By Paul Spitzer, PhD | Reprinted from the Atlantic Journal

New regulations clamping down on the commercial menhaden harvest are working—last fall’s Chesapeake Bay loon count offers proof.

Autumn brings all manner of migratory waterfowl to the Bay, loons among them, and they are partial to the Bay’s annual crop of “peanut” menhaden (fish) nurtured on plankton in countless creeks over the warm summer.

By fall, these fish are about five inches long, and already they form dense schools. The newly arrived loons practice an “intercept fishery” on the peanuts, forming noisy cooperative flocks in the lower reaches of some Bay tributaries. They act like a live fishing net, most of them underwater at any given time, surfacing only to gulp air for a second then dive again.

What you’re seeing here are cooperative predation tactics by highly intelligent, long-lived water masters who know how to make the most of their annual Chesapeake stopover. But, for this to work, the peanut menhaden prey base must be abundant, and that has been deficient for some twenty years.

Since the early 1990s, menhaden have been overfished. One indicator of that was the reduction in the Bay’s annual loon count.

When the Atlantic States Marine Fisheries Commission finally moved in 2012 to institute a biologically realistic cap on the menhaden harvest, I had hopes that my lifetime studies of loons and ospreys would demonstrate menhaden recovery. I am pleased to report that 2014 observations of both species’ abundance say a resounding yes!

For the first time in two decades, I tallied four hundred loons on a calm afternoon last November, most of them in feeding flocks of thirty to one hundred ten birds on the Choptank River and Eastern Bay.

Ecologically speaking, menhaden spin straw into gold. As our civilization drenches our coastal waters with nutrients, plankton populations swell, ultimately depleting dissolved oxygen and creating biological hazards like dead zones and red tides. Menhaden is a filter-feeder, meaning that it virtually sucks up plankton and passes it up the food chain.

Dr. Paul Spitzer presented this material at the North American Loon Symposium. Paul reminds us that not only is it important for our northern lakes to remain healthy, but loons also depend on these Atlantic coastal ecosystems to remain healthy and diverse as well.


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