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Bluefin Tuna Information
Everything you need to know about the giant of tunas.
Sources for more information: For more on the history of big game and big tuna fishing, check out Fin-Nor, The Legacy Years, a new hardcover book full of classic photos, published by Zebco, 2007. www.bigmarinefish.com. Jim Chambers’ website devoted to big game fishing and conservation.  Mather, F.J. III, Mason, J.M., Jr., and A.C. Jones. 1995. Historical Document: Life history and fisheries of Atlantic bluefin tuna. NOAA tech. memorandum NMFS-SEFSC-370; 165 pp. Available from NMFS. Links to other stories about bluefin by FS: www.floridasportsman.com/casts/040507/ In your library, also track down these three classic articles by Vic Dunaway about the Bahamas bluefin fishery in issues of FS in May ‘96, June ‘96 and April ’72. The Suit to Stop Bluefin Bycatch In 2005, the World Wildlife Fund, the Blue Ocean Institute and a host of other fisheries advocates filed a petition with NOAA to stop longlining in the Gulf of Mexico at bluefin tuna breeding sites during their spawn. The rejection of that petition has prompted Carl Safina, the Blue Ocean Institute and Earthjustice to file a lawsuit against the Department of Commerce and NOAA. Lead lawyers for the case, Steve Roady and Jennifer Chavez of the Earthjustice Foundation in D.C., filed a request for summary judgment to halt longline fishing this spring in the Gulf by order of the federal Government. The request, filed November 19, 2007, also calls for a federal “environmental analysis to accompany new long-term management measures for the longline fishery in the Gulf of Mexico designed to protect spawning bluefin tuna.” The suit names the Department of Commerce, which oversees NOAA Fisheries, which manages and controls fishing in federal waters. The Memorandum of the Plaintiffs, filed by Roady and Chavez November 19, 2007, states: “Fishing pressure on bluefin is now at its highest point ever, while the bluefin population is at the lowest recorded level in its history.” In addition, “This case presents perhaps the last best chance to save one of the most valued big fish species that lives in United States ocean waters—the western Atlantic bluefin tuna—from population collapse and commercial extinction.” The defendants in the case are Carlos M. Gutierrez, the Secretary of Commerce, and the National Marine Fisheries Service, or NMFS, which, by law, is charged to protect and revitalize U.S. waters and fisheries by order and act of Congress through the Magnuson-Stevens Act, first made law in ’76, and recently reauthorized in January 2007 by President Bush. The Magnuson-Stevens Act, and the Atlantic Tunas Convention Act (ATCA) a federal statute, authorize NMFS to manage tuna in accord with quotas set by the International Commission for the Conservation of Atlantic Tunas, or ICCAT. The suit alleges there is a de facto fishery for bluefin in the Gulf of Mexico. Here, current regulations allow a longliner to retain three giant bluefin on a single trip, what might be worth more than $50,000 at current prices, as long as other catch requirements are met. That’s serious incentive. That the U.S. commercial fleet cannot meet its bluefin quota set by ICCAT, and at the same time, the U.S. commercial fleet right now is catching and discarding dead, giant spawning bluefin tuna at their spawning grounds in the Gulf, and has been doing so for decades, is a paradox beyond comprehension. Mark Stevens, of the World Wildlife Federation, one of the signors of the 2005 petition, says his organization is calling for a moratorium on all directed bluefin tuna fishing, commercial and recreational. “We have to listen to the advice that the scientists are giving,” Stevens says. “They’re not in the eastern Atlantic, and you can see the results of that mistake over there, and their fishing continues to harm stocks of our fish. We want this to be a break from fishing, not the end of fishing. We want long term sustainable fisheries. Let the scientific community put together a plan to manage the fish and support it. It’s painful, but there are cases of fish making comebacks with proper and enforced management. You can have the pain now or the pain later,” Stevens