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by
Erik Zlokovitz
Summers off the New England Coast,
winters in North Carolina... It's a way of life for many. And who could argue -
both Nantucket and Martha's Vineyard are wonderful places to spend the warmer
months, and the Outer Banks aren't so bad in February...
However we're talking fish here. Each year, the
coastal migratory striped bass that visit the Chesapeake to spawn in the spring
hit the road for the chilly waters of the North Atlantic by late May, then
return south to the waters off coastal North Carolina for the winter months. And
for the past 17 years, so has a crew of fisheries biologists from Maryland's
Department of Natural Resources (DNR).
Along with a handful of sister agencies, DNR
follows the striped bass down south of the coast of Cape Hatteras, hoping for
some warm(er) weather while partaking of a little scientific research under the
auspices of the annual winter Southeast Area Monitoring and Assessment Program (SEAMAP)
tagging cruise. Since 1988, this effort has provided a wealth of
fishery-independent data for many species that inhabit the Mid-Atlantic coast.
When it was originally developed, the main
purpose of the cruise was to capture and tag as many striped bass as possible.
The Outer Banks are an important wintering and feeding area for stocks of
Atlantic striped bass, including those from the Chesapeake. In early spring,
typically in late February and March, the population begins migrating back north
and inland to their native spawning grounds. The majority of these fish will
swim into the spawning reaches of the Chesapeake Bay tributaries, while others
will head to Albemarle Sound and the Roanoke River, or even further north to the
Delaware and Hudson Rivers.
This year's cruise took place on the Duke
Marine Laboratory Research Vessel (R/V) CAPE HATTERAS from January 15-25. The
National Oceanic and Atmospheric Administration (NOAA) ship OREGON II, which has
been used on the majority of tagging cruises, was in dry dock for refitting and
not available for this year's trip. Participants on this year's cruise
represented several state, federal and academic agencies, including DNR, NOAA,
the U.S. Fish and Wildlife Service (USFWS), the Atlantic States Marine Fisheries
Commission (ASMFC), the North Carolina Division of Marine Fisheries (NCDMF), and
East Carolina University (ECU).
Getting to Work
The
R/V CAPE HATTERAS employed one 65-foot long bottom trawl for 10- to 30-minute
tows and worked along the Outer Banks, one to nine miles offshore. This year's
cruise proved to be a success, with biologists tagging 2,708 striped bass, the
fourth highest number in the survey's history. This number is notable because it
exceeded the existing long-term 16-year average catch of 1,914 striped bass
while using only one net (in most past cruises, two nets were deployed). The
primary focus was on the zone between Nag's Head and Corolla northward to the
Virginia state line; however the highest concentrations were found offshore of
Kitty Hawk and Corolla in 40 to 50 feet of water. Toward the end of the trip,
gear was also deployed further south near Oregon Inlet, where a booming
recreational fishery for striped bass has developed during the last few winters.
Over the years, data and samples have been
collected on an increasing number of species that are routinely encountered on
the cruise, and the operation has
evolved
into a true multi-species program. Species sampled include Atlantic sturgeon,
spiny and smooth dogfishes, summer and southern flounder, red drum, monkfish,
weakfish, spotted sea trout, hickory shad, American shad, Atlantic mackerel,
skate and horseshoe crabs. (A major effort is also under way to tag as many
spiny dogfish as possible, and more than 3,000 were tagged in the sixth year of
a cooperative effort between the National Marine Fisheries Service, the
Northeast Fisheries Science Center, ECU and the Mid-Atlantic Fishery Management
Council.) Overall, the scientific party and crew of the R/V CAPE HATTERAS
processed a total of 8,450 fish representing 17 different species.
No Time for Shuffleboard
This is hardly the stuff of a Carnival cruise. There is no pool to bask beside,
no midnight buffet, and no live entertainment, except perhaps for the weary soul
who breaks into song at 4 a.m. to counter the chill and stay awake. Scientists
are divided into two watch groups working round-the-clock and switching up every
six hours. Most unpopular is the "graveyard shift" of midnight to 6 a.m., which
often means cold and miserable conditions on deck.
Each
watch group or tagging team has a watch leader who serves as deck boss and
foreman, maintaining the steady flow of work. Within each group are one or two
taggers, a data recorder, "fish wranglers" and sample collectors. Fish wranglers
are in charge of lifting heavy and often vigorous striped bass off the deck or
out of the holding tanks and feeding them in a steady stream to the taggers. The
taggers then measure the fish, use a metal detector to scan the cheek area for
hatchery-implanted coded wire tags, remove a scale sample for aging purposes,
insert tags into the striped bass, and finally, release them over the side of
the ship. Quite a process and one that requires both speed and efficiency. I
served as second tagger and principal striped bass data coordinator on the
morning and evening shifts.
