The Lake George Asian Clam Rapid Response Task Force

The threat to Lake George and the Adirondack Park from the Asian clam (Corbicula fluminea) infestation discovered in Lake George in the fall of 2010 was quickly grasped by Lake George and Adirondack Park civic and regulatory communities. This group formalized into the ad hoc Lake George Asian Clam Rapid Response Task Force (LGACRRTF) to manage Asian clam in Lake George.

Wednesday, July 2, 2014

2014 Update at Glenburnie Site

Asian clams were found at Glenburnie in September 2013 during the lakewide survey. The site was determined to be still small, and was treated with benthic barrier in October 2013 (see the last post for treatment details) .

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.
 

Monday, November 25, 2013

Update on Fall Treatment Efforts for Asian Clams in Lake George


Working to install mats at Glenburnie site.
At the beginning of the month divers from AIM began fall treatment work at the Glenburnie site.  This new site was found during the lakewide survey on September 3. First the divers completed a thorough survey of the site to determine the extent of the infestation. They then installed benthic barriers weighted down with sand bags and rebar. Half of an acre was matted with 93 mats, held down with 2,500 pieces of rebar and 1,000 sandbags.  The plan is for the mats to stay in through the winter and to be removed in the spring prior to Memorial Day. 

 This is the only Asian Clam site being treated this fall.  Research is also underway to better understand the small, juvenile clams and how the clams are spreading around the lake. The Glenburnie site was surveyed by scientists at DFWI for juvenile clams prior to treatment, and none were found. So it is a good candidate for treatment.  The benthic barrier method developed by the Task Force over the past few years works well for killing adult clams, but clam infestations are still spreading.  One likely explanation is that small, juvenile clams (less than 2 mm in size) that have been released prior to matting efforts might be to blame for the continued infestations. So the Task Force has asked DFWI to help it better understand how the clams are behaving in the Lake.
Dave Wick, Executive Director of the LGPC updated the Warren County Board of Supervisor's Invasive Species Committee last Friday. Read an article about it in the Post Star here.    

 

Wednesday, September 11, 2013

Asian clams continue to spread despite successful matting results.

Spring post-treatment survey results suggested that the 7 acres of mats placed on the lake floor last winter successfully killed off populations of Asian clams in Lake George. However, a two-week lakewide survey currently in its second week reveals that the invasive clams are showing up in new locations as well as spreading beyond the treated areas.

New clam populations have been identified by volunteers and staff from the various organizations that make up the Lake George Asian Clam Task Force. New locations with clams have been found at Million Dollar Beach, Sandy Bay, Cotton Point and Basin Bay in southern Lake George, as well as the private boat launch area in Glenburnie in the Northern Basin.

“We have a sound and proven method to kill off the clams that we treat, but it’s not enough to contain them,” said Walt Lender, executive director of the Lake George Association.
Click here to read the entire press release.



Friday, September 6, 2013

Lake Champlain Maritime Museum Survey Work Video




The Lake Champlain Maritime Museum (LCMM) has been surveying known Asian clam sites to determine the current extent of the clams to inform planning for fall treatments.  This is a different type of survey work than the volunteer survey going on now that is looking for new sites.  The work the LCMM does is much more detailed - since we need to know exactly where the clams are so that we can smother them with benthic barriers.  Check out this great video that the LCMM made about their work.

Tuesday, September 3, 2013

Fall Asian Clam Survey has begun

Volunteers surveying for Asian clam. photo courtesy LGA

Efforts to survey the lake for new Asian clam locations began today.  Boats were out in both the north and south ends of the lake, with volunteers and staff from various organizations sieving the sediment to look for Asian clams on the lake bottom.

If you are still out on the lake with your boat, please be careful and keep an eye out for people wading near shore.  Survey work is scheduled for the next 2 weeks.

Friday, June 28, 2013

Spring Post Treatment Report Available

The 2013 Spring Post Treatment Report is available online. 
This survey assessed the success of the Fall 2012 Treatment, which was installed in the fall, left in the lake over the winter, and removed in the spring of 2013.
 

The report issued by the Darrin Freshwater Institute related to the control efforts for the invasive Asian clam in Lake George notes a success rate exceeding 98 percent in the treated areas. Asian clams were found in Lake George in late 2010, and control efforts were initiated immediately to eradicate this threat to the lake. Left unchecked, this invasive species multiplies rapidly, ultimately resulting in thousands of clams per square meter. Thanks to immediate action, no significant impacts from these clams have been noted in Lake George to date.

More than $1.5 million has been spent over the past three years to control this threat, and the results of the most recent fall/winter treatment are very encouraging. Seven of the 27 known acres of clam beds in Lake George were treated using plastic mats on the bottom of the lake, which smother the clams. There are a total of eight sites in Lake George with this invasive species, and two of the newly discovered sites were completely cleared of the clams, according to the report. In areas where the substrate is relatively flat and sandy, control efforts were 100 percent effective.

Thursday, May 2, 2013

Spring Mat Removal Work is Underway

Today is day 3 of removing Asian clam mats from the Lake. I'm sure the divers are liking this weather better than the weather last November when they were finishing up installing the mats!

Removal work started earlier this week on Tuesday, with the mats at Diamond Cove being removed, and then yesterday and today most of the mats from Boon Bay are now out as well. The divers are finishing up in Boon Bay either late today or tomorrow, and will then be headed down to Lake George Village next.
A crew has also been out on the lake ahead of the mat removal divers, to collect dissolved oxygen samples from ports in the mats.  Samples were collected yesterday and the rest are being collected today.
We are also preparing to start surveying the treated areas after the mats are removed, to assess the success of the treatment based on the live and dead clams found. Those results will inform future planning - so be sure to stay tuned!