asserts, “and the pain later is greater.” The suit charges NMFS with failing to rely on the best scientific evidence available, in the agency's rejection of the 2005 proposal to control longlining at bluefin spawning sites. The agency's contention at the time was closing certain areas might redistribute effort elsewhere. That reasoning, the suit contends, has insufficient evidence to support it, and in fact evidence exists to contradict that assumption. Furthermore, the Magnuson Stevens Act requires that fisheries avoid or minimize bycatch mortality to the extent practicable. Conservationists and scientists involved with the suit commonly point to a second paradox: The U.S. federal government protests overfishing in the eastern Atlantic, including both high quotas and illegal fishing practices like the use of spotter planes to find schools of bluefin, but won’t stop the longlining in the Gulf. “The federal government has been critical of the European Union’s treatment of bluefin tuna,” says Steve Roady, Earthjustic lawyer on the case, “but we have our own Western Atlantic stock that our government has the power to protect with the stroke of a pen, and they are not doing it.” William Hogarth, former head of NOAA fisheries (now dean of the School of Marine Sciences at the University of Southern Florida), lobbied hard for a moratorium on bluefin fishing in the eastern Atlantic at the most recent ICCAT meeting in November. Of the longlining in the Gulf, Hogarth says, “We have always followed scientists' advice. Myself and others at NOAA made those decisions that are in place regarding fishing in the Gulf, and we based them on the best scientific advice overall that we could gather. We were concerned that to close the spawning areas would only cause longline vessels to shift their efforts to other areas and perhaps other species, and place extra pressure on those populations, which we did not want to happen. We felt very comfortable that the number of bluefin taken incidentally would not do great damage to the stocks overall. “NOAA is also trying to develop new gear," Hogarth continues, "like a breakaway hook, that will give way if a bluefin or other bycatch species that is bigger than the target species, often yellowfin, gets hooked. And I assure you, if there are hotspots of high spawning activity in the Gulf identified by Barbara Block’s research, then government fisheries managers will look at that data. In the end, we may all have to take more drastic measures to ensure the survival of this species.” The District Court Judge in D.C. is expected to agree or reject Earthjustice’s request for summary judgment some time in April. The court’s summary judgment could order the federal government to change current longlining practices in the Gulf.
Bluefin on the Menu? If you’d ever like a chance to catch a bluefin on your own, you probably won’t want to support the commercial market for bluefin at shops and at restaurants. Suppliers on both sides of the Atlantic and in the Pacific are currently on the verge of wiping out bluefin schools. As popular as bluefin is in Japan, we can’t completely lay the blame on that nation alone. Plenty of U.S. restaurants also push bluefin, and back in ’06, baby bluefin also began showing up on some fancier restaurants’ menus. This spring, according to the New York Times, supermarket chains in Europe have started to ban sales of bluefin due to the crisis, and that tactic may spread to the U.S. If you want to learn how to make sushi yourself with the fresh fish you catch, check out www.mahalo.com/How_to_Make_Sushi. As if all that’s not enough motivation to lay off commercially caught bluefin, keep in mind that older, bigger bluefin contain among the highest counts of methylmercury of all pelagics, according to a spate of recent studies. The Environmental Protection Agency warns us that methylmercury is a neurotoxin that accumulates in our blood and tissues and poses some serious health threats to those humans with high counts of the stuff. For more, check GotMercury.org. For a list of recommended commercially-harvested species, look at www.mbayaq.org/cr/seafoodwatch.asp, Monterey Bay Aquarium’s Seafood Watch website.
Interviews with authorities, conducted Dec. 20, ’07, through Feb. 20, ’08.
