The real final draft with sources of Southern Bluefin Tuna

This topic submitted by Rebecca Weber ( at 4:28 PM on 6/24/03.

Check out this huge M. annularis and accompanying fish at Molasses Reef, Key Largo, Florida.

Tropical Field Courses -Western Program-Miami University

The Decline and Management of the Southern Bluefin Tuna

Rebecca Weber

The market for fish around the world is extraordinarily profitable. One hundred years ago, man’s ability to remove large numbers of fish from the ocean was limited and caused no real threat to any species. Advances in technology have facilitated man’s ability to supply large numbers of fish to consumers. Due to the market’s promise of wealth, many have tapped the ocean for its bounty. However, there have been many detrimental externalities that are associated with the progress of technology and the desire for wealth. The quantities of fish extracted from the ocean are larger than ever before, and the commercial fishing industry has been accused of depleting the world’s fish populations to a mere fraction of what it once was.

The southern bluefin tuna (SBT) is one such species of fish which has been fished to dangerous levels. For over 50 years the SBT has shown a steady and dramatic reduction in population size. Their numbers are so low there is speculation as to whether or not they can reproduce fast enough to accommodate the numbers being taken. Yet, they are still being fished. With all the fish in the sea, it may seem easy enough to just stop fishing this one species for a while. A pricey delicacy in Japan, however, the high dollar amounts generated from the SBT industry make getting people to stop fishing it a difficult task. Faced with the extinction of a species, inadequate and conflicting science is partly to blame for the continued harvest of this precious animal. But, the difficulty in denying people jobs, customs, wealth or extravagance plays the major roll. The management of the SBT has been for years and continues to be a topic of debate and international law. The issue is a complicated one in which deciding who gets to take how many, from where, and when is rarely agreed upon.

The Southern bluefin tuna (Thunnus maccoyii) is an amazing creature. They are large, highly migratory, pelagic fish that live for the most part between the latitudes of 30 and 60 degrees south. They can live as long as 40 years. The SBT can reach a maximum weght of about 220 kg and a maximum length of about 220 cm, although, due to over fishing a catch of a fish this size is rare. Because of their gill structure and the way that they breathe they remain in motion throughout their entire lifetime swimming their body length every second (Earle). For short bursts they can reach speeds of almost 70/km per hour. The only known spawning ground for the SBT is the Indian Ocean south of Java Indonesia. They spend most of their lives, however, in their feeding grounds off of the southeast, southern, and southwest coasts of Australia. Interestingly, their highly migratory nature will carry them thousands of miles in a single year, reaching as far away as the southern tip of Africa (Earle) There is still speculation, due to lack of hard science, as to when the SBT reaches sexual maturity, but generally ideas point to between 8 and 12 years of age (FAO). This late breeding age is a main factor leading to the species depletion because often they are harvested before they have had a chance to breed.

The bluefin tuna has long been prized as the fattiest of the tuna species. The fatty lipid content of bluefin meat makes it one of the most sought after fish for sushi and sashimi connoisseur (ICCAT). Japan, known for their sushi and sashimi, is the largest consumer of bluefin tuna in the world. Although prices range considerably depending on its size, whether fresh or frozen, and how it was handled, the average SBT sells for between $20,000 and $40,000. Last year a distributor in Tokyo paid almost $260,000 for one 202 kg fish at an auction. “The final price, which put the fish at $1,284.68 per kg, broke the previous record high in 1998 of $578.09 per kg, said an official at Tokyo's Tsukiji fish market, the world's biggest (National Post). Because of the high price and, as will be discussed later, the low fish numbers “southern blue fin tuna is used exclusively by restaurants (Doulman 116). SBT is a delicacy eaten by business men usually when eating dinner on the company card. With a single fish fetching such amazing prices, the difficulties in curbing fishing of the SBT are easily understood.

