Doesn’t sound very appetizing, does it? Why would you eat raw slices of a warm-blooded, pack hunting predator that is on the top of the food chain and whose numbers are critically threatened by hunting?
If you are a bluefin tuna sushi or sashimi eater, you are eating a wild population that is overfished and on the verge of collapse before the oil disaster. You are eating wolves of the sea, warm-blooded pack hunters roaming the northern hemisphere before returning to one of two spawning areas- the Gulf of Mexico and the Mediterranean Sea.
The tipping point is now, this year, this month today. Take home message of this diary for those busy this Father’s Day: Stop eating bluefin tuna, and tell restaurants and fish shops to stop buying it for their customers. Call it a moratorium, not a boycott.
The Miami Herald has an excellent article today entitled "Scientists: Gulf oil spill threatens breeding ground for bluefin tuna" written by Renee Schoof and Reid Davenport for McClatchy Newspapers. link
The sargassum and the warm waters of the Gulf of Mexico are an important nursery and habitat not only for these fish but also for whales, sharks and other big ocean fish such marlin and swordfish. What happens to these top predators will be one important part of measuring the costs of the oil spill to the environment.
Atlantic bluefin tuna spawn in just two places: the Gulf of Mexico and the Mediterranean Sea, and in the Gulf, they spawn in April and May.
Franks said it's possible that adults might avoid the oil and spawn away from it, but that currents would carry their young into it. "It's still speculation on my part, but based on where we collected larvae and the current flows, some would appear to have drifted into the oil," he said.
Greg Stunz, a marine scientist at the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University, said that young bluefin tuna are the most vulnerable.
"Most adults will have or will be moving back to the Atlantic by now, but the larvae and young juveniles will remain and have to deal with the impacts of the oil," he said. "I can't image a small bluefin tuna could handle oil, dispersants, and associated chemicals very well, but we have limited scientific data to tell us how bad it may be."
Still, he said, "given the tremendous overfishing occurring on this majestic species, the spill impact may represent a very serious blow to Gulf populations of bluefin tuna. Will they recover and exactly what those impacts may be are unknown at this time, but most scientists are very concerned."
Here is a link to a comperhensive and very readable story on the peril of the bluefin tuna, including a lot of information on their natural history.
On May 28, 2010, a paper was published the breeding grounds of the bluefin that are close to the Deepwater Horizon oil disaster by Steven L. H. Teo and Barbara A. Block link to pdf of research article They looked at the lines set for catching yellowfin tuna in the Gulf of Mexico and the accidental catching of bluefin tuna on those lines during breeding season. They wanted to instruct conservationists to set locations for the lines so fewer breeding bluefin would be accidentally caught, and also helps define the bluefin breeding area more completely than their earlier estimation with radiotags.
Here are the gorgeous, wild bluefin tuna, racing through the sea. These are not gentle giants like plankton eating whales. They are one of the largest fish in the sea, reaching a size of 1,400 lbs. They are powerful swimmers, attaining speeds of and swim across an ocean basin in only a few weeks. They must keep moving to rush oxygen over their gills and have been clocked at 70-100 km an hour racing after prey in short bursts. Their biological life span is 15-30 years, unless they meet a premature end from attack by a shark or a human.
This is the path to the two spawning grounds (image from http://www.bigmarinefish.com/... courtesy of a book "Close to the Surface" by Greet Wouters."
The two populations are very different, with different average sizes and different ages for the fish to begin breeding. The Gulf breeding populations are larger and older when they breed. link
Here are the eggs of the bluefin- as you can see, these are small and hard to tell apart from other eggs. More on the life history from Forida Museum of National History link
Here are the larvae of the bluefin- courtesy of NOAA, where scientists take a real interest in radio-tagging and tracking the giants as they swim swiftly across the oceans. Atlantic bluefin tuna larvae have only a 1 in 40 million chance of reaching adulthood. So a lot of eggs and larvae need to be laid in order to get an adult. This is the nature of the fish, so each fish lays tens of millions of eggs. That means taking a fish way from the breeding populations will
There is some hope for the bluefin- the news could be a little bleaker.... the breeding and spawning grounds are farther west in the Gulf, a area the oil hasn't reached because of wave and water patterns. Unfortunately, the peak spawning time is the time the BP disaster occured, and the larvae are harder to track because they all look fairly similar at this stage. If the oil gets on their gills or the prey they eat is contaminated, they will be harmed. The dispersants are particularly toxic to fish eggs as well. Unfortunately, the bluefin is not just facing a precarious environment in the Gulf. They are being overfished. Why? Because a single huge fish can command close to a $100,000 when auctioned off for sushi. True, 80% of the fish are eaten in Japan, but we need to bring pressure on a multitude of fronts to affect the end of eating the bluefin.
The ICCAT, The International Commission for the Conservation of Atlantic Tunas - an international group of member nations whose business is fishing regulates bluefin tunas limits. link
ICCAT compiles fishery statistics from its members and from all entities fishing for these species in the Atlantic Ocean, coordinates research, including stock assessment, on behalf of its members, develops scientific-based management advice, provides a mechanism for Contracting Parties to agree on management measures, and produces relevant publications.
To this end, ICCAT statistics and life history data for various tuna species are of some use. link
However, ICCAT has long been criticized by environmental groups for setting the limits to high. In addition, there is little international enforcement on the limits. This link summarizes a lot of ICCAT statistics. It is best to go directly to the link to see the graphs and statistics and a good summary of them. Essentially all the indications are the North Atlantic population is collapsing- 3% of the level in 1960, the amount of biomass (weight of a in the population) returning to the spawning grounds has decreased and fewer juveniles are present every year. link And even with declining populations, ICCAT failed to lower limits for the catch in 2009. Many environmental groups are predicting that in 2009, the population was only 3 years from crash. This what Save the Bluefin said in 2009 BEFORE the spill.
After long meetings the new recommendation sets the quota at for the Mediterranean and East Atlantic to 13,500 metric tons, and that is 13,500 too many. The purse seine fishery gets one month to fish (May 15 to June 15 i.e. an 11 month closure), cancellation of the of the 5 weather days and finally establishment next year of a 3 year rebuilding plan with a 60% probability of stock recovery and easily requiring another major quota reduction to somewhere between zero and 8,000 mt for 2011. In simple terms they agreed that killing more bluefin is still ok, and it's not.
link They are not alone. World Wildlife Fund also condemned this limit.
Sergi Tudela, Head of Fisheries and WWF Mediterranean said,
Mediterranean (Atlantic) bluefin tuna is collapsing as we speak and yet the fishery will kick off again tomorrow for business as usual. It is absurd and inexcusable to open a fishing season when stocks of the target species are collapsing.
Bluefin tuna could be considered an endangered species, with the sharply falling limits. They are not a species that can be easily increased in numbers. Southern bluefin (which breed near Japan) are also considered critically endangered, so now the endless quest for expensive fish is risking wiping out the Atlantic population as well.
Oceana, Greenpeace and the Blue Ocean Institute are urging the United States to pursue a complete moratorium on bluefin tuna fishing in the entire Atlantic basin.
In a letter to the Secretaries of Commerce, Interior and State, the groups made the following recommendations:
The Minimum: Reduce Quotas, Close Fishing in Spawning Grounds Immediately
- reduce the current quota for western Atlantic bluefin tuna to 1,500 metric tons; and 2) consider an immediate closure of all known bluefin tuna spawning grounds at least during known spawning periods. These measures are the absolute minimum that must be done if populations are to have any realistic hope of recovering. If strong measures are not established, the groups argue that the species could soon be "red listed" as endangered under the Convention of International Trade in Endangered Species (CITES).
The role of dispersants isn’t well understood by the public. The dispersants are to save the most fragile parts of the ecosystem- the mangroves and marshes, the birds and mammals. They do this by spraying dispersants on the fresh oil, to break it into little droplets which will chemically and biologically break down faster. The thick oil slicks will hit the shore and be there 35 years later. The dispersed oil hits the shores and the bacteria and natural sun and waves will break the oil down faster. It’s a compromise, and the eggs, larvae and young fish and their food sources, the phytoplankton, are frankly, the losers in the compromise, because they can reproduce quickly and move in from less compromised areas more quickly. The LD50 calculations are based on effects of dispersants and dispersants mixed with oil on model fish and invertebrates. To learn more about dispersants, consult this extensive review published by the National Academy of Science published in 2005. http://www.nap.edu/... Suffice it to say, little is known about the effects of either oil or dispersants on the eggs and larvae of bluefin tuna. The worst case scenario applies here. We may have to use them to save marshes, but we should also honestly acknowlege the extreme risk to the threatened and declining bluefin by their use on the oil gushing from the Deepwater Horizon Unnatural Disaster.
Atlantic populations of the bluefin are threatened on two fronts-historically, overfishing for sushi and now, their little eggs and larvae are under pressure from a toxic mixture of dispersants and oil. Our best case scenario is this- stop eating and fishing the bluefish tuna. This year, next year and into the future until scientific monitoring tells us that the eggs and larvae can survive this insult to their breeding grounds. We need to leave the bluefin mommies and daddies to return to the Gulf and give it another try until the populations can be shown to survive and grow as the water recovers. Picking off the largest and biologically fittest fish won’t work anymore- we need more of them to serve as breeding stock, since don’t know how long it will be until the Gulf’s water quality improves and the marine ecosystem can support the bluefin tuna egg and larvae development. I honestly can’t say how long this should be or will be, but measuring the success of the young fish is critical. link
This week there was radical action by Sea Shepherd reported in the Guardian. link
Green activists using helicopters, divers and rotten butter yesterday confronted Libyan and Italian fishermen to release hundreds of threatened bluefin tuna which they strongly suspect were illegally caught off the Libyan coast.
In the first action of its kind in north African waters, the international crew of the California-based Sea Shepherd Conservation Society released around 800 tuna from a cage being towed behind the Italian trawler Cesare Rustico.
Stocks of bluefin tuna, one of the most valuable but endangered fish in the Mediterranean, have been decimated by ruthless overfishing in the last 20 years to the point where they are now unlikely to survive more than a few more years. Catches are limited to two weeks of the year and shipowners have been given strict quotas by governments, but with little policing, the industry has been easily able to flaunt the law.
So if you want to donate to a group fighting for tuna like they fight for whales, consider donating to Sea Shepherd. Also consider Greenpeace and the Blue Ocean Institute. Please mention other organizations which can lobby for the bluefish tuna in your comments.
Other political action:
Write to my congressman, Nick Joe Rahall, head of the House Committee on Natural Resources and ask for a moratorium to help the bluefin recover from the oil contamination in their spawning grounds link. I hope my letter as his constituant will make a difference, but you all can write and let him know he works for all of us on this.
Let's not love our bluefin to death.
You wouldn't eat a wolf pack. You wouldn't eat a tiger. Why should you eat a bluefin tuna? Please support a moratorium on fishing bluefin and take action personally and politically.