Capt. Alex Adler Adler first fished at Cat Cay in 1980. He still fishes bluefin, but the schools are not quite as big. The weather patterns have really changed. The trade winds were ESE, during years 80-87, and weather would settle into the East Southeast, and he could fish every day. Now, not only are the schools not as big, but the weather no longer settles into that pattern. Now you might only get 4, 5, 8 days out of 40 that are right. We used to be able to go fish for marlin when the bluefin slacked off over there, but the longliners in the Straits hurt them so bad that stopped. Now, though, they may be coming back since the longlining stopped, up until recently when they got their foot in the door again with research longlining. What I’m seeing by eyes, schools are smaller, I remember seeing thousands of fish in a day. They’ve punished that fishery in the GOM. Adler refers to the public, common knowledge of the damage caused to bluefin stocks by long liners in the Gulf. In the early 80 and early 90s, literally thousands of fish, big spawing bluefin, died and were cut off long lines. The longliners pursuing yellowfin and swordfish could not take or sell the bluefin, so they wasted them. How does the Bahama bluefin fishing go? Boat’s pointing south, 40 to 300 feet to scanning, depending on the wind along the reef, I’m scanning, scanning, they’re a non-feeding fish. You have to trick them into biting with bait position. These are lean, migrating fish, trick them with bait position. If they’re spread out I’ll use the wake of the boat to bunch them up and herd them like cattle. They’ll ride the wake like porpoise and you’ll get the bait in front of them and then their sense of competition kicks in and they go for the bait, a complete instinct strike, angry and strong, not a feeding reaction. Late July, and in August here in Islamorada we do catch these baby bluefin, mixed in with small blackfin and skipjack, off Islamorada. And that is, precisely, where they should be, and the size they should be, according to Dr. Graves, who studies the young fish. A big bluefin, it’s like hooking a freight train. A moving vehicle. Now you’ve turned the boat, and you’re moving north with the school, hook them, run across the surface, trying to stay with the school, or else they’ll go screaming into the blue. You’ve got race the boat due west and beat them off the edge off the sheer wall. Boat outside the wall otherwise they will cut you off at the edge as they go off the edge and down, the way the sea floor drops off there like the edge of a tabletop. It takes a quick reaction for the skipper with a keen sense of where the line is, with a big belly in the line after making the turn, even as the line is slicing through the water, torn away by the fish, and you’re roaring ahead to beat the fish to the edge. It’s exhilarating and beautiful. You’ll sit there and there won’t be any and the wind will get right. All a sight fishery. There’s got to be a way to catch them without seeing them. Also lately big bluefin have been caught in the Abacos. Hooked up in April May June, Abaco trench. One day in June, July, a couple of guys fishing for swords on the bottom here in Islamorada said they got spooled so fast, they’ve never seen anything like it. That could’ve been a bluefin leaving the Gulf, Adler says. It’s possible, or they could’ve hooked the bottom. Florida Swordfishermen may find out this summer. Unless you’re using 130s and ready for the fight of your life, be prepared to cut your line. 4 years ago, 2 big bluefin one day, one the next day, Cat Cay. Fished with Johnny Morris, started on Kalex in 80 and we fished 26 tuna seasons together won the Cat Cay tournament twice, on the Tracker, a 42 foot Rybovich, and a 61 Jim Smith, caught them up to 900 pounds, and we let ‘em go, largest ever caught by John Morris was 1100 pounds and released, Bobby Jones released 1050 to 1100. Mark Stevens First, can you tell me any latest developments in the efforts to protect bluefin tuna stocks and their breeding grounds in the GOM? There’s the Earthjustice lawsuit to impose time and area closures on spawning areas. We’ve also become involved in the Eastern Atlantic bluefin tuna fisheries. Everything has just kind of fallen apart in the East. WWF called for a moratorium until a rebuilding plan is put into place, based on ICCAT’s scientists’ recommendation. We did join with other organizations PEW, environmental group expressing our concern to Hogarth. The problem is the fishing states and the consuming states. The European community and Japan. The population in Western Atlantic is in even bigger trouble than in the east. We’ve reduced the total allowable catch here in the Western Atlantic, but they’re still not coming back. We’re now pushing for an Atlantic-wide moratorium. No fishing in the western Atlantic for bluefin tuna. Look at striped bass in the mid-Atlantic, the way that fishery has come back. Anglers might have to bite the bullet, as they did with fishing for striped