By Shana Miller

It'sthat time of year again. Schools of blue fin tuna

are working their way north through the Mid-At­lantic Bight to their summer feeding grounds.Will New York and New Jersey experience a re­turn of the red-hot fishery for small fish seen in

2005? Will New England see a resurgence of giant bluefin,elusive for the last several years? Or will reports of blue­fin catches be few and far between, as has become all toocommon in recent years?

A team of world-class scientists led by Stanford profes­sor Barbara Block is trying to a.nswerthese and other ques­tions about the status and whereabouts of bluefin tuna.From the Gulf of Mexico to the Gulf of Maine, and Ireland toSpain, they hunt bluefin - not to kill, but to tag. Rather thanyour run-of-the-mill spaghetti tags, they use sophisticatedmicroprocessor-based electronic tags that not only giverelease and recapture locations, but depth, temperature(of both th,e water and the fish's body in some tags), andgeographic location (based on light level) for every day inbetween.

Why all the fuss for a fish? Bluefin tuna are not just an­other fish. They are renowned for their immense size,power, speed and trans-oceanic migrations. They are theultimate sport fish - anglers who have had the privilege to

44 The Fisherman. June 21, 2007

oo

'()'IiI(;11

(;Ijl~'I'

LIGHT SENSOR

fight one on rod and reel will likely treasure the event for alifetime. Bluefin are also the target of a billion-dollar globalfishery. Individual fish sell for tens of thousands of dollars,and in 2001, one 444-pound Pacific bluefin sold for nearly$175,000 atTsukiji Market, Tokyo'sfamed fish auction. Withsuch a high price on their heads,it is not surprising thatbluefin tuna have been severely overfished. Populations inthe western Atlantic have declined by nearly 90 peKeAt,and scientists have predicted that eastern Atlantic bluefinwill go commercially extinct within a few years.

The steep decline of Atlantic bluefin has ensued despitenearly 50 years of international management. Clearly themanagement system is flawed, and Block's tagging re­search (a.k.aTag-A-Giant, or TAG) is gathering informationon bluefin movement patterns, behavior and environmen­tal preferences and scrutinizing the assumptions on whichmanagement is based.The hope is that with better sciencecomes better management.

TAGGING GIANTSFinding bluefin to tag is half the battle when it comes

to TAG research. Over 85 percent of the Atlantic tags havebeen deployed in North Carolina. Eachwinter for 11 of thelast 12 years, the TAG team has hosted a bluefin "tourna-

ment" of sorts. A tournament where

points are based on the number offish transferred to the scientists'tag­ging boat rather than the number onthe scale at the weigh station - a tour­nament where the fish are the realwinners.

Here's how it works. The scientists

ride aboard the "surgery" boats, rec­reational boats chartered or donated

to help with the tagging. Countlessother boats troll the surrounding wa­ters hoping to hook up with a bluefin.The surgery boats also troll, hoping tocatch a fish of their own, but as soonas one of the participating "transfer"boats hooks a bluefin, the surgeryboat reels in its lines, and the excite­ment begins. The transfer boat fightsthe fish to the leader, at which pointthe surgery boat throws their leader(weighted by anything from a tennisball to a rubber ducky) to the boat. Thetransfer boat hooks their leader to the

surgery boat's leader, and it's time forthe scientists to reel in the fish for tag­ging. Once the fish is at the boat, the

\ "lip hooker" meets the tuna throughthe transom door, carefully places ahook through its lower jaw, and slidesthe fish gently onto the deck. Actingquickly to minimize stress to the fish,the 'team measures, tags, and takesa genetic sample before turning thefish and releasing it back through thetransom door. If a pop-up satellite tag(PAT) is deployed, the tag is simplyinserted into the tuna's musculaturenear its second dorsal fin. If an archi­

val tag is deployed, tuna surgery isperformed, inserting the tag into theabdominal cavity through a small in­cision before suturing it back up. Ineither case, the tuna is on the deckless than three minutes in this care­

fully orchestrated process. The entire

maneuver is achallenge in c~m seas,becoming an impressive feat in roughwater.

Commercial fisheries also par­ticipate in the tagging process. TAGscientists charter long line vesselsfor the best chance at catching blue­fin on their Gulf of Mexico spawn­ing grounds. Long line methods arealtered, using fewer hooks (always

. circle) and shorter soak times, tomaximize survival of the fish. Bluefin

are never brought onboard the long

Naturally, the best should be built with the finest components. All plasma rods feature-Fuji SIC (siliconecarbide) concept guide system. SIC is one of the hardest ring guides available and Fuji makes the best.

