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.
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.
ReplyDeleteI 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