Northern Snakehead Study In Maryland Shows Major Reductions In Fish Stocks

The northern snakehead, dubbed the “frankenfish”, is an invasive species, first discovered in Maryland’s Potomac river in 2004.

Since then there has been disagreements between fishermen, DNR and scientists over the detrimental effects of this invasive species. There are many “bucket biologists” that feel the fish is not hurting our freshwater ecosystems, but scientists recently discovered fish population reductions in the Blackwater River areas of Maryland as high as 97%. Completely different communities in northern snakehead infested waters are now occurring, compared to the studies before snakeheads were an issue. Studies of fish populations were conducted a couple years after their discovery and just recently. The results speak for themselves.

Study excerpt …
Northern Snakehead is an invasive species initially discovered in the Potomac River in 2004, but has since spread to most major river systems of the Chesapeake Bay. In 2012, Northern Snakehead was first reported from the Blackwater River drainage on the eastern shore of Maryland. Fish community surveys were conducted in Blackwater River and Little Blackwater River in 2006 and 2007, before the establishment of Northern Snakehead there. Because of minimal habitat changes owed to protection by Blackwater National Wildlife Refuge, this dataset enabled us to document changes in the fish community that could be attributed to the establishment of Northern Snakehead. We replicated the 2006 and 2007 surveys (preSnakehead) over a year from 2018-2019 (post-Snakehead). Over all sampling periods we caught 35 species (32 fish species and 3 invertebrate species) totaling over 50,000 individuals. Of 21 species that were captured both pre- and post-Snakehead, 17 declined in relative abundance with percent reductions ranging from 30%-97%.
Read The Full Report here …. Comparison of fish community within the Blackwater River watershed before and after establishment of Northern Snakehead.

I think the northern snakehead is detrimental to small ecosystems. It is possible they could be controlled naturally in larger ecosystems. I just don’t think a small body of water can sustain such an aggressive predatory fish. More so than anything we have naturally occurring in our waters.
Blue catfish would be and is another concern as an invasive species for Maryland and Delaware. There have been control efforts by both states. Maryland DNR at one point offered money for the dead fish. Maryland also saw a massive increase in snakeheads in the Conowingo Dam fish lift. Last year Delaware added northern snakehead to the state record lists, which was quickly set and broken.