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.

Tuesday, November 3, 2015

2015 Lakewide Survey Results

Year 2015 marked the fourth year of the lake‐wide survey to identify any new locations of invasive Asian clams (Corbicula fluminea) in Lake George. There were 45 people who signed up to participate in the survey August 26th through September 1. Participants ranged from agency and nonprofit staff to private individuals with an interest in the lake. The survey work includes sieving (like panning for gold) through all sandy areas throughout the shoreline of Lake George to find any new populations of this invasive mollusk.

This year’s survey identified two new locations of Asian clams in Lake George, and slight expansion of several existing sites. The following are the key findings of this year’s survey:

1. New Site #1: Rogers Rock DEC Campground Beach (Hague) – Discovered a small area of Asian clams on the eastern side of the beach, approximately 30’ diameter, in which 4‐8 juvenile clams were found in every sieve. No clams were found outside of that one small area. This is the northernmost site currently known in Lake George, and is in a highly utilized area.

2. New Site #2: Basin Bay Association, North side of Basin Bay (Bolton) – Clams discovered along length of beach of the Association, zero to four clams per sieve along most of the beach, mostly juvenile size class.

3. Blue Lagoon Resort Beach (Diamond Point) – Clams were discovered at this beach, which is a northward expansion of the Diamond Cove Cottages Asian clam site.

4. Veteran’s Park Beach (Bolton Landing) – Dozens of dead Asian clam shells discovered at the beach north of the wooden dock on the south of the property, at the outer edge of the swimming area. This is likely an expansion of the Norowal Marina site, although no live or dead clams have been discovered here until this year’s survey. Will monitor closely.

5. LG Steamboat Company (Lake George) – Dead Asian clams discovered under the steamboat berthing site at the Steamboat Company, discovered by Darrin Freshwater Institute independent of this study. The site lies between the known sites of Million Dollar Beach and Shepherd Park Beach, but is some distance from either.

6. All 14 previously known sites were confirmed to still have populations of Asian clams in varying degrees of density (a few clams per square meter up to more than one thousand clams per square meter). Further study this fall will identify relative densities of the known sites.

The full 2015 Asian clam Lakewide Survey Final report can be seen here.

Monday, March 23, 2015

Asian Clam Transport Study Completed

The Darrin Fresh Water Institute just completed a study designed to help the task force better understand the in-Lake transport of Asian clams. The project focused on various modes of transport, including: Via boat anchor and propwash, through natural means, and via plant material.

It found that anchor sediments are a potential way Asian clams to be transported; that propwash wasn't a primary mechanism. it found that juveniles can be transported at least 50 feet from known beds, that the water column is a vector for transport, and that plant material isn't the primary transport vector.

You can read the whole report here: Final Asian Clam On the RuN (ACORN) report

Monday, October 6, 2014

2014 Lakewide Survey Results

4 boats and 55 individuals volunteered in early September to survey shallow, sandy locations around the Lake for Asian clam. No new significant locations were found, although one new small location was found and a number of existing sites expanded in size.
Summary of findings:
  1. Candlelight Cottages (Jacobie Pt): One Asian clam approximately 6mm in diameter was discovered at the beach at Candlelight Cottages in Northwest Bay in the Town of Bolton. Upon finding, hundreds of additional sieves were taken, yielding no new clams. This is approximately one mile north of the closest known site of Asian clams at Norowal Marina.
  2. Glenburnie: One clam approximately 6mm in diameter was discovered at the launch site in Glenburnie in the Town of Putnam. This is the site of the 2013‐2014 eradication project, where more than ½ acre of mats were installed to eliminate this population. More than 800 sieves combined overtwo separate days were taken to identify any additional clams, but none were found.
  3. Million Dollar Beach: The west side of MDB in the Town of Lake George was identified as an Asian clam site in 2013, but no treatments were undertaken there. Clams were now identified in moderate abundance on the eastern portion of the beach, extending onto the East Brook delta. Sizes range from 3mm up to 8mm in diameter.
  4. Blue Lagoon Resort: One Asian clam was found at this resort, which is two properties north of the closest known Asian clam site at Diamond Cove Cottages approximately 100 yards to the south.
  5. Waters Edge Marina: One shell from a dead Asian clam was identified at this Marina in the Town of Bolton, which is adjacent to the Green Island Bridge. This is approximately ¼ mile south of the closest known location at Norowal Marina.
  6. Existing Known Sites: While this survey was not intended to assess the existing known locations of Asian clams, several of these sites were surveyed through this project to get a general sense of current population density. In general, it has been noted that the populations of Asian clams are significantly reduced from the 2013 densities, anecdotally noted as much as 90% reduction in some areas. This has been linked to the severe previous winter that Lake George experienced. This winter die‐off was validated through research that McGill University in Montreal has been conducting over the past few years. Their researchers note that more than 60 days of extreme cold water (36 degrees or less) results in mass die‐off. Lake George was noted as meeting those conditions in the 2013‐2014 winter.

Click here for the full report

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.