December 6, 2010

Menhaden are the most important, though humble, fish in the sea

"Bunker" reads the sign, hand-printed on cardboard, above the cooler in Ocracoke Island’s Tradewinds Bait and Tackle Shop. A fisherman comes in, wind-blown and slightly damp, and opens the cooler.

Studying the heaped up silvery fish, he looks up at the gentleman behind the counter.

"Are these fresh?"

Receiving an affirmative "caught this morning," he scoops several into a bag and lays them on the scale, which registers $1.75 per pound.

He will cut them into chunks and use them to go fishing for prize red drum later this afternoon.

Meanwhile, the fisherman’s wife, waiting back at the motel, takes out her bag of vitamins and health supplements. She holds up a bottle of omega-3 rich fish oil and reads it before removing a capsule and popping it into her mouth. The label says that it can help prevent heart disease, Alzheimer’s, and depression.

She takes out another container likewise labeled to contain fish oil. It has a picture of a healthy dog on it, and promises to improve your dog’s skin condition and reduce shedding. She pops one of these pills down her Labrador retriever’s throat. Were she to look closer, she would see that the little fish pictured on the boxes looks exactly like the fish her husband is buying for bait.

The bunker at Tradewinds is otherwise known as menhaden, fatbacks, alewives, or Brevoortia tyrannus to scientists and had been caught as bycatch in one of the local fisherman’s gill nets.

Menhaden are not considered a major fishery at Ocracoke. When netted in spring, they are often sold to crabbers to use as bait, and they are popular with sports fishermen, such as the ones at Tradewinds.

Nationally, there is a huge demand for these small herring, and according to the Chesapeake Bay Ecological Foundation, they are the second most important species harvested in the United States (after the Pacific pollock) in terms of quantity.

For years they have been caught and processed for use as fertilizer -- the name menhaden actually derives from the Algonquin word for fertilizer, or manure --, dog and chicken food, oil, and solubles. According to writer Tim Padgett, "recent studies indicate that overfishing has been occurring for decades..."

A new development in health research has recently brought about another huge market for these fish, along with other oily fish, such as sardines, mackerel, and salmon. Vast quantities are harvested to be processed, bottled and marketed as omega-3 rich fatty acids, or fish oil. Since 2006, according to Padgett, the U.S. market for these supplements has doubled, and American consumers spend billions of dollars not just on the supplements themselves but for products such as orange juice, baby food, and cereals with fish oils added.

And while this may be good for human health, it could be catastrophic for the species and for the marine ecosystems dependent on it.

According to marine ecologists, menhaden are a critical link in the food chain, providing food for larger fish, for birds such as pelicans and loons, and for dolphins and harbor seals. They also play an important part in keeping the oceans clean. They are filter-feeders, eating algae which, while good for human health, can cause oxygen-depleting algal blooms which lead to dead zones in Atlantic and Gulf waters. Menhaden can filter up to seven gallons of water per minute as they feed.

Biologist and author Theodosius Dobzhansky, expressing his impression of their importance, said that "nothing in fisheries makes sense except in light of the menhaden."

Atlantic menhaden belong to the family of bony fish known as clupeidai, or herrings, which are highly specialized schooling fish with primitive origins. Small fish, seldom reaching more than 14 inches, they range from Nova Scotia to Florida. They have long, closely set gill rakers that allow them to filter out the plankton which makes up most of their diet. Spawning in the ocean in winter, they count on winds and currents to carry their eggs and larvae up estuarine creeks to brackish waters where the juveniles feed and grow before returning to the sounds and later the ocean. 

Professor H. Bruce Franklin of Rutgers University thought the menhaden important enough to author a book about it in 2008, “The Most Important Fish in the Sea.” In it, he points out that menhaden are being fished out on a global scale and may be in danger of extinction.

At one time menhaden were observed in schools several miles long and millions of fish deep. Soon after the Civil War, the purse seine was introduced so that they could be netted in large numbers, and their decline began. While they have remained fairly stable since the 1050s, they have never returned to their pre-factory fishing days.

There used to be a number of menhaden processing factories on the Atlantic coast, including one at Beaufort, N.C., which provided hundreds of jobs for residents there. There is only one shoreside reduction plant left now, located in the Chesapeake Bay at Reedsville, Va.

Ninety percent of the country’s menhaden are now caught and processed by a company in Texas. The Houston-based fish oil company, "Omega Protein," has been banned from the waters of 13 Atlantic states because of concerns about the fish’s sustainability.

If consuming fish oil products could be bad for the ocean, what options do health conscious people have?

There are several possibilities. Flaxseed and canola oils contain alphalinolenic acid (ALA), one of the omega-3 acids in fish oil. They do not, however, have docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA), which are probably the more beneficial of the acids.

The answer may be in harvesting or producing algae, the same algae from which oily fish derive their omega-3-rich acids when they are filter-feeding. It is possible, according to Padgett’s article on going green, to derive most of the benefits, including DHA and EPA, from the algae itself, instead of from the fish which feed on them.

Several companies, including a Maryland biotech company known as Martek, are experimenting with farming different algal strains in huge tanks, and are marketing a healthful combination of algae and seed oils for public consumption.

Public awareness of the importance of the little fish known as bunker, or menhaden, and their plight, along with knowledge about other options for obtaining omega-3 acids, could prevent destructive overfishing and the loss of one of our most important marine species.

 Comments are always welcomed!

     Subject :

     Name :  (required)

     Email :  (required, will not be published)

     City :   (required)    State :   (required)

     Your Comments:

May be posted on the Letters to the Editor page at the discretion of the editor.