Graphite reel seats and gimbals are also manufactured by Fuji. Aluminum butts, reel seat and gimbalsare custom made by Stuart. Only high quality cork is used where·applicable. These rods are a natural for

any premium reel. You can fish comfortably using the lightest mono, the heaviest braid or wire line.

Star Rods is the holder of more than 60 IG FA Records.158 Little Nine Drive' Morehead City, NC 28557' For catalogs or customer service call (252) 247-1005

Visit www.starrod.com for Star Rods T-shirts & Stickers.

June 21, 2007 • The Fisherman 45

liners but rather tagged over tbe side; as a result, archiva.1tagging is not an option, and PATtags are used exclusively.Fish have also been tagged with the help of purse seinersin New England and tuna ranching operations in Spain. Inthese cases,fish are tagged in the net or pen before beingreleased with a second lease on life.

To retrieve the data, an archival-tagged fish must berecaptured, and the fisherman must return the tag to Dr.Block for processing. A PAT-taggedfish need not be caught;on a programmed date the tag releasesfrom the fish, floatsto the surface and transmits its data to a satellite, whichthen sends the data to Block's laboratory. Fishermen whoreturn tags are thanked with a $500 to $1,000 reward so beon the lookout for a tag!

A DAY IN THE 'liFE /Since the Tag-A-Giant team rele~sed the first bluefin

tuna with an electronic tag in North Carolina in 1996, near­ly 1,000 tags have been deployed in the Atlantic. The dataacquired is vast (Sixty-thousand days in the life of bluefi-n,with tracks as long as 4.8 years!) and compelling, uncover­ing extensive knowledge about the lives of bluefin, includ­ing seasonal migration patterns, favorite feeding locationsand spawning behavior.

Perhaps most notably, TAGdata yield strong support forthe existence of two discrete populations of bluefin tunain the North Atlantic - a western, which spawns in the Gulfof Mexico, and an eastern, which spawns in the Mediter­ranean Sea.Annual movements of tuna tagged along the:East Coast reveal distinct migratory patterns that vary bypopulation and age class. Adolescent bluefin from bothpopulations travel among similar foraging grounds alongthe EastCoast of North America and in the North Atlantic.

Mature western bluefin follow similar paths up and downthe coast, interrupted by a springtime trip to the Gulf ofMexico, while mature eastern bluefin migrate to the Medi­terranean Seafollowing a variable period of time foragingalong the EastCoast and in the North Atlantic.

Dr. Block's data have shown that a bluefin caught on the'East Coast could have been spawned in the Gulf of Mexicoor the Mediterranean. Unless a tagged fish visits one ofthe known spawning areas while the tag is collecting data,it's impossible to know which population the fish is from.Genetic techniques may help to sort western and easternbluefin as TAG scientists have recently discovered uniqueDNA signatures for the two populations.

Bluefin range widely to feed attheirfavorite dining spots.Tagged bluefin show long residence times in four regions,of the North Atlantic on a seasonal scale.The aggregationsoccur off North Carolina during winter, in the NorthwestAtlantic (Georges Bank, Gulf of Maine and Nova Scotia)during summer and fall, in the central Atlantic (North WestCorner) during spring to summer, and in the East Atlantic(off Portugal) during spring and fall. These "hotspots" arelikely linked to areas of abundant prey and are believedto represent critical foraging habitat. Atlantic bluefin donot appear to be very limited by water temperature dur­ing their travels - tagged fish experienced waters from justabove freezing to 88 degrees.

STMRA.RO, NNE,G,. rS

COMMUNITY COLLEGE

KINGSBOROUGH

Apply Now For Sept. ·07 or Mar. ·08 Admission

, To.Apply Contact:Ms. Danielle Russo

Office of Maritime TechnologyKingsborough Community CollegeSheepshead Bay, NY 11235-2398

• Recent graduate-s employed as Captains and Mates

aboard NY Harbor ferries, dinner and tug boats

• Jobs, ashor.e include Marina Managers and retail sales• USCG approved program leading to Captain's License

• Receive complete USCG required STeW certification

• Training includes 50% on the water, 50% classroom

~Program i~c1udes courses in 'Navigiltiort, S~amanship,Ship,Handling, Vessel Mainteflance, Engine Repair,

Marine Safety, Marine Electronics, Marina Operations

A College ofThe City University of New York

Da n ielle. ru sso@kingsborough.eduwww.kingsborough.edu

.Pursuit 230 Center

"lIome of Super Service"Mattituck Southampton

631-298-4770 631-283-6736

StrongsMarine. com

Your wish came true! Pursuit now offers an entrysize boat with the same fishability of a 3D',

Available without a T-top for the Fly Fisherman

Guaranteed 5 Day In-Season Service ~ All of L./.!

Packs Big Boat Features into 23' of Fun!

