This small fish would help filter Narragansett Bay

By Stephen Medeiros

from the October, 2006 newsletter

In the past few years, much publicity and concern has been raised about the health and conditionmenhaden of Narragansett Bay, especially at times when dramatic events like fish and shellfish “kills” bring extra publicity to our waters.  When this happens, terms like hypoxia, nutrient loads and oxygen depletion become keywords that describe something terrible going on in our beloved Bay, and everyone hopes that our local scientists and environmental organizations can do something to fix the problems that cause these conditions.

The causes are many, such as our desire for green lawns, flushing toilets and the pressures of industry, which all contribute to the problem, but most of us are concerned enough to ensure that our government continues to work toward solutions. 

Organizations like the Narragansett Bay Commission which works to control water and sewage runoffs, DEM which regulates water quality and fisheries, and Save The Bay which watches over Bay waters and its creatures are all necessary to effect change.  As effectively as these organizations perform, however, no single magic bullet seems to exist that will suddenly create a perfect Narragansett Bay.  Only a combination of shore-based and water-based changes and strategies will work.  

There’s another aspect of a healthy Bay which doesn’t get as much attention, yet is equally important, and that is when all life in the Bay, contributes to a total, healthy “ecosystem.”   This requires a balance of plants, finfish and shellfish, contributing to the overall health of their underwater world. 

The system would be perfect if it wasn’t for the influence of humans having disturbed the Bay’s balance.  Fortunately, nature provides us with part of the solution for a healthier bay, and it’s so simple and readily available.  Yet it’s largely ignored.  It’s a toothless, silvery, non-edible fish called menhaden that arrives in our waters each spring, and has frequently been described as “the most important fish in the sea.”   

Menhaden, also known locally as pogies or bunker, migrate from the mid-Atlantic each year and usually enter Narragansett Bay in April by the millions.  A single school can number in the tens of thousands.  They are prized by recreational fishermen because they are the primary and most desired food source for most local game fish such as striped bass, bluefish squeteague, and summer flounder.  When the menhaden are plentiful in Narragansett Bay, so are the striped bass, drawing anglers from all over the region.

But that alone isn’t the reason why menhaden are so important to Narragansett Bay.  These fish, each weighing less than a pound, are enormous water filters, removing phytoplankton and detritus from the water, for this is what they eat.  Each adult fish can filter about four gallons of water a minute, removing harmful particles, leaving behind purer water that allows sunlight to penetrate and encourages the growth of aquatic plants, which in turn release oxygen into the water, encouraging the life of other fish and shellfish.  Imagine what millions of these fish can do to improve the quality of our Bay!

Although it would seem that menhaden should be an important part of the solution to a healthy Narragansett Bay, those fish just don’t get the opportunity to do their work.  Every year, as the menhaden arrive in our waters, so does the Massachusetts-based “pogey boat” (as recreational fisherman call it).  With the help of a spotter aircraft that will see the huge schools of menhaden from the air, their boat will spread a huge net, scooping up thousands of pounds of menhaden per day.  

Usually, by mid-June, after the boat has removed hundreds of thousands of pounds of adult menhaden (most of which is sold as lobster bait), the boat will leave Narragansett Bay, leaving behind only a fraction of the original number of these fish.

Imagine a special water treatment plant that is capable of filtering billions of gallons of Narragansett Bay water each year.  Imagine what that would cost.  Imagine if this was even possible.  This is the true value of menhaden!