In February of 2009 off the coast of Italy researchers injected Bluefin Tuna with hormones in order to stimulate spawning in captivity for the first time. Previously Tuna farms were of no real benefit since they had to be continually repopulated with wild Tuna. The stationary lifestyle of the farm caused a drop in a particular hormone necessary for spawning with the product being that until now Tuna farms were little more than Tuna holding pens.
There are mixed concerns regarding the success of this endeavor. One being, that as Tuna farms become more profitable and as such, more plentiful, will they have similar adverse effects on the species and the environment that salmon farms have had. It is well known that when you house a large population of fish together in close quarters that parasites and disease run rampant. Another concern is that the fecal waste of a large volume of stationary fish will harm the sea floor below and change the ph of the water in that area, again creating a breeding ground for disease and parasites that may harm wild fish of numerous species in nearby waters. Because Tuna farming is still relatively new, it remains to be seen whether they will suffer these same ill effects. Another concerning question scientists are asking is how does the stationary lifestyle affect how healthy the Tuna is as a food source.
With these concerns though, there is also hope. Hope that young tunas from farmed stocks can help to supplement the dwindling numbers of wild Bluefins. These hopes have become even more vital and important in recent days after the proposal for the ban of bluefin tuna exports at the Convention on International Trade in Endangered Species was squashed. There has also been some promising research showing that farmed Tuna’s mercury levels are significantly lower than that of wild stocks. So even though people are still decimating the Bluefin populations there may be a possible solution on the horizon. At the very least a band-aid.
The two most common methods to catch tuna commercially are “purse seining,” and “long lines.”
A purse seine is a large cylindrical net that wraps around a school of fish much like a drawstring coin purse, except that the draw string opening is at the bottom, toward the ocean floor, rather than at the top. Unfortunately by-catch is high with this method. (Bycatch is unwanted fish and animals caught accidentally in fishing gear and discarded overboard, dead or dying. This bycatch could be sea turtles, dolphins, and numerous species of fish.) The reason that bycatch is high is that in the ocean different species of fish may school together for protection. Tuna tend to school with dolphins because dolphins keep the tuna’s natural enemy, the shark away. Hence the public outcry for dolphin safe tuna.
Good Old Fishing Pole and Line
By far the most sustainable method for catching Tuna is the old fashioned way, with a fishing pole and line. By throwing live sardines and anchovies overboard you can attract a school of tuna. The tuna swarm and you can catch them one by one with little to no risk of catching untargeted species. If on the off chance you did catch something on your line unintentionally you would know it and could unset the hook and release the fish or animal with minimal harm. Unfortunately in the case of the Bluefin, stocks have been so decimated and the mercury levels are such, that one must ask themselves if it is worth it, despite the large profit and high demand.
Posted by Lisa Adza
Mercury is a naturally occurring element but it is usually found in small quantities on the earth’s surface. The bulk of the world’s mercury is inside the earth and is only brought to the surface through volcanic eruption. Unfortunately with the industrial revolution and into the present we have brought mercury to the surface by way of coal. Then, when we burn coal for power it releases the mercury into the air. When it rains the mercury is brought down into the oceans and our planet’s water table.
As mercury is a metal, it is dense so it sinks to the ocean floor where it is eaten by the bottom feeders such as shrimp and small fish low on the food chain. Then a larger fish comes along and eats numerous shrimp, before it is in turn eaten by a still larger fish. Now an even bigger fish like a tuna comes by and eats the medium sized fish, but he doesn’t eat just one. Let’s say he eats thousands of medium sized fish before he is caught and served as Toro in your local sushi restaurant. With each progressive step up the food chain the mercury levels in that animal increase exponentially. By the time you get to the sushi restaurant the mercury levels are very high. Here is a link to a mercury calculator which can tell you how much mercury is in the fish you eat.
Mercury calculator: http://www.gotmercury.org/article.php?list=type&type=75
How does the mercury we get from tuna affect us?
High doses of mercury can be fatal to humans, but even small doses can have an adverse effect. Mercury acts as a neurotoxin and interferes with brain function and development. Recent studies have also shown the mercury is linked to problems of the cardiovascular, immune and reproductive systems. It is possible that it is linked to higher rates of cancer and attention deficit disorder.