46 The Fisherman. June 21, 2007

\.. ..i-'-...•~

/

fisheries, and eastern fish feeding inwestern waters are artificially inflat­ing estimates of the western stocksize. Current management is basedon mixing rates less than 5 percent;TAG data suggest mixing is closer to20 to 30 percent, and managementshould be revised accordingly. Man­agers should also take precautionsto prevent targeted fishing pressureon bluefin when they're in large ag­gregations at the identified feedinghotspots.

Data related to spawning in theGulf of Mexico are among the most intriguing TAG find­ings. Spawning appears to occur in cyclonic eddies and isfocused in the northwestern Gulf to the west of the warmloop current.

Oscillatory diving at night is a likely signal of spawning

behavior, as the bluefin mew be diving to cool down dur­ing some sort of surfaceAilating ritual. Although targetedbluefin fishing has been prohibited in the Gulf since 1982,bluefin are vulnerable to high bycatch mortality on longlines targeting yellowfin tuna and swordfish because thewarm surface waters in the Gulf are low in oxygen andstressful to giant bluefin.

With information on the location and timing of spawn­ing provided by the tags, a discrete time-area closure-couldbe designed to protect bluefin during the critical repro­ductive period.

TOWARD BETTER MANAGEMENTInformation gleaned from Tag-A-Giant research has the

potential to greatly influence and improve fisheries man­agement for bluefin tuna, and TAG scientists are workingclosely with members of the management community toencourage consideration of the best available science whendeveloping regulations. As Atlantic bluefin populationscontinue to decline, it is clear that a change is in order.

Regulations for bluefin tuna assume separate easternand western populations in the Atlantic, divided by an in­visible line at the 45-degree west meridian. Yet TAG dataillustrate that while the populations do indeed sort to sep­arate spawning grounds in the Gulf of Mexico and Medi­terranean, there is extensive mixing of the populationson North Atlantic foraging grounds. As a result, the moreseverely depleted western fish are vulnerable to eastern

48 The Fisherman • June 21,2007

'06 18 Dauntless

135 hp Verado

'~~fi~1~

'06 285 ConquestT-225 hp Verados

~~ o:J) ':?l r.: "'tlJi?

'06 21 Ventura

225 hp Verado

SURFSIDE 3

'07 18 Ventura

150 hp Verado

(1<:''-J

WliALER -;r D EA LS

'06 270 OutrageT-225 hp Verados

$<:'

'06 17 Montauk

90 hp 4-strokew/trailer

';?

':':-.

:•.•1I ••

The Foundation's goal is to support scientific research,policy and conservation initiatives that promote a sustain­able future for bluefin tuna.

If you have experienced the scream of a reel after hook­ing a bluefin, if you've felt their strength at the other endof the line, or if you're simply captivated by this remarkable

species - please join us. The next five years are critical tothe future of northern bluefin tuna, and we ask for yoursupport in our efforts to help steer bluefin onto the roadto recovery.

Visit us at www.tagagiant.org or call us at 631-539-0624or toll-free at 866-533-3580 to make a donation and learnmore.

Last year marked the fourth straight season where u.s.fishermen could not catch their quota, despite repeatedacts by the government to relax regulations. Is it becausebluefin are feeding in different places?Or are there so fewfish left that we can't catch them? Only time - and tagging- will tell. t/

i.f.

:.u.:

IIIITIT~'iII'mI:{j"'II~

1I.;1In

r:I'im'i!iI~~mr:r.u• WAC. 20% down, 12 yr. at 9.5% APR. and indudes all factory and finance rebates. Taxes and title fees additional.i Offer ends 5/31/2007. See dealer for complete details.

June 21, 2007 • TheFisherman 49

AMERICA'S #1 BOATING RESOURCE • 88 LOCATIONS NATIONWIDE. ALWAYS OPEN AT MARINEMAX.COM

In addition, tagged fish that travel to the Gulf of Mexicotend to be very large, 94 inches curved fork length andabove on average.This suggests that western bluefin spawnfor the first time at a mean age of 12, rather than 8 yearsold, the current spawning age used in assessments.Thisdiscrepancy could be contributing to the lack of rebuildingdespite projections for an increase in the population.

New tagging data come in every day, confirming whatwe've already learned and revealing new insights into thesecrets of bluefin. Now is the time to incorporate the vastknowledge acquired over the last decade of electronictagging into management. Bluefin tuna are too valuable- both to the economy and the open ocean ecosystem - tolet the current declines continue.

Concerned by the plight of Atlantic bluefin tuna, andarmed with the scientific data to improve management,Dr. Block teamed with a dedicated group of recreationalfishermen and other scientists to launch the Tag-A-GiantFoundation in 2006.