Invasive fish travels on land and in water

By Dick Nelson

There seems to be no end to the number of invasive species threatening state fisheries. The discovery of didymo aka “rock snot” in both the East and West Branch of the Delaware River as well as the Batten Kill in Washington County, is but one of many invasive species the state Department of Environmental Conservation (DEC) has to deal with, up to and including the Northern snakehead, which was discovered in both Ridgebury Lake and Catlin Creek in Waywayanda (Orange County) last May.

An aggressive predator fish, the Northern snakehead, which is as comfortable on land as it is in the water, has the potential to prey on and compete with native fishes throughout the state. In an effort to eradicate the species, and to protect clean water and restore a healthy and productive fishery and natural community, the DEC plans to treat both Ridgebury Lake and Catlin Creek with an aquatic pesticide in the coming weeks.

The agency realizes its actions will result in a temporary loss of fish populations, but according to DEC Regional Director Willie Janeway, it has already made a commitment to restocking and restoring the impacted waters.

“Specifically, DEC will selectively remove and hold some fish — other than Northern snakeheads — collected from Ridgebury Lake prior to treatment and return them shortly after treatment, when the water is safe for the fish. The reintroduction of these fish will help accelerate natural restoration processes,” Janeway said.

Ridgebury Lake and Catlin Creek are essential to protect native fish populations, natural communities and multiple clean water bodies including the Wallkill and Hudson Rivers.

Native to Asia, the Northern snakehead can disrupt an ecosystem and have devastating and unanticipated impacts. Snakeheads are predatory, consuming microscopic zooplankton and crustaceans as juveniles, and fish, insects and crustaceans as adults.

This, according to Janeway, can severely alter the feeding habits, food availability and behaviors of other members of an ecosystem.

Also, snakeheads can survive in water with very low oxygen, giving them a competitive advantage over other species, such as trout, pike and bass that require more oxygen in the water.

If you think you’ve caught a snakehead, the DEC recommends that you kill it, freeze it (double bag), and notify the agency at either 518-607-652-7366 in Region 4, or 845-256-3018 in Region 3, making note of the exact location of where it was caught.

This is important for determining the distribution of the species and the potential application of control and management strategies.

Invasive species have caused many problems in the past, are causing problems now, and pose threats to our future. A wide variety of species are problematic in many regions of the state, including aquatic plant species such as Brazilian waterweed, Curly-leaf pondweed, Eurasian water milfoil, European frog-bit, Fanwort, Starry stonewort, Water chestnut and Water primrose; Riparian plant species such as Japanese Knotweed and Giant hogweed; and Wetland plant species such as the Common reed, Flowering rush and Purple loosestrife.

But it is the aquatic animal species that cause the greatest harm to fisheries, and they include the Asiatic clam, Fishhook water flea, Northern snakehead, Quagga mussel, Round goby, Rusty crayfish, Spiny waterflea, Tench and Zebra mussels.