Perry Jeffries, Professor Emeritus
Graduate School of Oceanography
Perry Jeffries earned BS and MS degrees
at URI, and a PhD degree at Rutgers University. He came to the Narragansett
Marine Laboratory as an Assistant Professor of Oceanography. His
research interests include coastal ecosystems (structure and patterns
of change), zooplankton distribution and abundance, and fatty acid
and amino acid pools in relation to environmental conditions.
It was a cold and stormy nightJanuary
6, 1959 when the Narragansett Marine Laboratory, predecessor
to the Graduate School of Oceanography (GSO), burned to the ground.
Everything was lost, including irreplaceable records and a manuscript
that Marie P. Fish had left on her desk for a final check. Her
husband, Charles J. Fish, founder and director of the lab, moved
his staff to the old Washington County Jail in Kingston and started
As the ashes cooled, a research
program on the bottom fishes and invertebrates in Narragansett
Bay and Rhode Island Sound emerged. Marie Fish needed information
about seasonal migrations to correlate with recordings of underwater
sound, a matter of critical interest to the U.S. Navy. Charles
Fish, whose classic dissertation on the plankton of the Woods
Hole Region set the bar for seasonal studies, realized an extra
benefit. Long-term changes in a complex of interacting populations
inhabiting coastal waters could be measured rather than left to
anecdotal accounts. When Charles Fish retired in 1966, he gave
me his data, and I have worked to maintain a program designed
to perpetuate his ideas.
Every week since January 1959,
a trawler has left Wickford Harbor and made a 30-minute otter
tow in mid-Narragansett Bay and in Rhode Island Sound. The net
collects animals (three inches and larger) living on and just
above the bottom. We measure water temperature and count and weigh
each species. Winter flounder are given special attention: individuals
are measured and sex is noted.
Because we do the same thing week
after week, we can observe gradual and long-term changes. No record
comparable to this 42-year-old data set exists for any coastal
area; thus the data become more valuable every year.
Annual abundance is the total of
average monthly catches for a species. Thus, for a year-round
species, up to 52 samples reduce to a single estimate of abundance.
Sampling was less frequent during the early days but now, thanks
to Captain Tom Puckett's dedication aboard the trawler Cap'n
Bert and several generations of outstanding graduate assistants,
we rarely miss a week. The record is available for management
purposes and, since 1999, all have had access to it.
The local scientific community
requests specimens from the trawl, and surprising uses have been
found for our temperature data. I could hear a sigh of relief
when I gave bottom water temperatures to the engineers of the
Jamestown Verrazano Bridge who needed to take temperature into
consideration before mixing and pouring concrete in the middle
The winter flounder confounds me
as I attempt to explain the changes that occur among the 24 species
that make up 99 percent of the year-round catch. Winter flounder
once made up 50 percent of the inshore fisherman's income, but
the population is now a mere vestige of its former glory. Intuition
tells me that an 80 percent decline from the first to the fourth
decade of our program is not entirely due to overfishing and pollutiontwo
common explanations for problems in coastal waters.
After the flounder population reached
a low point in 1976, I published a paper with Bill Johnson, a
GSO graduate student in 1980 who assisted with the trawl, reporting
a correlation between warmer winters and the flounder's 86 percent
decline from a peak in 1968. But correlation does not prove causation,
and warming from 1971 through 1975 amounted to about 2°C,
which seemed insufficient to produce a major biological effect
(see Figs. 1 and 2). Besides, there was little ancillary information
for corroboration, and back then no one was talking about climatic
warming in coastal waters.
I learned from Candace Oviatt,
director of the Marine Ecosystem Research Laboratory, that sand
shrimp raised havoc in outdoor aquaria by eating anything they
could get their claws on. Was this inch-long terror, previously
capable of feeding only during warmer months, now able to feed
in winter? If so, the flounder's reproductive efforts would be
After the flounder population recovered
briefly (19781983), I proposed a theory in a paper with
Mark Terceiro, a GSO doctoral student in 1985, who used part of
the trawl record for his dissertation. We combined warming and
predation to explain the flounder's behavior. Winter flounder
have an unusual ability to repopulate in estuaries at extremely
low temperatures, a time when predators are either offshore or
inactive. Shrimp have adapted, and since 1970, following warmer
winters have invaded the flounder's refuge, devouring its eggs
and larvae. Extrapolating Sandra Whitehouse's 1994 GSO dissertation
results on shrimp feeding rates, I calculated that predation might
well destroy all the young flounder produced during a single winter
in Narragansett Bay.