bass, but that sacrifice paid off in a restored fishery that they now enjoy. We hope that might happen with bluefin tuna as well. Regarding the bluefin fishery around Bimini, which declined in the 60s and 70s, do you have any idea of who depleted that fishery? No, I can’t say that I do. I’m not sure what authorities would say. But we all need to listen to the advice that the scientists are giving. In the Eastern Atlantic, that’s the mistake that they’re making. Fishing nations and consuming nations say no to accepting reductions in their allowable catch, and they approve a catch that is double their scientists’ recommendations. What the sportsmen can do is a tougher question. It’s the big guys that are the worst offenders, but what the sportsmen can do is support a moratorium. We want this to be a break from fishing, not the end of fishing. We want long term sustainable fisheries. Let the scientific community put together a plan and support it and that would be helpful. It’s painful but there is evidence that this works. You can have the pain now or the pain later, and the pain later is greater. There is a split among sportfishermen. It’s a mixed perception. The bluefin seem to come and go in different areas and whenever the bluefin disappear from an area and don’t return, or don’t return in their previous numbers, say, around Florida, you’ll get more support for a moratorium. To most recreational and professional charter fishermen, ICCAT is considered a joke. But it’s really not very funny. In the bluefin industry, there are not only the difficulties of orchestrating a consensus among nations, but there are the forces of very big business at work in the bluefin fishing industry, as well as other forces of organized crime and other forms of corruption. These are very difficult forces for any organization to manage, the prevailing culture and direction of ICCAT aside. Jim Chambers, former NOAA biologist, now seafood purveyor and defender of big game. See www.bigmarinefish.com, with the “Kill-O-Meter,” the display of the moon phase which reflects the rate of killing by long lines, which increases with the fullness of the moon. Also: www.primeseafood.com After the 2005 petition was filed, NMFS let it be known that they weren’t going to do anything to protect bluefin tuna until the species’ stocks were down to 1 percent of their original population figures. That’s pre-1960, pre-big time commercial fishing for them, numbers. Well, we’re getting down to that level now,” says Jim Chambers, a big game angler himself and federal fisheries biologist with NOAA for more than twenty years. Stock figures vary, but most sources report that stocks of Western Atlantic Bluefin tuna are down 90 to 97 percent from 1970. Story excerpt: Western Atlantic bluefin, “our” stock, have not been subject to thousands of years of fishing pressure as those in the Meditterenean have, and they reach sexual maturity at a later age, perhaps as old as ten years old. Generally, science puts their sexual maturity at between eight and twelve years, and they live as long as fifty years. The Eastern Atlantic tuna have adapted to the pressure on them by reaching sexual development at an earlier age and therefore replenishing their populations better. The consequence is that the current generation of giant Western Atlantic bluefin is only the second to come under intense fishing pressure, or as Dr. Barbara Block says, “All the damage has been done to the stocks within my lifetime.” Chambers and his colleagues, many of them co-signors of the original 2005 petition to the Department of Commerce to protect spawning bluefin in the Gulf, are now petitioning the Department of Commerce to have bluefin listed as a Threatened or Endangered Species with NMFS and the Federal government. “If stocks aren’t already low enough to be listed as Threatened, they will be soon enough,” Chambers says. “It’s only a matter of time.” Dr. Molly Lutcavage, Ph.D. How are you researching bluefin tuna and their migrations? What we have is Tag a Tiny project. When we first started, we only implanted archival tags. Now we’ve had 3 fish recovered out of 127 implanted, 27-29 inches, tagged off VA or Cape Cod, 3 recaptures, 2 confirmed. Angler believes he lost a fish in January that he had tagged in July. He thinks that he has intercepted them on several occasions. Off New Jersey. Famous recreational angler, authority on bluefin, Cookie Murray, Cookie II. Now we also use miniature pop-up tags, 32 or 36 tags, deployed out of Cape Cod, on fish tagged in summer, and they travel down to Hatteras in January not far from giant bluefin. What we don’t know is where they are in between. Tags give depth and temp every 15 minutes, and location. Also, what’s interesting, one of the first purse seiners, Frank Skinowski, out of Fair Haven, MA., back when they were allowed to purse seine, he saw two distinct size classes, which didn’t make sense if they all spawn at same time in same place. Catch them off Virginia. Studies