Food
Chain in Motion -- Kevin Sullivan's Tale
In
my 27 years as a special agent with the National Marine Fisheries
Service Office ofLaw Enforcement, I've spent a lot of time on
the ocean. But the single most spectacular event I witnessed
took place over twenty years ago in what is now the Stellwagen
Bank National Marine Sanctuary.
I
can't quite recall the date. I believe it was 1978, perhaps
1979. I vividly remember the day. It was a crisp autumn afternoon.
With little wind the water was like a mirror reflecting the
west heading sun. Long, dark shadows followed the Massachusetts
Environmental Police patrol boat. I had joined a day-long mission
with two environmental police officers. We were on the lookout
for fishing vessels taking more than their legal share of giant
bluefin tuna.
Stellwagen
Bank, which had not yet been designated as a National Marine
Sanctuary, was, and still is, a popular fishing spot for the
giant fish. You have to understand a bit about giant bluefin
tuna to see why a fishermen would break the law to catch them.
True to their name, giant bluefin tuna are enormous creatures,
weighing as much as 1200 pounds. They can swim at speeds of
up to fifty miles per hour. These fish are called "highly migratory
species" due to their lengthy journeys from sea to shining sea.
Even back then, fisherman make a pretty penny selling these
fish in Japanese markets. They'd place the fish individually
into large wooden coffins, load them onto a 747, then ship them
straight to Tokyo, where dealers would pay up to 25 dollars
a pound for them.
If
you do the math you'll understand why catching just one giant
bluefin tuna makes for a profitable day at sea. For obvious
reasons, some fisherman would like to catch more than one. But
by federal law, a fishing vessel can take only one giant bluefin
tuna per day. Tuna stocks had become unstable in the mid-70's
due to overexploitation around the world, especially by distant
water longliners. Scientists feared that populations would collapse
if fishing pressure kept up. The state officers and I wanted
to see to it that this didn't happen. We weren't just enforcing
the law out there; we were ensuring the survival of the majestic
giant bluefin tuna. At the same time, we had a genuine concern
for maintaining "a level playingfield" for the fishers who expend
significant time and money in the hunt for their valuable prize.
Those who fail to achieve their catch are said to have been
"tuna wishing".
Well,
the two officers and I were merrily making our way along the
southwest corner of the bank, not too far from Provincetown.
As always, we tried to be aware of breaking water to avoid collisions
with marine mammals such as the highly endangered right whale
that frequents the Bank. One of us spied white water splashing
about a three iron from our boat. It was a school of very scared
sand eels leaping for their lives above the surface of the water
as hungry bluefish cunningly circled underneath awaiting their
appetizers. The jumping sand eels were a familiar sight, typical
of bluefish feeding frenzies. Pound for pound bluefish are probably
the fiercest fighters in the sea. But they were no match for
what we then saw: a school of bluefin tunas bursting though
the water just behind the bluefish. The table had turned. The
predators became the prey. The bluefish leapt from the water,
frantically seeking escape from the powerful jaws of the encroaching
tunas.
Back
on the ship we'd fallen silent as the spectacle of the food-chain
in action unfolded with the shocking appearance of the oceans÷
ultimate force. The tell-tale traits of bright white on black
and the high triangle fins instantly announced the presence
of killer whales in hot pursuit of the marauding bluefins. Killer
whales aren't so common on the bank, but when they're there,
they like nothing more than a bluefin tuna dinner.
My
best guess is that the scene lasted about thirty seconds. I
lost track of the time, though. To me, time stood still, as
if the whole event was a snapshot of a natural process. We could
see every level of the food chain at work, except for the microscopic
plant plankton and the somewhat larger animal plankton that
serves as the sand eels' food. Looking back, I realize that
if I'd had a good camera handy, I could have taken a picture
that would have enabled me to retire twenty years early!