“Mercury has long been recognised as a major source of toxicity in children causing reduced cognitive functioning, including reduced I.Q. However, we are now seeing that even ‘low’ exposure levels can cause damage to the developing brain of the foetus and infant. These are mercury levels that are not known to cause acute poisoning or ill health in adults. We also know that mercury is ‘stored up’ in women even before pregnancy. Therefore, preventing exposure to future children means reducing everyday exposure today.”
Gavin ten Tusscher, M.D., Ph.D., paediatrician, Department of Paediatrics and Neonatology, Westfries
Gasthuis, Hoorn, the Netherlands
How much tuna can a human eat and still be safe?
Because of the way tuna passes from mother to child, women who are pregnant or might become pregnant, or who are breastfeeding and young children should not eat more than one small portion (less than 100 g) per week of large predatory fish, such as swordfish, shark, marlin and pike. If they do eat a portion of this fish, they should not eat any other fish during the same week. Nor should they eat tuna more than twice per week.
Does one type of tuna have higher levels of mercury than another, and what kind of tuna is in canned tuna?
Here are some general guidelines I found at the National Cooperative Grocers Association website (address is below).
“Because larger tuna are more long-lived, they have higher levels of mercury. So tuna steaks are higher in mercury than smaller tuna that’s used for canning. In addition, “chunk light” tuna generally has less mercury than “white” or “albacore” tuna. There are some exceptions, however. In one study, 6 percent of the light-tuna samples contained as much or more mercury than the albacore tuna. This might be because light tuna is made from different varieties. While most is “skipjack,” a type of tuna that’s low in mercury, some is “yellow fin,” which has higher mercury content. Unfortunately, albacore is the only specific type of tuna that’s routinely labeled. In addition, imported tuna has tested twice as high in mercury than tuna canned in the U.S. You can ask your grocer about the source of your store’s canned tuna.”References for this article:http://www.ncga.coop/node/2251#tuna
Posted By Lisa Adza
The proposed ban of bluefin tuna exports at the Convention on International Trade in Endagered Species (CITES), which was backed by the United States, was rejected March 18 in a 68-20 vote. Japan, which consumeds 80% of the world's bluefin tuna catch, stated that they would have exempted themselves from the ban if it had been passed. European nations abstained from voting after their amendments to the proposal were rejected.
The only hope for bluefin tuna now is the International Commission for Conservation of Atlantic Tunas (ICCAT), which regulates bluefin tuna fishing but is poorly enforced.
The United States needs to be more involved in ICCAT, please let them know at www.congress.org.
The bluefin tuna are running out of time and need our support!
For more information, go to http://blogs.discovermagazine.com/80beats/2010/03/19/bluefin-tuna-is-still-on-the-menu-trade-ban-fails-at-international-summit/
One way to find out what you are being served is through the use of DNA barcoding. The barcoding allows for researches to identify what kinds of fish a sushi bar may be trying to sell to consumers. Many of these sushi bars failed to accurately indentify the tuna served. According to the article “Only eight of the 22 bluefin samples were labeled “bluefin” on the menus…”. Since the FDA does not require that the eight species of tuna to be placed under their own name for marketing you may not be getting the tuna that you thought you ordered. So next time you want sushi you may want to take along handle-held barcoding device with you and test the fish before you order.
The fishing limit for the bluefin tuna is 22,000 tons per year, but the amount of tuna really being caught is closer to 60,000 tons per year. In the documentary film The End of the Line, Charles Clover shows how 20,000 tons of tuna is being frozen in deep-freezer every year. Mitsubishi also owns 35 to 40 percent stock on the bluefin tuna. If the ban goes through this could mean big money for Mitsubishi as the supply of available bluefin plummets, prices will for sure soar.
According to the article “Save the Fish” by Gywnne Dyer, Stanford University has a program called Tag-a-Giant. The university pays those catching the bluefin in the Atlantic and Mediterranean $1,000 for each tag returned, but only $500 goes to the fishermen in the Pacific. The university tagged 600 bluefin in the North Pacific. Of these 600 tags, 300 have been returned.
In order for the ban to take effect the Convention on International Trade in Endangered Species (CITES) “…needs a two-thirds majority of the 175 member states…” in order for the bluefin to be placed on the endangered species list. It will also take the same majority of votes if it ever comes to pass that bluefin is no longer endangered.
