Snakehead Terror!!!!

Invasive species have become a commonplace event in any exploration of the outside world. They take many forms; for example the plants Purple Loosestrife, Hogweed, and Japanese Knotweed, the insects Africanized Honeybees and Red Fire Ant, and the aquatic ecosystem destructors like Zebra Mussels and Chinese Mitten Crab. However, no other introduced species has garnered as much hype as the Snakehead fish (Channa argus).

Snakeheads were introduced either intentionally, by people who wish to use them for a food source (they are supposed to be very tasty), or unintentionally by aquarists whose fish had outgrown their aquarium and they set them free. The snakehead rapidly became a fish of legend, mainly because of it's ability to exist outside the realm of water, it has retained a plesiomorphic lung allowing it to breathe air out of an aqueous environment, and also can move on land (if the ground is wet) although how far they can "walk" is unknown. Other caveats to the snakehead is it's voracious appetite ( it can rapidly become the top predator of any freshwater body directly affecting the sportfishing industry), and amazing fecundity (50,000 eggs per female/breeding season). Other interesting facts are, despite what the Sci-Fi channel says, they can only reach lengths of 3-4 feet maximum, and they can eat birds and small mammals. The snakehead also protects its eggs and young (a rarity in native fishes), allowing for a higher survival rate. Once, they are present they are there to stay. The snakehead reproductive population is centered in three states Florida, Hawaii and Maryland. Although, snakeheads have been found in many other states including Massachusetts.

Why I selected this topic is that there is still much to be learned from the snakehead, and there is research going on right now that I have had the opportunity to assist in. The Potomac River has a significant population of snakeheads and the U.S. Fish and Wildlife (headed by John Odenkirk) has begun research on snakehead migration patterns using radio tagging and telemetry (of which I trained the crew). They have already discovered that the snakeheads have a distinct home range, they travel out to feed but return to a home base. The research team has also discovered a mass exodus of the fish during times of high water levels after a storm event. There is other research performed by the Smithsonian National Zoological Park involving tracking the genetic line of captured snakeheads to determine the reproduction line and spread of snakehead populations in the Potomac, as well as their genetic diversity.

There is still much to learn about these fish including studying their amazing ability to make sounds (very few freshwater species do this) when foraging for food, and perhaps at other times such as breeding and socializing. Invasive species, once established, will become a significant threat to the delicate balance of the ecosystem, and the only seminal control of such a threat will be through detailed knowledge of the behaviors and biological activities. There is a need for scientists to pursue research on any number of invasive species across the US.

Submitted by BEK