Bill Cole of USFWS has been the chief scientist
and coordinator of the cruise since its inception in 1988. He was often seen
discussing fishing strategy and charts with the captain and first mate in the
wheelhouse or pacing around the wet lab and working deck. He is famous for his
Ahab-like intensity in pursuing schools of striped bass.
Roger Zirlott, Chief Bosun of the OREGON II,
out of Pascagoula, MS, served as the chief fisherman and NOAA representative.
His seaman skills on deck and knowledge of the fishing gear and vessel operation
were crucial to the successful outcome of the cruise.
Most
hauls contained many small members of the drum family: croaker, spot, kingfish,
spotted sea trout and weakfish. Commonly encountered bottom fish included
spotted hake and summer flounder. Baitfish such as menhaden, bay anchovy,
Atlantic herring, Atlantic mackerel, and hickory shad were abundant, which
helped to attract and keep striped bass in the area. Various species of skate,
starfish, crabs, whelks and other small bottom-dwelling species were also
encountered. Smooth dogfish were noticeably absent, and numbers of loligo squid
were down significantly (a major disappointment to the cook and other fans of
calamari onboard the vessel).
Unfortunately, we did not come across large
numbers of more "exotic" species. Only one Atlantic sturgeon was captured and
tagged this year, a major drop from previous cruises (the record number of
sturgeon captured and tagged was 22 during the 2002 cruise). There were also no
encounters with thresher sharks or giant bluefin tuna; however, a large monkfish
(also known as angler or goosefish) estmated at 30 pounds was captured. A single
pollock, a member of the codfish family more commonly found in New England
waters, was also caught. Occasional sightings of humpback and fin whales
surfacing and spouting near the ship added to the thrill of the experience and
aided in breaking the monotony.
A Fish with A Fatal
Attraction
Perhaps
the most exciting event of the whole cruise was the recapture of a striped bass
that was originally tagged by Don Cosden of the DNR Fisheries Service on April
7, 1987, during a gillnet survey on the Choptank River. After 17 years at large,
the streamer portion of the tag had been cut off (if removed by a fishermen, the
capture was never recorded) and only the internal anchor, or "button," remained.
Stephen Taylor of NCDMF, one of the watch leaders, was alerted to the presence
of the button by a telltale scar along the side of the fish near the pectoral
fin. Unfortunately, the fish had to be sacrificed in order to extract the tag
from inside the muscle wall.
We immediately suspected that the tag was quite
old, based on the fact that it had a five-digit tag number (all new tags have a
six-digit number), and was printed with an outdated "301" area code and former
location of the USFWS office. A check of the DNR and USFWS tag databases
confirmed the fish was, in fact, tagged in 1987 (President Reagan was still in
office)! A male, it was only 17 inches long when originally tagged and had grown
to 32 inches by the time it was recaptured on January 20. A 17-inch striped bass
is most likely three to four years old, which means this fish was 20 or 21 years
old when captured. Its relatively small size after such a long period of time
may be explained by the fact that male striped bass tend to have a slower growth
rate and lower maximum size -- a female of similar age may reach 50 inches in
length! This recapture verifies the longevity of striped bass and the distances
they cover while migrating.
The
striped bass tagging data from the cruise is used in a variety of ways.
Recapture data provided by fishermen gives managers important information on
migration patterns, growth rates and survival estimates. The information is also
used to determine general abundance, size and age distributions, length-at-age,
weight-at-age and contribution of hatchery fish, all of which are important
monitoring tools in the ASMFC Striped Bass Management Plan for the entire
Atlantic coast. Recently, the data has been entered into a geographic
information system (GIS) database that will give a better view of travel
patterns and habitat use off the coast of North Carolina, and ultimately help us
maintain viable populations of this important fish.
The tags applied to striped bass during the
North Carolina survey are the same one might encounter here in the Chesapeake
Bay, Maryland coastal bays or along the Ocean City coastline. Anglers catching
tagged fish are asked to call the USFWS at 1-800-448-8322 with the date, the
location, method of capture and whether the fish was kept or released.
Erik Zlokovitz
is a Fisheries Biologist with DNR's Striped Bass Stock Assessment Project.
Photos were provided by Zlokovitz and Roger Rulifson, professor of fisheries
biology at East Carolina University. |