The Mediterranean is where the greatest number of bluefin is caught; the reason being is the Mediterranean is where most of them breed.
Several of the countries within the European Union are against the ban. France and Italy have both asked for stipulations that allow for them to fish locally, and the tuna will only be used for “local consumption”. As Dyer points out, that does not change the number of tuna being caught or the number of fishermen fishing the giants. It only changes whether or not the tuna will be exported to place like Japan. Since the price of tuna sells for a whopping $350 per pound in Japan this could cause tuna to end up on the black market. Not only does Japan feast on 80% of the tuna caught, plus they disapprove of the ban this makes black marketing a possibility.
For these fishermen their whole livelihood is wrapped up in their fishing boats and gear, so to lose their income can have adverse affects on these fishermen and their families. According to Scott Bruce, “Bluefin stocks have never been stronger…”
There needs to be a balance. If Canada is correct, and their stocks are strong and healthy maybe the Convention of the International Trade in Endangered Species (CITES) need to take a deeper look in sustaining jobs as well, and only areas where there is truly a lack of sustainability.
In an article printed in The Salt Lake Tribute, columnist Gwynne Dryer asks that same question, just how bad is it and cites how the market is how we can tell. Currently Standford University’s Tag-a-Giant program is offering $1000 to fishermen who catch Atlantic bluefin and return the tags and only $500 for Pacific showing that currently the Atlantic bluefin is worse off. He also notes that two big sushi restaurants came together to buy a 513 pound tuna from Tokyo’s Tsukjji Market because of the lack of available fish. Dryer states that out of the 600 tags placed on bluefin by the Tag-a-giant program in the Pacific Ocean, only 300 have been returned to the program.
What Dryer calls for is a global effort in order to save the bluefin. He states that those countries who are in agreement with the need to save these fish need to be solidly backing the placement of a ban, which is currently being discussed in the CITES conference that started March 13th. If Nature, as reported in this article, states that nearly 90% of the really large fish are gone, then we do need a global backing to stop overfishing and save these species for future generations to study and enjoy!
For the full article please click the following link:
The convention of International Trade in Endangered Species (CITES) administered by the UN began March 13th in Qatar, having thousands of delegates from 175 nations. During the convention current issues are discussed, such as the prevention from extinction that many endangered animals face. One of the most controversial and prominent debates this year is the proposal to impose a complete ban on the fishing for Bluefin Tuna. Oliver Knowles of Greenpeace stated during the conference, ““The bluefin tuna crisis is one of the most visible examples of how badly we have abused our oceans in recent years, and a damning indictment on the state of global fisheries management. An Appendix I listing is perhaps the last hope for this highly impressive and important fish. Governments must vote the right way.”
One of the strongest opponents to this motion is the country of Japan, a consumer of 80% of the world’s supply of Bluefin Tuna. Representatives from the country stated they would continue the practice of fishing BFT, as it is a part of their culture. However it is very likely that a ban will be imposed. The secretary general of CITES stated there is much evidence that would point towards a move forward on the ban. This is finally a positive step towards the preservation of a species facing eminent extinction.
To learn more:
By Gonzalo Romero
I know that I have been suspect of mercury levels in many different types of seafood and have limited my own consumption of fish thusly. The site tells us that, “for most people—including men, teens, older kids, post-menopausal women, and women who don’t plan to become pregnant—there are no limits on the amount or types of seafood that are safe to eat.” This was news to me, so I went through the calculations my own self to see what would be a healthy amount of farmed salmon would be. “Hypothetical health risks: Your hypothetical health risk from the mercury in farmed salmon begins at a weekly intake of: 199.9 ounces (12.4 pounds)
Meaning that I shouldn’t worry about mercury levels in the salmon I eat until I am eating more than 12 lbs a week for dinner. This is wonderful to know because I am not sure there is any way I could eat that much salmon.
Try out the calculator canned tuna yourself at: http://howmuchfish.com/
Read the whole article here: http://www.sciencealert.com.au/news/20100103-20657-2.html
The proposed international ban on bluefin tuna fishing, which is being discussed at the CITES convention in Doha, Qatar, now has the support of the United States. Tom Strickland, U.S. Assistant Secretary of the Interior for Fish and Wildlife and Parks, has stated publicly that the Obama administration will support the CITES ban until ICCAT is able to enforce its quotas.