by Japanese have shown baby bluefin capable of swimming very quickly and highly. Tag A Tiny.com We’ve found the same story since 1997, fully mature size classes about a third of fish go into the Gulf, some go to Spain, some linger into Caribbean, by the Bahamas. We’ve said all along that numbers of fish are not going to the GOM. Not spawning every year or are they spawning elsewhere? These are really big fish and I still think about what the old timers said, that they may be spawning elsewhere, maybe in the Bahamas. These fish stayed on east side of Gulf Stream and then went back where they where tagged near Nova Scotia. Never went into the GOM. We have studies that show that by histological evidence fish that are mature and spawning. Histological status establishes that fish 73 inch fish are sexually mature when they get here in the northern waters and you couldn’t find their follicles if the fish have spawned far away. There has long been conjecture that bluefin might be spawning on the edge of the Gulf Stream, way back from Frank Mathers. If bluefin don’t get anything to eat within two or three days they die. Not all locations may be adequate for sustaining these fish The big thing is that we lost the giants, and we’re also seeing huge changes in the young populations, moving north. Global warming is affecting the oceanographics, and I think that we’re seeing the effects of that in the populations’ movements. Recreational fishermen are the future for research. How else will we get to these fish? Bob Cowan, Ph.D. The larval stages: Florida Straits focus, billfish larvae, other scombrids, just to give you a clue, in 2 years 2003 and 2004 sampling every month all the way across Straits of Florida, several hundred thousand larvae of all fish, reef and pelagics, only caught 2 bluefin larvae. For comparison’s sake, when we’re close to a sailfish spawning site, we have hundreds of sailfish larvae in a single net. More likely that those one or two larvae have been carried from somewhere else. From those samplings and subsequent samplings, we can conclude that bluefin are not likely to be spawing in the Straits, though we are also currently comparing our counts with samples taken in the 70s and 80s to get a statistical indicator of the decline of the prevalence of bluefin larvae. There is speculation that the bluefin may be moving their GOM spawning grounds more to the west, and that repositioning would, due to currents, make it unlikely that their larvae would be carried out into the Straits of Florida. That is one explanation for the drop in larvae counts that we’ve seen. Another is that the population of bluefin itself is simply dropping. Once we get an idea of the historical trends over the decades, then we have a better chance of saying whether or not bluefin are moving and where. There’s really hardly anything known about baby bluefin. Half a meter long they are rare they are hard to catch . That’s why we go after larvae. They’re relatively abundant and easier to catch. There’s an indication, highly speculative, that the population in the GOM is either making that shift farther to the west, so that their young are not easily carried out the Straits of Florida or that they’re going down in numbers. There is also an indication that the GOM population may be discreet from the Northwestern stocks, where they are still catching the giant bluefin. These stocks may have separate spawning grounds, but all this is still in the investigative stages. It’s important to state that some of this is speculation. We aren’t catching the larvae in the Straits. Get an idea of the historical trends then we have a better chance of saying whether or not bluefin are moving and where. Richards has collections from the 70s. I’m sure that there has been a noiticeable drop since the 70s or 80s. Brad McHale 2007 report: once those numbers are finalized, where did we end up in landings, we ask. We’ll look to the previous year and look at the bag limits and we may amend the bag limits and we do that retroactively to plan for the next season. Anglers need to keep in contact with changing regulations. Website. www.hmspermits.gov to buy and follow updated regulations. Check before you go. Bluefin tuna in general has gotten a lot of press. McHale is an avid recreational fishermen himself. For management purposes 27 to less than 47 inches, curved fork length measurement, 15/20 pounds 60/65 pounds at these lengths. Historically, key component from recreational fishery from Virginia Beach, through Cape May, Maryland, and New York and Mid-Atlantic states, even going back ten, fifteen years. One thing that we’ve noticed over the last five years is an increased presence of school coming to the Gulf of Maine and a decrease in the fish off the Mid-Atlantic states, off Cape Cod, Gloucester. They’ve been available for an extended period of time now. From a management perspective, we need to be concerned with our catches. Are they line shy, or feeding, can the boats reach them, and