Getting Down in the Weeds:
Or Underwater Vegetation…If You Will
It’s easy for people to think of anything that grows under water as a weed. More appropriately, whatever grows down there is underwater vegetation. Most of the vegetation in DeRuyter Lake is native to the lake and contributes to the health of the lake and its fish population. Paul Lord helped many understand the lifespan of underwater vegetation by suggesting we imagine the bottom of the lake as lawns or gardens covered with water. Flowers, seeds, weeds, annuals, perennials, insects and everything else are there. Thinking of underwater vegetation that way, it is easier to appreciate the cycle of life occurring out of sight under the water before our eyes.
And with that bit of the big picture, it’s time to look at DeRuyter Lake’s underwater vegetation situation and introduce the initial effort of the foundation.
The first project of Tioughnioga Lake Preservation Foundation is the informally titled “fish project.” Succinctly, walleye pike fingerlings are stocked in the lake in large numbers. Those pike grow quickly by feeding on the lake’s plentiful population of small bluegills and sunnys. The blue gills and sunnys eat a “bug” that feeds on Eurasian milfoil. Ergo, more pike, fewer sunnys, more milfoil eating bugs and less milfoil. Simple premise.
Several important facts are part of the story. This is a natural process. No chemicals. The cost is in a five figure league for a few years, not six or seven! And best of all, it has a proven track record. The milfoil won’t disappear, but it will be controlled. That isn’t too much to ask.
The specifics of how the theory works - in scientific terms - are contained in the two stories below. Essentially, you can read about the implementation of a natural means to the Eurasian milfoil abatement program developed by Paul Lord. The articles originally appeared in Tioughnioga Lake Association newsletters in the Spring of 2012 and Spring of 2013, respectively. Both articles were written by Mike Curran who serves as the chair of the Environmental Committee of the lake association and is a member of the board of the foundation. Pictures and illustrations have been added to the original stories.
Mike Curran leading an information tour for the foundation board.
Paul Lord uses a lawn rakehead on a rope to haul in vegetation samples.
A Synopsis of UNDER THE SURFACE: Paul Lord’s 2011 Biomass Study of DeRuyter Lake by Mike Curran.
A more common name for this study is: The study of Eurasian water milfoil growth and herbivore insect impacts in DeRuyter Reservoir. Paul Lord presented a program of his initial study results to the TLA membership a couple of years ago. His work goes on. I’ve condensed over 80 pages of text, data, graphs and charts into this brief article from Lord’s 2011 draft. It hits some of the high points TLA members are most likely to be interested in. The entire final report will be available electronically from the Environmental Committee when it is completed.
The purpose of the study is to establish a baseline regarding milfoil presence and its density. Collections of plant specimens were made on five different dates, the last of which was in mid-December 2011. These collections were to ascertain the presence or absence of milfoil herbivores and the impact, if any, on the Eurasian milfoil. The focus of the research is the development of protocols for the biological control of Eurasian milfoil. Previous work on eight Madison County lakes has established a connection between size of the sunfish population and the number of an important milfoil insect herbivore, the aquatic moth. This connection has also been confirmed by studies in Minnesota. These macrophyte moth populations were associated with reduced Eurasian Milfoil density.
The research also included collections of standard lake physical and chemical data as well as electro fishing in late June to determine what impacts sunfish have on milfoil herbivores. Lord’s electro fishing data summarized two years of collection work from 2008 and 2011. There were 14 plant specimens identified in the 2011 sampling along with one macro algae.
Fish Count Survey
A species of a longhorn caddisfly was found that is not known and cannot be identified at this time. This DeRuyter caddis might be an exotic species. No North American caddis is currently associated with milfoil control. Two approaches are being pursued to determine its identification. DeRuyter Lake milfoil has not been a significant impediment to recreation in the last several years. This appears attributable to the caddisfly that was easily observable on the milfoil plants in June. This caddis was associated with significant damage to milfoil plants and kept the milfoil plants at a competitive disadvantage until late in the summer.
Two species of long horned caddis fly.
Milfoil bed development appears to be facilitated by sediment movement. Erosion is responsible for tons of sediment entering the lake and milfoil growth is profuse. The sediment plumes are associated with reservoir feeder streams in the south end of the lake. Storm water sediments bring in nutrients that encourage plant and algae growth.
Bad land use, lawns, unpaved roadways, wintertime salted paved roads and bare earth ditches surrounding our lake tend to abet sediment movement. These actions in turn raise concerns about salt, fertilizers and the use of ditching. Sidewalks, driveways, rooftops and even lawns facilitate the down slope of nutrients and pesticides into the lake. Salt use facilitates Eurasian water milfoil dominance.
Mechanical harvesting as well as chemical control have been used in many lakes around the county to try to control milfoil. Harvesting, if not done repeatedly over the course of a season, can result in denser growth. Because of the cost associated with this method of weed control, the TLA has opted to cut when the plants are at the peak of their seasonal growth - usually around the end of July. Unfortunately, insects living on the upper portion of the plants are killed. A little considered fact is that harvesting may kill four percent or more of the young fish in harvested areas.
Chemical applications as weed controls are very costly and their full, long- term environmental effects are not known. Cazenovia Lake suppression efforts worked well the first year of application, however, the decomposing biomass fertilizes new plant growth. Lake Moraine also uses a chemical application every few years. They have to reapply chemicals because the decaying plants fertilize new growth.
