Strangers in Lake Champlain
By Emmett Gartner
April 29, 2018
Lurking beneath Lake Champlain’s murky waters is a formidable predator with the capability of decimating entire populations of native fish. Victim to victim, the serpent-like beast wreaks havoc on the ecosystem and ashore, causing an estimated $29.4 million in economic damages to businesses and residents of the Lake Champlain basin. A description of a predator as daunting as this might easily lead to grandiose speculation. Could this be what has been summoned to bring about the alarming death of mudpuppies? Could it be Champ, the fabled Lake Champlain monster, killing prey to fulfill its mammoth diet? According to many area biologists, the answer to both of these questions is quite resounding… no. Considering that the prey of this effective predator is not swallowed whole, but left scarred and afloat, it is doubtful that their demise comes from a fall into Champ’s gullet, and, more notably, because Champ is merely fictional. Furthermore, their scars are not found on the dead mudpuppies that have recently been surfacing. Instead of finding the hitman, we have found the contractor: Petromyzon marinus, commonly known as the sea lamprey.
Natural selection is becoming increasingly artificial, calling into question the Darwinian principle. Often when one species of flora or fauna brings about the demise of another, there are ecological factors at play. The impact could be due to direct interactions, such as when predator kills prey. It could also be through indirect interactions, like competition over habitat or food that can cause losers to perish and victors to live to see another day. Either way, there is commonly a recognizable relation in the natural environment that brings about the decline of the predator or the prey. In Lake Champlain, we are witnessing a phenomenon that supersedes both of these conditions.
Die-offs of the common mudpuppy (Necturus maculosus), an aquatic species of salamander native to the Lake Champlain basin’s rivers and creeks, have been occurring at alarming rates in concentrated areas recently. These bottom dwellers are not the most charismatic of species the basin has to offer. They are only distinguishable from underwater debris by their unique ruby-colored external gills, small eyes, and four tiny feet, but what they lack in appearance they make up for in ecosystem services, acting as vital predators to aquatic invertebrates and small fish. Their overall population decline led to their designation as a “species of greatest conservation need” in Vermont and puts them at “high risk,” per the Vermont Natural Heritage Inventory, but did not earn them a spot on the state or federal Endangered Species Lists. In searching for the threat to mudpuppy populations, it is tempting to point to the notorious sea lamprey--and you would not be far off. However, in a Hitchcock-esque fashion, the lamprey conjures the outside help of mankind to bring about the die-offs.
Peaking at a length of approximately 24 inches, sea lamprey are speculated to be native to Lake Champlain, but thanks to increased food availability from modern fish stocking, their populations have skyrocketed. Adult sea lamprey penetrate the flesh of native fish species in a parasitic manner, latching on with their serrated, disk-like mouths and extracting bodily fluids, resulting in the hosts’ death 40 to 60 percent of the time. Their ability to kill over 40 pounds of fish in their lifetime has warranted the collaboration of the New York State Department of Environmental Conservation, the Vermont Department of Fish and Wildlife, and the United States Fish and Wildlife Service in implementing population control efforts, initiating a long-term program in 2002. The favored method of extermination? Chemicals. TFM (3-trifluoromethyl-4'-nitrophenol) and Bayluscide (2', 5-dichloro-4'-nitrosalicylanilide), to be exact. And at last, we have found the mudpuppies’ assassin.
Lampricides, as these two chemicals are known, are not limited to harming their namesake. By overrunning the basin and prompting human intervention, sea lamprey are inadvertently bringing about the death of species they have no relation to. Every four years (a time period that coincides with lamprey transformation from larva to predatorial adults) lampricides are utilized across New York and Vermont in concentrated sections of rivers to attack immature sea lamprey in their spawning grounds. Compilations of lamprey population statistics thereby allow biologists to propose a population control method for the lamprey-infested portions of rivers, with options ranging from physical methods like stream barriers and traps to chemical solutions, like TFM. Once these strategies have been proposed, permits are filed and approved or denied by regulatory agencies. Amongst these proposals are Environmental Assessments (EA) and Environmental Impact Statements (EIS) that determine the benefits and consequences of the proposed treatments, including the effects on non-target species. These scientific publications pay specific attention to the threatened and endangered species granted legal protection in Vermont, however, leaving a species of special concern like the mudpuppy unmentioned on most lamprey control expansion proposals that come out on this four year interval.
The EIS, titled “A Long Term Program of Sea Lamprey Control in Lake Champlain,” indicates a thorough study of mudpuppies in relation to lampricides, but lacks tangible concern. Other non-target species that have failed to receive state or federal protection also fade into the background of the program’s mission. Instead of intense regulation on lampricide use where these non-target species’ habitats overlap with sea lamprey that a protected species would receive, the equivalent of an honorable mention is offered under the “Unavoidable Adverse Impacts” section of the statement. This sections states: “Stream lampricide treatments may also cause generally minor levels of mortality to frog tadpoles, mudpuppies and salamanders,” ultimately favoring the lampricide option over more non-lethal and less effective physical methods.
Biological population assessments done in tandem with lampricide treatments reveal that these mortality levels can be far from minor. The most substantial TFM related die-off of mudpuppies occurred just under a decade ago in the Lamoile River, a quick thirty minute drive north of Burlington on I-89. During this 2009 treatment, a total of 512 mudpuppies perished alongside the targeted sea lamprey, intensifying scrutiny from members of the Vermont Endangered Species committee. In response to these alarming population impacts, biologists on the committee, including Vice Chairman Dr. Bill Barnard, vocalized concern in a 2012 report to the Vermont Agency of Natural Resources, asserting that “The time has come to put a halt to lampricide treatments until it can be shown that there is no effect on the listed species we are charged to protect.”
So where does this leave us? Coming this fall, the Champlain basin can expect to see two more names on the list of TFM treated tributaries, Little Chazy River and Red Brook, and once again, we can only sit back and observe which deaths of non-target species expand with it. Conservation organizations justify the widespread die-off of mudpuppies by pointing to the payoff of exterminating sea lampreys, but are putting the existence of non-target species, like mudpuppies, on the line. Instead of any concrete resolution, we are left with an ethical question: do we prioritize the lives of native mudpuppies, or death of overpopulated sea lamprey? At the very least, a louder voice of support could be raised for species that do not have tangible economic value to Vermonters. It is obvious that game fish have enough support on their own, or else this extensive program to exterminate sea lamprey would not exist in the first place, why not give equivalent support to an integral cog in the Lake Champlain ecosystem? Humanity has offered an extension of concern to non-target species before, as the start of the modern environmentalist movement coincided with efforts to save victims of another three letter chemical, DDT. While mudpuppies may not have the same allure as bald eagles and other birds susceptible to DDT, they are nevertheless deserving to the same right of life.
