was in the water for a total of 45 days. There were 213 mussels attached varying in size from just visible to 12 mm. Only 4 mussels were located on the outside of the sample. The inside walls held 97 while the lace material contained the rest. In several places they were actually clumped several mussels deep with varying sizes. Doug Adams Fisheries Biologist BLM - Lake Havasu City Field Office
Early Detection: PCR Analysis • Determines presence or absence of zebra/quagga mussel larvae • The current techniques used are over ten years old • Process is not cutting-edge • Requires more technical time than necessary • Costs are an order of magnitude too high • Improvements Can be Made • BOR needs $60,000 for research to develop improvements which will decrease costs (to $20 - $30) and increase accuracy of each PCR analysis • Once developed these techniques and processes would be available for use by any microbiology lab • Estimated time necessary for improvements is 6 months. • “This could be another big step ahead in our efforts to monitor and detect presence of zebra/quagga mussels when incipient populations may be vulnerable to eradication efforts.”– Bob Pitman • This would truly give us “early detection and rapid response” capacity