Milfoil weevils and midges were also studied in the collection of plant specimens. While insect herbivores are unlikely to eradicate milfoil in any body of water, they do have the potential to keep Eurasian milfoil from impeding recreation by keeping it from reaching the water surface. In some cases they help reduce the percentage of biomass in the plant community to single digits. While fish predation plays an important part in herbivore survivability, other forms of herbivore predation must be considered. Bats as well as predacious invertebrates, dragonflies, damselflies, hydras, water mites and flatworms are among possible limiting factors on herbivore counts.
larvae on stem
Paul Lord recommends stocking walleye fingerlings in addition to the fry currently stocked by the state every spring. That would ensure consistent suppression of insect eating fish (sun fish) and facilitate diversity of milfoil herbivores. The TLA will consider his recommendation and determine a possible course of action. Biomass harvesting will be done this summer according to word received from the Madison County Planning Department; extra harvesting may be required in the areas that are prone to heavy weed growth like the shallow south end of the lake and other areas Lord identified as problematic.
The estimated cost for the current general study is about $9,000 plus another $2,500 for electro fishing. Our share of the study costs were provided by Madison County. We expect the County will continue to fund additional study research through 2012. Expect to see Paul Lord at the lake this summer working on the next phases of the study.
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Finally: The Fish are Coming in June…all 50,000 of ‘em
By Mike Curran
The walleye fingerlings have been ordered - 50,000 of them and they will go into the lake in the middle of June. They will be raised by and delivered to the lake by Steve Sanford of the Sanford Fish Farm. Sanford will use a pond near Lincklaen, NY to raise the fish and he will certify their health before they go into the lake. After three years of study and research, we are underway.
Walleye fingering. Most 2" - 4" when placed in the lake in early August 2013. They should have grown several inches by late fall. The fingerlings were placed in the lake in a weedy shallow area on the peninsula near Shady Lane.
Three years ago Tioughnioga Lake Association (TLA) began to take part in and support a study to control Eurasian milfoil. The TLA worked cooperatively with the Madison County Planning Department, the major study support source. The purpose of the study, conducted by Professor Paul Lord from the SUNY Oneonta Biological Field Station, was to determine the best way to control the growth and spread of Eurasian milfoil. The study consisted of various surface and underwater aquatic macrophyte surveys as well as three night-electrofishing surveys and an in-depth review of twenty-four years of water chemistry data from the New York State CSLAP program. DeRuyter Lake data was compared and contrasted to the findings of earlier studies from other Madison County lakes.
At the 2012 Labor Day meeting of the lake association, the membership received a final report from Paul Lord titled, “2011 Eurasian Water Milfoil Growth and Milfoil Herbivore Insect Impacts in DeRuyter Reservoir.” One of the major conclusions of the report was that if walleye fingerlings (2” – 3”) were stocked along with the current walleye fry (pin head size) stocked by the DEC, there would be constant suppression of insect eating fish (mostly bluegills and sunfish) and, ergo, success in the effort to facilitate diversity and expansion of insect eating herbivores. Fingerlings have a much better survival rate than the walleye fry. The fry seem to become fish food. Electro fishing results concur with that conclusion. The walleye fish count in the lake is very low.
Last fall TLA President Richard Alter, a representative from Lebanon Reservoir (where the walleye fish stocking program was successful in the recent past) and I met with staff of the Dept. of Environmental Conservation in Cortland. We briefed them on the study findings and our plan. We told them that we believe this plan will increase the walleye survival rate and population and consequently have a significant impact by reducing the bluegill/sunfish population. These walleyes, as they grow will eat the small bluegill and sunfish and have a positive impact on the survival of a strong herbivore insect population. The herbivore insect population appears to biologically control milfoil. They eat the milfoil.
At the Sept. 2012 meeting of the TLA, the membership passed a resolution to support Paul Lord’s study recommendations and authorized the expenditure of up to $5000 per year of the three-year program with the proviso that other entities (Madison County (in for $5000 annually) and the Tioughnioga Lake Preservation Foundation) (in for $10,000 annually) agree to participate in the implementation of the study… recommendations at an estimated cost for just the fish of $20,000 per year. They did. That $60,000 minimum nut is out there.
The project has received commitments from the Madison County Planning Dept. to participate in the fish stocking program and its progress. There are funding commitments as well from the Town of DeRuyter, the Town of Cazenovia, the Town of Fabius and the Onondaga County. The newly established Tioughnioga Lake Preservation Foundation has committed to raising $13,500 a year for this project. The Foundation’s ability to fulfill its commitment to this project will depend in large part on generous, tax-deductible contributions from lake association members.
In the long view, after the three-year stocking, there will need to be continual monitoring of the progress. Additional stocking will depend upon the findings of new weed surveys and electro-fishing results. Future program costs will be contingent upon fish (walleye) survivability. The total annual cost of this program is estimated at $35,000 – where the fish stocking costs are picked up as described and additional expenses covered by these or other entities. This program is environmentally safe and is a prudent step toward control of the milfoil based on in-depth scientific study.
This natural method to control milfoil will be used in conjunction with our current weed harvesting program. Hopefully, the extent of weed harvesting needed will be reduced as the milfoil growth is under control. At the moment, weed harvesting is not enough to control an almost out of control aquatic weed vegetation problem and Paul Lord suggests improper or poorly timed weed harvesting may exacerbate the milfoil problem.
Thanks to the many contributors to the Tioughnioga Lake Preservation Foundation, this project will finally be underway. It is important that all of the TLA members support the ongoing efforts by the TLA and the foundation. Any and all donations are greatly appreciated, whether it be $25.00 or $50,000+. The best thing we can say to each other and the community at large is that we all are part of the team that supports our unique opportunity to get a hold on the problem of the invasive Eurasian milfoil.
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