18 Fall 2013 ; cbf.org
Tom Pelton is Senior Writer and
Investigative Reporter for the
Chesapeake Bay Foundation.
Read his blog, Bay Daily, at
Red drum are a popular sport fish off the
Carolinas and Florida. Normally, they are
unusual in the upper Chesapeake Bay and
seasonal visitors in the lower Bay. Oddly,
however, last year, fishermen in Virginia
and Maryland reported catching record-shattering numbers of red drum— 2. 7 million of them, mostly juvenile “puppy
drum” about a foot long. That was more
than thirty times the number of red drum
caught the year before, according to state
The sudden and dramatic increase of this
southern species in the Chesapeake Bay
could have played a role in the disappearance of hundreds of millions of young blue
crabs last year, scientists theorize. Drum
love to eat juvenile crabs.
But why the drum boom? Lee Paramore, a
biologist with the North Carolina Division
of Marine Fisheries who studies red drum,
has a theory. He believes unusual weather
conditions in 2011 spurred a population
explosion that spread from North Carolina
into Virginia and Maryland.
“One thing that happened of interest in 2011
was Hurricane Irene,” Paramore said. “The
time that Hurricane Irene passed through
was exactly during the peak spawn of red
drum, which occurs in late August.”
Not everyone knows that hurricanes affect
creatures beneath the waves. But as it turns
out, red drum are highly dependent on favorable winds and currents for their survival,
Paramore said. Winds from the east blow
drum eggs and larvae from open waters—
where the fish spawn—into more protected
bays and inlets, where the fish find shelter.
Hurricane Irene had these winds in abundance. So the drum survived and grew in
abundance in the Carolinas, Paramore said.
“That is entirely possible,” Dr. Susan
Lowerre-Barbieri, a biologist with the
Florida Fish and Wildlife Conservation
Commission, said of the connection
between the hurricane and the drum explo-
sion. “The eggs of drum are buoyant. And if
you happen to get a hurricane year and
more easterly winds, that should help the
currents take more of the eggs into nursery
areas where they would be more protected.”
In Florida, a clear pattern has emerged, said
Dr. Lowerre-Barbieri. When drum popula-
tions rise, crab populations fall, because
more are consumed by the fish, she said.
“Predation probably played a large part in
the decline of juvenile crabs,” said Dr.
Romuald Lipcius, Professor of Marine
Science at the Virginia Institute of Marine
Science. “The red drum in particular are
voracious, generalist predators, and they
can consume large numbers of juvenile
An unusually warm winter in 2011-2012
may also have contributed to the large
number of drum in the Bay last year, said
Susanna Musick, Marine Recreation
Specialist with the Virginia Institute of
“Usually what happens is that red drum
migrate out of the Bay in the winter, and
then come back in the spring,” Musick said.
“But because of the warm temperatures, we
had an unusually high number of red drum
that stuck around in the Bay. There was
nearly a year-round presence of them.”
Bill Goldsborough, CBF’s Director of
Fisheries, said global warming could
potentially shift more of this southern fish
into the Bay over time.
“I do think there are climate change effects
wrapped up in this,” Goldsborough said.
“People caught red drum off Cape Cod last
year. I’ve never heard of red drum being
caught north of New Jersey.”
The increase in drum last year was witnessed by anglers across the Chesapeake
region. In Maryland, fishermen reported
catching and releasing more than
240,000 red drum, according to the
Maryland Department of Natural
Resources. Many were released because
they were smaller than the legal size minimum of 18 inches.
“A lot of years we don’t see hardly any red
drum,” said Harry Rickabaugh, a biologist
with the state agency. “We never see numbers like this.”
The population surge is also evidence of a
turnaround caused by science-based regulation. Red drum were nearly wiped out
during the 1980s when Cajun-style “
blackened red fish” became trendy in restaurants. A ban on commercial harvesting in
many areas allowed a rebound in red drum
during the 1990s.
“It is quite a success story,” Dr. Lowerre-Barbieri said. “It’s amazing that there was
the political will to take such measures in
the 1980s and close down the fisheries and
protect this stock.”
But everything in an ecosystem is linked.
Scientific surveys during the winter of 2011-
2012 estimated there were 581 million juvenile blue crabs in the Bay, the highest number in more than 20 years. But then the blue
crab harvests in 2012 and 2013 were low.
This discrepancy suggests that something
was eating large numbers of young crabs
before they could grow large enough to be
caught, said Lynn Fegley, Deputy Director of
the Fisheries Service at the Maryland
Department of Natural Resources.
Predatory fish, including red drum and
striped bass, are likely suspects in this crab
disappearance, Fegley said. Other likely
culprits are the blue crabs themselves,
because the species is notoriously cannibalistic. A decline in Bay grasses gave young
crabs fewer places to hide from their parents and other predators.
In addition, wind and weather conditions
unfavorable to the survival of crab larvae
likely contributed to a drop in juvenile
crabs in the Bay between 2012 and 2013,
Winds blew fair for drum, then turned foul
for crabs. The silver lining to all this stormy
weather is that the cascading river of gold-en-red fish flowed from southern waters
into the Chesapeake Bay.
When drum populations rise,
crab populations fall.
DR. SUSAN LOWERRE-BARBIERI