To strengthen our theory, we needed
evidence that shrimp thrived during winter. Soon thousands of
shrimp appeared, entangled in the trawl's manila ropes. Our skeptics
would not be stilled until measurements were made of shrimp feeding
rates at low temperatures. Some biologists insist that fishing
pressure is the controlling factor. This cannot be true because
the flounder population recovered in the late 1970s, only to collapse
again as the warming trend recurred (compare Figs. 1 and 2).
Studies on plaice in the North
Sea bolstered the shrimp theory. Plaice belong to the same genus
as winter flounder, and they prosper following cold winters. North
Sea shrimp belong to the same genus as sand shrimp, and they fare
well during warm winters, feeding on plaice eggs and larvae. The
predator-prey genera are the same, only the species differ. I
call it a congeneric correspondence: Similar species interact
in the same way on both sides of the North Atlantic.
From the early 1980s on, when the
flounder population collapsed a second time, unusual events took
place among the Bay's crabs: Sand crabs appeared in January and
commenced to shed. Previously, this species and the related Jonah
crab, along with other invertebrates, waited until spring to begin
their migration from the ocean.
The flounder population entered
the new millennium at less than 10 percent of the total catch.
Against a background of warmer winters, the winter flounder's
future is not promising.
It follows that the myriad bottom
foods in Narragansett Bay once supporting winter flounder have
become available for others, which may explain increases of migratory
lobsters, crabs, squid, butterfish, and scup. Outsiders, chiefly
warm water visitors to the Bay, have taken over bottom habitats.
Note how scup filled in the gaps left by winter flounder (see
Fig. 2). In 1995, it looked as if invertebrates would overrun
both the Bay and Rhode Island Sound. Recently, however, their
numbers have fallen off. Body size is small and the species are
less desirable, so commercial value is less than it was during
the flounder's halcyon days (see Fig. 3).
One exception is lobster, which
defies all explanation. How long can that population endure? Several
years ago, I saw three offshore trawlers at the mouth of the Bay,
dragging the bottom with their huge nets; a fourth was leaving.
What were they after? Not fish. The catch would not have been
enough to cover fuel costs. It must have been lobsters, whose
numbers had reached an all-time high in 1992 (see Fig. 4). Then
came an oil spill that killed millions of lobsters.
I wonder when outdated fishery
economics, ineffective management, and perhaps even greed will
catch up with our splendid crustacean. The population is unstable;
its numbers in the Bay dropped one-half in a single year (199899),
and it remained there through 2000. Perhaps its limit has been
reached (see Fig. 4).
A major conclusion emerges: The
winter flounder's rise and fall are part of a bigger whole that
changes continuously. Prior to 1970, the controlling dynamics
were Bay-centered. The balance shifted to Rhode Island Sound in
the early 1970s, went back to the Bay after two cold winters,
and finally returned to R.I. Sound in the early 1980s, where it
has remained ever since. Reflecting this dynamic balance, the
24 major species fall into five groups for the 19591998
Group 1. Progressive increases: butterfish, lobster, squid, Atlantic
herring, little skate, striped sea robin, fourspot flounder;
Group 2. Multimodal (several) increases: cancer crabs, conch,
spider crab, Mantis shrimp, scup;
Group 3. Indeterminate: horseshoe crab, starfish, fluke, ocean
pout, red hake;
Group 4. Multimodal declines: winter flounder, windowpane flounder,
Group 5. Progressive decreases: cunner, tautog, northern sea robin,
The Bay's winter flounder population
established a pattern that others seemed to follow. Flounder thrived
twice following cold winters, but each time, winters soon warmed,
and the populations waned. During the flounder's first collapse,
scup, a warm-water species, migrated more strongly into the Bay
to take its place. Invertebrates and butterfish, another warm-water
migrant, characterized the aftermath of the flounder's second
For migrating bird populations,
the eminent ecologist Robert MacArthur would have called this
Bay-Sound relation an expression of his Principle of Equal Opportunitygo
to the habitat where the getting is good. We now know that that
principle applies to fish and bottom invertebrates as well as
to birds. You might say that the Bay has less control of its destiny
as warm water visitors take over.
Group 5 has the big losers in the
numbers game. Cunner and tautog are related, though the former
is a pest for recreational fishermen and the latter is a commercially
valuable species. Longhorn sculpin reproduce during winter, so
their eggs and larvae may also fall prey to shrimp. The demise
of the cunner and northern sea robin is a mystery.
Deciphering the information presented
by the trawl data provides me with more than statistics and ecological
theory. Its patterns unveil the whole that every oceanographer
knows is the proper way to study an issue. This was Charles Fish's
credo. He rebuilt a laboratory to support a graduate program that
embodies this ideal, making certain that the message is clear
for generations to come. Credit also goes to the administration
of the Graduate School of Oceanography and to the state of Rhode
Island for supporting this study.