"The (tuna) fishery is at risk of collapse," Strickland told The Associated Press. "If we don't take dramatic action, we are afraid it will be too late and we won't be able to recover the species."
Get informed and spread the word!
Read the full story here:
This year, March 13th-25th, the CITES world conference will be held in Doha, Qatar to discuss the proposal to list the bluefin tuna as endangered. This would ban international trade of the species. Japan has vocalized their disapproval of the proposal due to the profound economic and cultural affects it would cause. Although Japan has been in the spotlight as a main objector, other countries would also have to make a lot of changes if this proposal were to pass. The EU in particular acts as a strong advocate for sustaining the bluefin tuna population, however, it seems that they have also been supporting its demise. In a conference with the Green MEP, Raul Romeva commented that:
"While the EU has been talking conservation on bluefin tuna, it has been bankrolling its slide towards extinction. Since 2000, as bluefin tuna stocks have plummeted, the EU budget alone has yielded €34.5 million in subsidies to build or modernize vessels that target this fish. (1) This puts a Euro value on the EU's hypocrisy. The Commission has known for years that the bluefin fleets were too large. It nevertheless allowed Member States to further bloat the fleets with EU aid, supplemented with unknown further funds from their own budgets.
If this proposal should pass it will not only be Japan that needs to make changes, but all countries will have to make economic alterations. The link below is the bluefin tuna proposal for the CITES conference taking place in a couple days.
It’s easy! You’re reading this blog that’s a great first step.
If you love Sushi or have friends that do –
--- Choose alternatives to Bluefin tuna.
If you’re just concerned about sustainability –
--- Become aware of the Bluefin tuna's plight.
The Monterey Bay Aquarium provides information and materials in a section called “Seafood Watch”. Check out their site and find others ways.
“You” can make a difference.
Escolar is a dark brown color fish which is sometimes marketed as “butterfish”, it grows up to 2m in length. The consumption of Escolar is an issue, the fish cannot metabolize wax esters from its diet. This means the oil contents in its meat consists of 14-25%. The wax esters may cause gastrointestinal distress, AKA diarrhea, which would occur 30-36 minutes after consumption. An example of a consumer’s experience can be found here…http://paxarcana.wordpress.com/2008/02/12/sometimes-it-makes-orange-oil-shoot-out-of-your-ass/
Wired magazine reported a group of scientists working on a research project to identify tuna sushi with DNA barcodes. The group ordered from 31 sushi restaurants and 5 out of those were serving escolar as tuna. Half of those restaurants misrepresented or were unable to clarify the fish they were serving.
The project taken up by the scientists could potentially benefit regulation and penalizing of eateries serving endangered species. The group is currently cataloguing their results in a large database called FISH-BOL. The database has data acquired with specific techniques called DNA Barcoding. Once the database is complete anyone with a handheld DNA reader can easily identify the fish specimen within minutes. This could be greatly beneficial as it would make bluefin tuna easily identifiable, therefore making the enforcement or regulatory consumption easier.
To find out more about the FISH-BOL project go to:
Posted by: Gonzalo Romero
Check out the website at
So what is the tuna treated with? According to “Tuna’s Red Glare,” an article posted in the New York Times, tuna may be red because it has been sprayed with carbon monoxide. This is alarming to find, as color is often used to determine freshness.
Some retailers report an increase in tuna sales after switching to the tuna treated with carbon monoxide. According to “Tuna’s Red Glare,” red tuna does not necessarily indicate fresher tuna. The freshest bluefin tuna is actually pink.
But deception easily follows. Bluefin tuna can also be known as “red tuna.” Spraying the tuna with carbon monoxide gives it an enticing red color. Surprisingly enough, tuna turns brown quite quickly; it is actually hard to get to consumers in time before turning brown. And the tuna, which was once a seasonal item, is now available all year. Not to mention, it often takes tuna a long time to finally reach its destination, so good color is hard to maintain.
The FDA approves the process of treating fish with carbon monoxide, but many countries including Japan and Canada ban the process because “it could be used to mask spoiled fish.” That is scary to think about. I like to make informed decisions about what I am eating. Spoiled fish for dinner tonight? Thanks, but no thanks. There are already enough reasons not to eat bluefin tuna, and the possibility of eating it spoiled just solidifies my choice.
Image found at: