Bigeye Tuna Added To Atlantic Tuna Tagging Project

Good news to announce today, as we are adding Bigeye Tuna (Thunnus obesus) to the ATLANTIC TUNA PROJECT. As we saw last year in the canyons for a short 2 week period, bigeye tuna are incredibly special. Large, nomadic, aggressive, wolf pack hunters and wily, the bigeye is a treasure that we must fight to protect. So today we are officially rolling the protection of bigeye into our efforts. The tagging process remains the same as bluefin and yellowfin. The tags you receive from the Cooperative Tagging Center can be used on bigeye (as well as yellowfin, bluefin and marlin) however here on the site we will be addressing bigeye as a target species we will address. So look for reports on tagging of bigeye, data related to where they travel and how we can take further measures to protect them. For this upcoming season, I am asking all Atlantic Tuna Project network boats to please consider tagging bigeye that you might catch. We are aware that catching these tuna is rare, but we need more data now more than ever. Bigeye tuna are amongst the tuna species most threatened by overfishing. Juvenile bigeye tuna associate closely with floating objects such as logs, buoys and other flotsam, which makes them extremely susceptible to purse seine fishing in conjunction with man-made fish aggregation devices. The removal of large numbers of juvenile bigeye before they reach breeding age is a major concern to fisheries managers, scientists and sport fishermen. (wikipedia excerpt).

Longer-lived than the closely related yellowfin tuna, the bigeye is thought to have a lifespan of up to 12 years, with sexual maturity at the age of four. Spawning takes place in June and July in the northwestern tropical Atlantic, and in January and February in the Gulf of Guinea, which is the only known nursery area for Atlantic bigeye. This is where we think the problems are taking place regarding overfishing of both bigeye and yellowfin.

For the first time ever, NOAA shut down the Hawaii based longline fleet from catching bigeye in the western and central Pacific for the final three days of 2009, having reached the internationally-agreed catch limit of 3,673 metric tons (3,615 long tons). This limit is 30% lower than that of earlier years and will also apply to 2010. The ban does not apply to yellowfin and other fishes or bigeye in the eastern Pacific.

Join me in taking further measures to protect the bigeye tuna. If you have any questions send me a message here on the site.

Tags: Bigeye, CTC, FAD, Guinea, Gulf, Tuna

0 members like this

Comment by Mebachi on April 14, 2010 at 4:51pm: I think this is a great idea, John. It would really be something to see some tagging returns on North Atlantic Bigeyes! Let's hope the improvement in Bigeye production (both recreational and commercial) over the past two years continues. The canyon fishery has been puzzling these past two seasons, with intense July Bigeye fishing, followed by virtually no later season landings by the recreational fleet. Though the depleted East Coast longline fleet continues to harvest some nice autumnal Bigeyes in the southern canyons and off North Carolina. It's definately a positive sign that the species is rebounding from the pounding it took during the mid-nineties at the hands of the pelagic pair-trawl fleet...

This is simply a theory, just a hypothesis based on my observations handling roughly seventy-five percent of the production from this fishery during the mid 1990's:

In 1992, a very clever commercial fisherman/entrepreneur, one who had enjoyed a great deal of success in a variety of cutting edge fisheries and related ventures, imported an extemely large net from Europe and began pair-trawing for tunas at night in Hudson Canyon. It did not take him and his son long to figure out which moon phases were productive and to work out gear conflict issues with the lobster and longline fleets. Almost immediately they started catching large quantities of massive sized Bigeye Tuna, along with many Yellowfin (mostly small) and huge numbers of Albacore.

By 1993, four more pairs of vessels entered this "experimental" fishery which the NMFS limited to ten vessels. Using highly sophisticated electronics, this fleet quickly learned how to catch tremendous quantities of tuna, particularly extremely large size Bigeyes. In 1994, the average dressed weight of the Bigeyes landed in the North Atlantic pelagic pair-trawl fishery was an astonishing 285 lbs! That is the dressed weight! The smallest Bigeyes these vessels produced during this period dressed out at well over 200 lbs. The largest individuals were dressing out at over 395 lbs! Yes, that is correct, over 395 lbs dressed weight! We had to bring Giant Bluefin coffins to the packouts to accomodate these monsters!

These were Super Bigeyes! Virtually every single fish had extremely high fat/oil content. I do not know why this was. These fish were different than the Bigeyes being harvested by the longline fleet fishing the same grounds during the bright moon phases. The very few individuals that were not high quality and obesely fat usually had some sort of disease like Yamai (white cloud) or some kind of debilitating injury.

Through 1994, landings of these gargantuan Bigeyes were enormous. A typical 5-6 day trip by a highliner pair during the darker moon phases averaged around 300-350 pcs of Bigeye, along with tremendous numbers of Yellowfin and Albacore! Thats three-hundred or more jumbo Bigeyes per pair, up to twice a month from late July through October!

By 1995, the average dressed weight of the Bigeyes produced in this fishery was down to about 200 lbs. Landings of Bigeye began to drop as well, but the number of small Yellowfin and Albacore being produced was astromical.

Over the next years, the landings and average size of the Bigeyes harvested by the pelagic pair trawl fleet continued to decline. In 1996, the average dressed weight of a pair trawl caught Bigeye was down to about 165 lbs. The fat content of these fish was much lower and the meat quality inferior. These were completely different fish! In the last year before this fishery was closed, the average dressed weight was only 135 lbs! Long gone were the huge and fatty 250+ pounders!

During the late 1990's, both the declining longline and sport fisheries for Bigeye tuna in the north Atlantic canyons collapsed. Where do you think these fish went?

If you go on an African safari today, you will see lots of elephants. They are prolific in most of the parks and game preserves. But you won't see any of the massive animals with giant tusks that inhabited that continent in early 1900's. Those tuskers have been wiped out for their ivory!

Its just my theory, and I have no background in marine science, and I may be wrong, but I think these enormous Bigeyes were the genetically elite superior Bigeyes, the breeders. Until just last year, Bigeye landings from both the depleted longline and sportfishing fleets in our canyons have been comparatively non existent. Let's hope that the increased Bigeye production over the past two seasons (including some large individuals) are a sign that I am wrong about this...

Comment by John LoGioco on April 14, 2010 at 10:36pm: Hey that is one of the best comments I have ever seen on bigeye history. Can I post that as an update? Yes this season will be most curious. All the data points to another potential disappointment overall when you look at yellowfin, albacore and bigeye. Albacore is another story. Last year they basically didn't show - and that's never a good sign for bigeye as we always used to catch the two speices hand in hand. I am hooked up with some great folks who are working on the Gulf of Guinea issue and together we plan to build momentum for a hopeful NOAA / ICCAT approach. More to come. Great comment, I learned a lot right there. Thanks!