Pollution has long been known to have a harmful effect on marine life, including the fish we eat. Mercury, PCBs and other toxins have been found in fatty fish such as salmon, tuna and halibut for years, putting seafood-lovers at risk of ingesting dangerous chemicals at well. Now, experts say that pollution is damaging the Neuse River in North Carolina, killing off a significant part of the local ecosystem.
Atlantic menhaden are a small, silvery type of fish belonging to the herring family. Native to rivers along the Eastern Seaboard of the United States, dead Atlantic menhaden now cover the riverbanks of the Neuse River. Experts estimate that the number of dead fish will soon reach 200,000.
The fish are reportedly dying from a lack of oxygen caused by excessive nutrients present in the water, including phosphorus and nitrogen. This increased nitrogen also causes algae to bloom in the water, growing a bacterium calledAphanomyces Invadans, or A. Invadans. As a filter feeder known for its ability to purify ocean and river water, menhaden consume this bacteria as they hunt for the plankton that makes up their diet. From there, the bacterium will kill the fish from the inside out, leaving a small hole resembling a bite at the animal’s rectum as it eats its way out of the body and back into the river. At first, the younger fish made up the majority of the affected population, but now, area riverkeepers are reporting that they have found more adults onshore.
While no other species have died thus far, the Atlantic menhaden’s important place in the Neuse River ecosystem puts much of the area’s marine life at risk. Menhaden are prey for a number of fish you might expect to see at a local restaurant — including bluefish, striped bass, cod, haddock, halibut, mackerel, swordfish and salmon — which could affect the availability of some of North Carolina’s most popular seafood. Moreover, while Atlantic menhaden is typically considered inedible, it is now a primary material used in fish oil supplements. Although the A. Invadans only affects fish, this could drastically reduce the amount that can be used to create supplements and other products.
To address the problem, the Neuse River Foundation is reportedly creating a workshop for homeowners along the river’s banks, whose use of fertilizers and pesticides is likely affecting the water’s oxygen and nitrogen levels. Riverkeepers have remarked that it will take the cooperation of the entire community to reduce the number of dead menhaden.