The bluefin tuna, one of the largest species of bony fish in the
world, is renowned for its size, speed and beauty in both the
Atlantic and Pacific Oceans. The known range of the Atlantic bluefin
tuna is from Newfoundland to Brazil in the western Atlantic and
Norway to central Africa in the east Atlantic. The bluefin attracts
intense interest in numerous recreational and commercial fisheries.
Bluefin tuna is prized in Asian markets as one of the best fish
to eat raw. Its seasonal feeding migration to the Gulf of Maine
has become a traditional feature to New England fishing ports.
Over seas, feeding and spawning migrations in the Mediterranean
and in the Pacific have attracted fisheries for centuries, and
resulted in cultural reverence for this giant fish.
Similar to other members of the mackerel family, bluefin tuna
has a graceful, streamline appearance. The snout is pointed and
the tail region is slender, both leading up to a robust body,
hence providing for the "football" name often given
to juvenile bluefin. All fins appear streamlined and the dorsal,
pelvic and pectoral fins fit into slots in the body to reduce
drag. A series of small, yellowish finlets occur from the second
dorsal and anal fin to the caudal fin. Bluefin tuna are darkly
colored on their dorsal surface with dark, shiny blue tones that
can approach black. The dark coloration fades and becomes silvery
towards the lateral line. Below the lateral line and the belly
are silvery and may have irregular bands and spots that are iridescent
white, gray and silver. Dorsal fins are dusky to black and ventral
fins are dusky with lighter shades of white, gray, and silver.
Because of their large size, it is usually not a problem distinguishing
bluefin tuna from other tuna species off the coast of Massachusetts.
Other than large size, bluefin can be separated from other Thunnus
species by their higher gill raker count (34-43), shorter pectoral
fin, and presence of striations on their liver.
Bluefin tuna are a fast-growing species that can exceed 10 ft
in length and weigh over 1,000 pounds. The largest bluefin tuna
caught by an angler in Massachusetts waters weighed 1,228 pounds
in 1984, and the all-tackle record for the Atlantic is 1,496 lbs.
caught in Nova Scotia in 1979. One-year-old bluefin tuna are about
10 pounds by mid-summer and are a sporadic visitor to our shores
south of Cape Cod. Ages 2-4 are typically 20-80 pounds and an
annual visitor to feeding grounds south of Cape Cod. Until recently,
these school tuna were not considered common visitors to the Gulf
of Maine, although they were found in high abundance in the Gulf
of Maine during the 1940s and 1950s and observations have increased
since the 1990s. There is substantial variation to individual
growth once bluefin reach five or six years. Giant tuna is a subjective
term used for mature bluefin seen in the Gulf of Maine that typically
are at least 10 years old and about 300 pounds or higher.
The bluefin's large size and capacity to visit all the temperate
oceans of the world have made it a difficult species to study.
There is much we still don't know about bluefin tuna.
Physically, they have the ability to retain metabolic heat, rendering
them the closest thing to a warm-blooded fish. Being warmer than
the surrounding water allows them conduct physiological processes
faster than cold-blooded fish. Food digestion and oxygen transport
can occur quicker and more efficiently. And the warmer bluefin
can colonize colder regions of the Atlantic in search of prey.
Their ability to stay warm in cool water brings them to the Gulf
of Maine each year on a feeding migration. They typically arrive
in June and depart in October. They will aggregate and forage
on concentrations of small pelagic prey like mackerel, sand lance,
sea herring, menhaden and squid. In the absence of large schools
of pelagic prey, they will feed on whatever they encounter throughout
the water column. Bluefin are a schooling species that usually
remain in schools of similar sized cohorts. Jeffreys Ledge, Stellwagen
Bank, Cape Cod Bay and the Great South Channel are traditional
fishing grounds for giant bluefin. However, movements in the Gulf
of Maine and south of Cape Cod are highly variable within each
season and year-to-year and certainly depend on forage concentrations.
The movements and spawning habits of bluefin tuna still contain
some mystery. Spawning is known to occur in the western Atlantic
primarily in the Gulf of Mexico and within the Mediterranean Sea
over in the eastern Atlantic. We have long known that many bluefin
that spawn in the spring in the Gulf of Mexico will head north
to feeding grounds along the U.S. continental shelf. There is
a growing body of evidence that indicates western Atlantic bluefin
tuna can interact with the spawning and feeding grounds in the
eastern Atlantic and Mediterranean Sea. Despite being the same
species, the expected age of first spawning is quite different
for the two groups of tuna. Western bluefin are thought to mature
at about age-8 when they weigh near 250 pounds. Eastern bluefin
mature at about age-4 when they weigh less than 80 lbs. Hopefully,
ongoing research on reproduction, migrations and stock identification
will shed more light on the Atlantic stock composition of bluefin
The harvest and management of bluefin tuna in the western
Atlantic has occurred for less than 100 years, unlike the rich
history found in the eastern Atlantic and Mediterranean Sea. Bluefin
tuna were not an important target species on the East Coast of
the United States during the first half of the 20th century. Most
commercial landings came from handgear catches in Maine and trap
net catches in Massachusetts. The latter half of the 20th century
saw major technical changes to bluefin tuna fisheries that resulted
in stock reductions and prompted extensive management measures.
