The mats remained in place over the winter and were removed last month during the second week of June. Prior to mat removal, the LGA contracted with DFWI to conduct surveys of the sediments that had built up on top of the mats as well as the sediment outside the perimeter of the matted area to see if there were any Asian clams present (indicating that they had escaped treatment). Sediment surveys were conducted in late May by DFWI. No live Asian clams were found during these surveys.
The LGA then contracted with AIM for mat removal at the site. Divers removed just over a half acre of benthic barriers from the Glenburnie Asian Clam site from June 9-12. Following the removal of the mats, an intensive survey using 2 mm sieves was completed by DFWI. A total of 487 sieve samples were taken and no live Asian clams were found in the survey.
Plans call for a follow up survey this September to confirm these results. Any small clams that might have been missed due to their size would have had a chance to grow to a size that would be found by that point.
These initial results are very promising! We have developed a good method for treating the clams. The problem is that they reproduce and spread so quickly, that we didn’t get them all treated in time at some of the larger sites that were first found in the Lake. So our initial treatment results were good, but they had escaped detection and it turns out they had already reproduced and spread. So we have had to take a step back and are unfortunately no longer in ‘rapid response’ mode. We are now trying to better understand how the clams are reproducing and moving in Lake George, so that we can be as strategic as possible with our limited resources. The Darrin Fresh Water Institute has a number or research questions that they are working on this year so that we can better understand how the clams are behaving in the lake. And we will continue with our lake-wide survey at the end of this summer to look for new sites.
|Staff from the LGA and the LGPC sampled for clams at multiple sites around the Lake on July 1.The metal square being used in this photo helps assess density of clams.|