what do we have our rec. limit set at? All these variables really affect the rec. catch? We manage bluefin tuna typically by weight, by metric tons, and comm.. and rec. sector each has a certain percentage of the pie. For 2005, 119 metric tons on small bluefin school, comm.. fishermen are not allowed to land fish less than 73 inches. Commercial quota was at 930 metric tons. Breakdown: 8500 small = 119 metric tons. Individual large fish, 4500 to equal the 930 metric tons. One thing that we’ve noticed is that over time out of all the vessels getting permits, the one segment that tends to grow is the rec. sector. One signal that we get out of the program that generates the estimates, in the surveys, we get info that bluefin are increasing as a targeted species. Currently we do not have estimates of what goes unreported by rec. anglers. Large pelagic survey mako, wahoo, etc. we also have a census program in N.C. and Maryland. Two conflicting perspectives, may time over change, lot of signals pertaining to bluefin that the stocks are in trouble. When it comes to rec. anglers, two concepts that we struggle with. I only take one fish, what impact compared to commercial? What gets lost is that there are potentially 25,000 people like me and cumulative impact. Also, the mentality permeates that if I report my fish to the agency, that’s one fish closer to having the fishery closed. Think about your kids. With any natural resource as stewards, anglers or managers, if we don’t have that long-term vision see the bigger picture of your actions today… Enormous importance of catch and release. We need to definitely address the darker underside. Not in our interests to circumvent the reporting process. Huge biological implications of not reporting fish that are landed. Two signals that can come out are that they are not there and we might have a collapse. Or if we knew that there was an abundance that may sway fisheries management another way. They do not encounter the school bluefin tuna often in the Gulf, and it’s rare that we hear about school size being caught there. We do not allow vessels to go out and target bluefin in the Gulf. WE do allow a rec or charter who happens to hook into a trophy bluefin to retain one per year. On average those trophy fish numbers tend to be relatively low, for a couple reasons. You need to have gear to have any shot to land those fish. 50 wides and 80 wides and if you aren’t really skilled, and you get a giant, it’s going to break you off or spool you. Where individuals fish, if you’re in for the smaller ones, you’re not likely to encounter. Globally, there’s a steep price tag on each individual fish there’s a lot of incentive to go out and catch that fish. There’s a lot of pressure. Forage, oceanography, non-source pollution, all make a complex environment. We have more questions than answers right we have a long way to go still. Shana Miller Tag a Giant research started by Block in ‘97 with electronic tags to discover migration patterns behaviors and habitat requirements. In 2006, our foundation started research to try to get this info into management to help them manage stocks better. Then we also raise money to support the research. It’s incredibly expensive. The foundation is relatively new. Among the management community there is recently a greater acceptance of tagging work and genetic studies work. The outside data are corroborating our findings, such as studies of tuna’s otoliths. The data indicate that there are two stocks, though they are mixing to feed and they separate to breed. This is important because it shows clearly that what goes on in the Eastern Atlantic affects our fisheries. In the late 90s, 2000, we saw a huge influx of those Eastern fish. That’s why we’ve seen a big decline of our fisheries. It’s important to note that we do have a separate population because it could disappear. If we allow catch levels to be too high, then we could endanger our own stock. Some of our western fish do cross the 45 degree line, the Flemish Cap area, and there they are susceptible to the high catch levels in the central Atlantic, especially by the International Japanese longliners around Flemish Cap area, central north Atlantic. We want to keep that western Atlantic population strong. It’s hard to argue the TAC levels because they’re being limited by the availability of fish. About 14% in 2007 of TAC quota. There is a lot of scientific support for it, so we’re not against it, but we’re not advocating a moratorium on fishing for bluefins. Scientists have estimated that there are as few as 8000 metric tons of adult bluefin (giant, 10 year old fish) in the Western Atlantic. The situation may warrant a moratorium. What is the virgin biomass in 1950, before industrial fishing? We do not know. Look at catch levels, back at 1970s, precipitous decline of commercial catches since the 50s. In the Med, these fish have been fished for 2000 – 3000 years and they are more resilient to fishing. Western Atlantic, more