Controlling Snakes around Stormwater Ponds
In South Carolina, encounters with snakes are common and the vast majority of them go without incident. Of the 42 species of snakes that live in South Carolina, only 6 are venomous, and only two of these consistently live near water, the copperhead and the cottonmouth (a.k.a. moccasin). Several non-venomous species live near water, and to the untrained eye they resemble their venomous relatives. Both the venomous and non-venomous "aquatic" snakes are using the same food resources: fish, bird nests, ducklings, frogs, small mammals and insects. Combine food, water, and cover, and the habitat may be suitable for water-loving snakes.
How can venomous snakes be distinguished from the non-venomous snakes?
Both species of "aquatic" venomous snakes are pit vipers, meaning that they have small pits in front of their eyes. They also have stocky bodies, triangular heads, and elongated pupils like cat eyes. Their non-venomous relatives are longer and leaner, have rounded heads, no pits, and round pupils like human eyes. It is not advised that inexperienced residents get close enough to snakes to determine presence of these characteristics.
Do snakes cause management problems for stormwater ponds?
Other than frightening residents, snakes do not negatively affect how the pond functions or the ecology of the aquatic ecosystem. In fact, snakes help manage the pond by keeping frog, duck and insect populations in check. They also indicate that your pond is biologically productive and is producing the resources the snake needs to survive, a signal that the pond is not impaired by pollutants and other ecological problems.
How can I control snakes around my pond?
Snakes have a place in the environment and should be avoided rather than removed. On the other hand, if a particular snake is occupying a space to be used by a resident (porch, lawn, dock, etc.), then the resident may choose to have the animal removed. Unless the homeowner is familiar with snakes and can determine venomous from non-venomous species, then the waterfront owner should contact a licensed nuisance wildlife control operator (click here for a list) to have the animal trapped and removed by a trained professional.
Are there any deterrents to repel snakes?
Yes. Several repellents are labeled to deter snakes, but these products produce inconsistent results. Several environmental factors (temperature, time of day, duration since last application, humidity/precipitation) affect the effectiveness of these compounds. Moth balls (naphthalene) are not a recommended snake deterrent. Liquid repellents may provide limited control but must be reapplied regularly, making them cost prohibitive.
Should I remove shoreline plants to reduce cover for snakes and their prey?
Reducing cover will reduce the likelihood of a snake encounter, but it may result in more significant and costly problems than the snake. Shoreline plants should be protected right at the water's edge in order to prevent erosion and limit pollution in the pond. Above the immediate shoreline on the bank slope, homeowners may choose to reduce cover by mowing regularly, but plants at the water's edge should be protected. Trees and shrubs should be minimized on the bank slope. (See section on Shoreline Plants.)
For more detailed information on the biology and identification of snakes of South Carolina, the publication, Snakes of Georgia and South Carolina, is available for purchase at your county's Extension office or from Clemson's PSA Marketplace under "PSA Publications".