Friday, November 25, 2016


A couple of weeks ago, there was a big fish kill out around Shinnecock, here on Long Island.

It seems that there was a big—a very big—school of menhaden moving through Shinnecock Bay.  A bunch of bluefish found them, and chased the menhaden into the narrow confines of the Shinnecock Canal, where they became trapped after a falling tide caused the canal’s locks to close.

The tide continued to drop as October’s “super moon” pulled the water down to some of its lowest levels of the year.  It didn’t take long for the trapped menhaden to pull most of the oxygen out of the confined waters, and once that happened, it didn’t take very much longer for untold thousands of menhaden to suffocate and die.

What followed was an epic fish kill.

It could have been worse.  Local officials, alerted to what was going on, began to periodically open and close the locks, allowing fresh, oxygenated water to flow into the channel and allowing rafts of dead fish to float out into the bay.   Thanks to such quick action, a lot of the menhaden managed to survive, and escape into open water.

Still, a lot of them died.

A handful of local baymen arrived at the canal, hoping to gather up some of the dead fish for bait.  They reported that, as they ran through the waterway, the depthfinders on their boats showed a completely flat bottom.  In truth, its contours hadn’t changed.  Instead, so many dead fish had fallen to the bottom of the canal that the holes were filled in, and what once was a fairly rough bottom now appeared as an even plain of soon-to-decay bodies.

Out on the Internet, observers were quick to warn of disaster, and speculated as to what sort of chemical spill, algae bloom or other insult to the canal’s water quality lead to the deaths.  In their minds, such a mass dying could only be due to human intervention.

Folks who’d spent a lot of their time on the water knew better.  Menhaden are a forage fish that, when stocks are healthy, appear to be ubiquitous, with every bay, creek and tidal basin holding big schools of the fish from early spring into November.  When winters are warm, as last winter was, some will stick around all year.

When you have that many fish hanging around in shallow water, eventually, some are going to die.  In the case of menhaden, they tend to die in a very showy and spectacular (and often malodorous) fashion.

I grew up on Long Island Sound, in the town of Greenwich, Connecticut.  Back in the late 1960s and 1970s (and, from what I understand, through the 1980s and 1990s, too, though I left town in ’83 and so lack the personal knowledge), big schools of menhaden clogged the local harbors every summer.  

Every year, it was only a matter of time until schools of bluefish pushed a bunch of menhaden into thin water near the top of the tide where, just like the menhaden in the Shinnecock Canal, they suffocated and died once the tide fell.

That was fine when Greenwich harbor was still an industrial waterfront, with fuel tanks, gravel heaps and small factories lining its eastern shore, and the sewer plant at Grass Island never reliably perfumed the entire harbor whenever the west wind blew.  But by the mid-‘70s, pricey condos (generally sold at times of high tides and southerly breezes) and corporate offices had replaced the harbor’s traditional businesses.

The aroma of rotting menhaden wasn’t acceptable to new residents, whose olfactory systems never had to endure such insults when they lived on Manhattan’s West Side.  

Thus, members of the Greenwich Police Department’s Marine Division were given dip nets and pails, directed to cease their usual duties, and told to scoop dead fish out of the harbor, until the condo dwellers could again step out onto their buildings’ balconies and not smell a summer sea breeze that smelled like—well, what a real summer sea breeze is supposed to smell like, when the ecosystem is functioning as it should.

Because menhaden are supposed to die by the thousands, and do so again and again.

Like any vegetarian, their role in the ecosystem is to consume the nutrients contained in plankton and push them further along the food web, either when live or freshly dead menhaden are eaten by other fish, gulls, mink and the like, or when rotting menhaden are consumend by myriad invertebrates, from snails and grass shrimp to lobsters and crabs, which feast on the remains of the dead.

Chris Paparo is a naturalist who lives fairly close to the Shinnecock Canal.  Along with being an outdoor writer and very talented underwater (and above-water) photographer, he holds a degree in marine biology, and thus is uniquely qualified to comment on the menhaden kill.  He notes

“It was an unfortunate event for the fish that perished on that day, but through their death will come life.  Fish kills such as this are a natural event.  Yes, it took place in a man-made canal, but they occur around the world in naturally-occurring “dead ends” (creeks, marshes, etc.).  And although it seems wasteful, it is a windfall for many organisms.  Mortality can be very high for young of the year animals such as gulls, osprey, eagles, raccoons, foxes, etc.  Mom and Dad are no longer there to supply them with nourishment, and as winter approaches food becomes difficult to find.  Additionally, the caloric intake needed to stay warm increases as the temperature drops.  Meaning they need to find more food in the coming months than they needed to find during the summer months.
“As devastating of an event this fish kill was, within twenty-four hours it was back to business as normal for the marine life of the Shinnecock Canal and many organisms now have a huge advantage going into the first winter of their life.”
It has been so for a very long time.

A couple of years ago, my wife and I were wandering around the Wyoming back country, near the town of Kemmerer.  One morning we stopped by a fossil quarry, and spent half the day splitting limestone slabs, seeking to reveal the remains of creatures that had lived in and along the shores of a vast inland lake, that had stood in that spot 50 million years before.

What we found were the remains of fish, primarily two species belonging to the genus Knightia, extinct members of the herring family.

Knightia were small fish, while ranging in size from small minnows to a rare 10 inches, are generally found four to five inches long.  These herring-like fish probably fed on algae, diatoms, small crustaceans and insects.  Knightia themselves played an important part in the food chain as a food source for the larger fish in Fossil Lake.”

“From time to time, dozens of fish died simultaneously.  These mass mortalities may have been due to contamination of the upper water by hydrogen sulfide released by earthquakes or by seasonal turnover of lake waters; extremes of temperature or salinity; or stagnation caused by drought…”
The parallels to menhaden and menhaden kills are very clear.

We can be pretty sure that when Knightia died, other fish, and probably reptiles, birds and other creatures, fed on them, too. 

Fish kills have, for millions of years, been just another aspect of life.  So long as they are natural, they are nothing to lament.  Nor are they evidence that there are “too many” menhaden, and that there is no need to continue to conserve and manage the species, an argument that is too often heard.

Instead, menhaden kills, and the benefits that they bring, are nothing more than evidence that the system is operating as it should, and that managers should continue to manage the menhaden resource in a way that best assures that the species will continue to play its unique role in the food web throughout the foreseeable future.

1 comment:

  1. Great article! I myself having been on the water for 50+ years as a commercial fisherman, clam digger, scalloper etc, have seen many bunker kills, perfectly normal as you say.
    I remember the days when the bunker boats would be in LI sound and Gardners bays. I just returned from a sailing trip to the Chesapeake bay and happen to end up in Reedsville Va "the bunker capitol of the world" where they still harvest a very substainable fish stock with very little if any bycatch. Maybe we need to allow the bunker boats back into our waters to harvest what we have rather than letting it rot after a die off. Thanks