slow-growing, only about 10 centimeters a year. Our western pop hasn’t evolved to withstand heavy fishing pressure. We’re really only in the 2nd generation of bluefin that have been heavily fished. There is a workshop in Spain by ICCAT to look at regional extinctions of bluefin tuna. There was a fishery off Brazil that has been decimated. That Bahamas-Bimini sight fishery for bluefin, probably the most exciting and well-known bluefin fishery in the world, may have been a separate stock, a regional stock of fish, now wiped out, or it may have been part of the stock that existed in Brazil. We simply do not know. These fisheries have changed so drastically in only 50s, the lifespan of some of our scientists working on them. For instance, Canada is still catching fish. But why are they not off the US anymore? The NC fishery has declined precipitously in only the last ten years. In early 2000s, In Jan. 2005 the commercial fishing heavy started, 300 fish, by 2007 down to 103 in Jan. A 66% decline. The great percentage of those fish are from North Carolina. These are adolescent fish on the verge of spawning but they have not quite reached spawning age. You do have some East Atlantic fish there. We’re really trying to find out where the US fish have gone, but we haven’t found any newer locations where they’ve gone. In 2005 small fish up near L.I. and New England. The East Coast of FL is definitely a corridor for bluefin going into the GOM. March April June. They winter and feed up north and zoom down. They get pretty close to the tip of FL and go around the tip and past the Keys into the GOM. Not necessarily doing much feeding, moving pretty quickly through the area. Based on tagging bluefin are off the shelf of the GOM. We know that every fish there is from the Western population and it is there to breed. And those are the most important fish to protect. In a larval stage they’re drifting…In 2007, they caught hardly any bluefin larvae, NOAA does studies its unclear, unclear at what point of the Stream they come out of the Gulf. 8 inch fish. John Graves at VIMS. Doing a genetic study. Age 1, age 2. They come out of the Gulf, move up through the mid-Atlantic, caught around Virginia and Maryland and work their way up the New England coast. Where are they between the ages of 1 and 4? Did catch some 27 inch fish. Smallest ever caught. At this time, those small fish have not been electronically tagged. That’s why the genetics are helpful because we can find out where they’ve come from and where they go that’s how we can figure out they’re migrating patterns.
Barbara Block, PhD We’re striving to put 1000 electronic tags in giant bluefin, combining those studies with studies in molecular genetics. There is one stock in the western, one in the eastern, significant amount of mixing from FL to Bahamas, pop discreet in GOM and northern Canadian waters. That’s one reason that the GOM stock have become giants, little fishing pressure, whereas in the Eastern Atlantic, they’ve been fished for at least 3000 years. If people say that there X numbers of giants, if we have significant overlapping, and we’re counting some of the eastern Atlantic fish in our stocks, then we’re overestimating the number of fish in the western population. So we need to get a better handle of mixing. Mixing is high from East to West, when they come over to feed in Carolina waters. 21 st Century science has revealed that there is a significant amount of mixing. We’re faced with a difficult problem. Do we preserve the biodiversity that we have in the GOM? Are we going to let it disappear, or are we going to take actions to protect it? Can we save giant tunas in the West? Will that come at the expense of N.A. fishers? That may be the only way to help those fish and save them. Close Central Atlantic to intl longlining and put protections in to that protect at spawning grounds? These tagged fish are exceeding depth sensors at 1500 meters. Recreational anglers are critical to our work, and most important to our tagging work has been Captain Gary Stuve, Hobe Sound, on the Leslie Anne, owned by Richard Worley. They have assisted me more than any other team, among many teams, and we released every fish on the boat. Lots of recreational fisheries have helped us. Peter Wright included. Bluefin pass through FL waters come through narrow filter in the Straits and we can see that corridor. Tunas get hot when they conduct courtship and spawning and we can see that in their tags that show their body temperatures rising. In the Western Gulf, they find the optimal waters for spawning, 78-80 degree water. A sign of the decline in their numbers is that you used to see the baby bluefin around. Late 70s and 80s you might see them. The GOM fish are spawning a hundred miles off the northern Texas and Louisiana Gulf Coast. But where are the babies when they leave the GOM? They’re very elusive, and they always have been, but you don’t see them around much anymore. |
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