Three major developments have had the greatest impact on bluefin
tuna in the Atlantic: development of purse seine fishing in the
late 1950s, development of high-seas longlining by the Japanese
in the late 1950s, and the opening of the high-price Japanese
sashimi market in the 1970s.
Concerns over the health of Atlantic bluefin populations in the
1960s and 1970s resulted in domestic and international management
efforts. The commonwealth of Massachusetts enacted the first bluefin
tuna regulations in the United States in 1974 in order to protect
bluefin tuna in Cape Cod Bay. In 1975, the International Commission
for the Conservation of Atlantic Tunas (ICCAT) enacted its first
restrictions on Atlantic Tuna and the U.S. Congress passed the
Atlantic Tuna Convention Act to authorize the Department of Commerce
(through the National Marine Fisheries Service) to implement ICCAT
regulations. In 1982, ICCAT separated Atlantic bluefin tuna into
western and eastern Atlantic management stocks based on the assumption
of separate spawning grounds and negligible movements between
stocks. This management regime is still in place and outstanding
questions over stock identification and allocation have been controversial
for 20 years. Numerous countries now share an eastern Atlantic
quota that is comparable to historical high landings. The U.S.,
Canada, and Japan share a quota for the western Atlantic that
is modest relative to historical high landings. There is growing
evidence from high-technology tagging and stock identification
methods that suggests there is substantial interaction between
the stocks. This information, along with allocation disagreements,
and increasing fishing pressure on the high seas by longliners
fishing in violation of ICCAT rules have created a very difficult
Presently, the western fishery is highly regulated and is operating
under a rebuilding plan that seeks to return the population to
maximum sustainable yield. The U.S. receives approximately half
the western quota, and NMFS allocates this amount among the following
six fishery categories:
1. Purse Seine Category (limited to 5 vessels)
2. Harpoon Category
3. General Category (handgear effort with hook and line and
4. Angling Category (recreational hook and line only)
5. Longline Category (incidental catch by limited number of
6. Trap Category (small quota for trap nets)
Participation in these fisheries requires permits issued by the
National Marine Fisheries Service (NMFS). Contact NMFS for permit,
quota allocations and regulations at http://www.nmfspermits.com
or (888)-872-8862. Commercial sale in the General Category is
currently limited to bluefin tuna 73 inches or greater. The minimum
size for bluefin tuna retained in the Angling Category is 27 inches.
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Recreational Fishery Regulations
Both the recreational and commercial fisheries for bluefin tuna
are regulated by the National Marine Fisheries Service (NMFS).
Click here for more
information, or call 1-888-USA-TUNA.
Angling and Handling
Bluefin tuna are one of the greatest challenges to anglers
off the coast of New England, and Massachusetts continues to
be a center of activity for giant bluefin tuna. Massachusetts
has been the top state for commercial landings nearly every
year since the late 1940s. The port of Gloucester has been the
top handgear port for bluefin tuna on the East Coast during
most of the last 50 years and recently Harwich has taken the
lead on the graces of high catch rates in the Great South Channel.
More than any other fish, the lines between commercial
and recreational fishing are blurred when it comes to bluefin
tuna. Most giant tuna are sold because of their high value.
Yet, many otherwise sportfishermen participate in the commercial
end of the fishery, and the saltiest commercial fisherman continues
to be thrilled with each hook-up.
Catching giants by rod and reel requires the largest of high
quality reels spooled often with 200 lbs. test line. The two
primary methods are trolling with rigged natural baits or artificial
squids on spreader bars and bait fishing on anchor with live
baits or chunks of local prey such as herring or mackerel. The
movements of bluefin are highly variable and there are numerous
ways to lose a hooked giant. Therefore, catch rates are typically
low in this fishery. This fact does not diminish the enthusiasm
shown among anglers. The expenditures by thousands of hopeful
anglers pursuing bluefin tuna in Massachusetts is an economic
force in itself.
Smaller bluefin tuna are fished in similar patterns
as the giants, with a downsizing of rod and reel size and line
strength to match the target. Anglers south of Cape Cod will
often increase the troll speed and use a variety of brightly
colored, single hook lures to attract school tuna that can be
found among tropical tunas and marlins that can also visit the
continental shelf off Martha's Vineyard during the summer.
Take care to bleed and chill your catch quickly. The giants
require specific attention to meet their potential value in
the Japanese sashimi market. Lift the pectoral fins on both
sides and make a one inch incision to cut the cutaneous veins
and arteries the run along the lateral line. Tuna should be
carefully gutted also soon after capture. The bright red flesh
is excellent on the grill after marinating in your favorite
concoction. Be sure not to over cook and dry out the flesh.
Bluefin is even better eaten raw using wasabi and soy to garnish
and spice the ancient ritual.
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Commercial Fishery Regulations
Both the recreational and commercial fisheries for bluefin tuna
are regulated by the National Marine Fisheries Service. Click
here for more information,
or call 1-888-USA-TUNA.