Thursday, January 5, 2012

Did the Chesapeake Bay Turn the Corner in 2011? by Dan Klotz

                                Sunrise off of Sandy Point State Park, MD. Credit: Dan Klotz

2011 may go down in history as the turning point for the Chesapeake Bay.  The largest estuary in the United States, the Bay’s watershed includes almost 20 percent of the country’s Atlantic coast and produces an estimated 500 million pounds of seafood every year.

In many ways, unfortunately, the Chesapeake Bay is ground zero when looking at the environmental impact of our food production. Inundated by pollution from factory farms, as well as sewage treatment plants, vehicle exhaust and power plant emissions, the Bay’s reputation as a high quality source of crabs and seafood has suffered over the years.

As chicken replaced beef as the number once source of protein on American dinner plates, the number of chickens crammed into factory farms—agricultural operations raising chickens and other farm animals on an industrial scale—has skyrocketed.  According to Food & Water Watch, Maryland has six factory-farmed broiler chickens (those raised for meat, not eggs) for every one person in the state. Think that’s a lot? Delaware has 19 factory-farmed broiler chickens for every human resident of the state.

The pollution from these facilities has been especially difficult to control.  The chicken manure and their bedding is dried in large piles and then spread as fertilizer on nearby farm fields.  Unfortunately, the amount of waste far exceeds the capacity of the crops to absorb the nutrients, and every time it rains the excess runs off the fields into nearby streams and then flows into the Chesapeake Bay.

According to the Chesapeake Bay Foundation, the runoff from farm fields accounts for 40 percent of the nitrogen and 50 percent of the phosphorous entering the Bay. As the key nutrients in fertilizer, nitrogen and phosphorous promote plant growth everywhere—and in water, this means the growth of algae blooms that consume the oxygen in the water.

In centuries past, marine species known as “filter feeders” would consume the algae and other types of plankton, keeping the water clean.  These filter feeders include well-known species such as oysters and mostly unknown species such as Atlantic menhaden.  But while the runoff from factory farms has vastly increased the amount of food for the filter feeders, overfishing has decimated their populations.

Atlantic menhaden, for example, once existed in vast quantities so large that schools once stretched for dozens of miles. A small innocuous fish no more than a foot in length, it can eat the algae in more than four gallons of water every minute.  Menhaden are the food of choice for seabirds, whales and marine mammals, and predator fish like the striped bass, blue fish, bluefin tuna, king mackerel, and Atlantic tarpon.

Unfortunately, more menhaden are caught on the U.S. Eastern seaboard than any other species, even though they are not caught for food. Instead, more than three quarters of this catch is brought to a processing factory at the mouth of the Chesapeake where the fish are “reduced” to oil—for omega 3 fatty acid pills—as well as fertilizer, factory farm feed, pet food, lipstick, and other commercial products.

Atlantic menhaden image courtesy of U.S. Fish and Wildlife Service.

Scientists from the Virginia Institute of Marine Sciences looked at the number of menhaden thought to be in Chesapeake Bay and then examined the amount of algae thought to be growing in the Bay’s waters.  They concluded that there weren’t enough menhaden to slurp up all the algae, and their study was cited by the commercial fishing industry as proof that menhaden had a limited ecological role as it fought against efforts to lower its annual catch.

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