more hydrilla found
Sharon K. Anderson
Good Afternoon,
This is an update from the Hydrilla Task Force of the Cayuga Lake Watershed, specifically regarding developments following the August 8th discovery of hydrilla growth in Fall Creek (Ithaca, NY), and the subsequent sampling the southern end of Cayuga Lake. We are working with an Ithaca Journal report, who intends to run an article in the next day or two. You can share this information. The attached file has a map and similar information in a question and answer format.
On August 21st, while conducting extensive surveys in the southern end of Cayuga Lake, survey crews from Racine-Johnson Aquatic Ecologists discovered three small patches of growing hydrilla in the south east corner of Cayuga Lake (See attachment). The first patch in the south east corner was found off shore from the Visitors Center in about 30 inches of water. This patch is comprised of two smaller patches, which are shown as one hot pink dot on the map since they are so close together (See attachment). Another patch further to the north was discovered during subsequent sampling, and was found growing in 40 inches of water. The largest of the three patches is approximately 12 feet by 45 feet.
In both 2011 and 2012, floating fragments of hydrilla were observed at the mouth of the Cayuga Inlet, meaning some fragments could have floated into the lake. A prevailing NW wind on Cayuga Lake pushes the surface waters back into the inlet, toward Stewart Park and into Fall Creek. It is possible that some fragments were blown into Fall Creek and others drifted past and settled in the south east corner of the lake. Sediment plumes after heavy rains frequently show the movement of water eastward along the shore of Stewart Park to that corner.
After surveying these patches, we believe that there are only one or two hydrilla plants in each patch that led to the observed growth. The Task Force’s plan is to very carefully remove all the plant mass above the sediment in each patch by hand. Fine mesh barriers will be installed to cordon off a patch. Divers, working inside the barriers and on the lake bottom, will surround the plant mass and carefully lift it with their hands. Any fragments that break off will be caught by the barriers and collected. Sandy bottoms in this portion of the lake, coupled with warm water temperatures, will allow the divers to work slowly and without gloves, minimizing sediment disturbance. After the plant mass is removed, the sediment will be sampled for tubers. These patches are small enough and the water shallow enough, that the Task Force believes hand removal has the best chance for successful eradication. Hand harvesting will be completed by September 6th (weather permitting). The Task Force will closely monitor the southeast corner of the lake for the effectiveness of the hand harvesting and to ensure there are no additional patches. As part of the existing eradication plan, ongoing plant monitoring in the lake will continue into December.
As previously mentioned in the notification email sent on August 20th, new hydrilla growth was discovered in Stewart Park Pond, Fall Creek, and adjacent backwater areas on August 8, 2013. It was following the initial discovery in these areas that survey crews from Racine-Johnson Aquatic Ecologists conducted extensive sampling within Fall Creek and the southern shelf of Cayuga Lake to determine the extent of the hydrilla infestation.
After several days of surveying Fall Creek and the southern end of Cayuga Lake, the Task Force now has a better understanding of the overall extent of the new hydrilla growth. As previously reported, hydrilla has been discovered growing in Stewart Park Pond (off of Fall Creek, NE side), the backwater area adjacent to Newman Municipal Golf Course (NW side of Fall Creek), and in scattered patches within Fall Creek (See attachment). Overall hydrilla growth in these areas is sparse, with a density much less than what was found in the Cayuga Inlet back in 2011.
Fences are being installed to keep boats out of the Stewart Park Pond, which has served as a kayak launching site, and out of the embayments along Fall Creek where hydrilla is established. We are working to get signs made to alert boaters and anglers to voluntarily keep out of Fall Creek until the area can be treated.
The Task Force is in the process of applying to the NYS Dept. of Environmental Conservation for a pesticide permit in order to prevent any further growth of tubers and plants in Fall Creek this fall. The herbicide Aquathol-K (active ingredient endothall), which has been used in Cayuga Inlet in 2011, 2012 and 2013, is the standard recommendation for a new infestation. The purple outline on the map shows the area for which we are requesting a permit (See attachment). The permit request is the maximum area where herbicide can be used. We plan to apply herbicides to a smaller area, not reaching out into the lake. The extra area provides some flexibility in case of unexpected hydrilla discoveries before the herbicide application.
As mentioned before, even though these newly discovered patches of hydrilla along the lake shore and in Fall Creek are a setback, we continue to believe that eradication is possible. We remain optimistic because we have caught these new populations very early, when growth is still sparse. This is exactly why ongoing plant monitoring/sampling is included in the eradication plan. As a direct result of our ongoing monitoring efforts and early detection, we now have an opportunity to address and eliminate this problem before it has a chance to spread. This also lends support and justification for monitoring and sampling for hydrilla and other invasive species on a broader scale. A statewide initiative of invasive species monitoring will greatly increase the rate of early detection, leading to greater rapid response if/when an invasive infestation is discovered. It is imperative that monitoring and sampling efforts for invasive species be conducted on wide-ranging scale, now more than ever.
Along with the immediate response outlined above, the Task Force is considering all possible responses for future treatments. We continue to consult with our state and national hydrilla experts who guide our present eradication efforts in the Cayuga Lake Watershed. Both the Task Force and our national advisors stress that we must push forward with all facets of the eradication plan – herbicide treatments, monitoring and sampling, and outreach.
Sharon K. Anderson
Environment Team Leader
Cornell Cooperative Extension of Tompkins County
615 Willow Ave., Ithaca, NY 14850
Cell 607-280-5580
Office 607-272-2292
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