The bluefin has been fished for thousands of years. Before commercial fishing began in the mid 1950’s the SBT was cheap and primarily used in dog and cat food, usually selling for as little as 5 cents a pound. The advent of better refrigeration techniques of the mid ‘50’s allowed for transportation of fresh SBT to far away countries. During the late 50’s, the Japanese began to view the SBT as the most prized and sought after fish for sushi and sashimi (Doulman 116). Early fisherman caught the SBT in their spawning grounds south of Java, but soon after almost all fishing moved south below Australia. This was due to the larger fish size catch as well as the higher quality (fatty) meat. “High fat levels are encouraged by cold water temperature (Doulman 107).

By the early 60’s SBT harvest was in full swing with total catches reaching about 80,000 tons per year (Baldock). The mid 1960’s, just a decade or so after the first major commercial fishing of SBT, brought a noticeable decline in total catch down to around 60,000 tons. Tagging studies began to be conducted to gain knowledge about this prized creature. With the development of air freight in the early 1970’s, more and more bluefin were being caught for the Japanese market. By 1980, SBT catch was down to 40,000 tons, just half of its numbers 20 years earlier. Bluefin tuna numbers have continued decreasing drastically ever since.

The bluefin tuna is in grave danger of extinction. As fishing continues, the SBT numbers fall every year. As numbers dwindle, smaller fish that have not reproduced yet are being taken out and sold. An ICCAT, International Commission for the Conservation of Atlantic Tunas, study says Atlantic bluefin, a relative of the southern bluefin tuna being fished to the same incredibly low numbers, has fallen way below their maximum sustainable yield (ICCAT). Maximum sustainable yield is the largest amount of fish that can be removed at a sustained rate without populations declining. Bluefin tuna have dropped below this number, yet they are still being fished.

So, what if anything is being done to protect this dying species? By the 1980’s, some researchers believe that the SBT total biomass was down to just 10% of what it was during the early 60’s (Franklin). The principle SBT takers Japan, Australia, and New Zealand recognized the decline of the species and in 1985 imposed voluntary catch quota of 37,000 tons globally. While this was a good start, numbers continued to decline and in 1989 the three countries reduced their quotas further to a Total Allowable Catch (TAC) of 11,750 tons between them. Japan, Australia, and New Zealand were each allowed 6,065, 5,265, and 450 tons respectively. Unfortunately the true global catch was probably closer to 17,000 due to the continued fishing by Indonesia, Taiwan, and Korea which did not impose quotas on themselves. Following the laws of supply and demand, as the number of SBT available went down, prices were driven up.

Until this point, almost all fishing was done using the long line method. What this means is that a boat goes out and releases hundreds of miles of fishing line with fish hooks every few hundred. There are radio beacons every so often as well in order to facilitate the pulling in of the lines without loss. Slightly before 1990, Australia began to use the purse-seine method of fishing. This method involves one boat with a small net towing boat, or two large boats working together. When a school of SBT is sighted, the smaller boat drives out around the school towing a net whose other end is still connected to the main boat. The boat surrounds the school, and then comes back to the boat where the net is then drawn in and together, closing it like a purse (FIGIS) The fish are trapped.

In order to increase profits with such low quotas, Australia decided to increase the weight in fish they could sell without taking it out of the oceans. The first experimental tuna farm was established in Port Lincoln, SA in 1990. Using the purse-seine method, fish were dragged for, at times between 200 and 300 km back to the coast. Juvenile fish weighing around 20 kilograms are caught from December to May off the South Australian coast, and fattened to 30 kilograms in sea pontoon cages before being exported to Japan (CCSBT). This method has been very successful in increasing quantity supplied while still sparing SBT in the ocean. In 1998, there were twelve 20 hectare farms. Farm production of southern bluefin tuna increased from 97 tons in 1991-92 to 2,089 tons in 1996-97; the value increasing from $2 million to $40 million in 1996-97 dollars (ABARE). Japanese fishermen continue to use the long line method as it is not feasible for them to pull tons of fish all the way back to their native ports.

“On 20 May 1994 the then existing voluntary management arrangement between Australia, Japan and New Zealand was formalized when the Commission for the Conservation of Southern Bluefin Tuna (CCSBT) which had been signed by the three countries in May 1993, came into force” (CCSBT). The CCSBT was another step in the right direction to protecting the SBT. Its main purpose was to increase SBT stock levels back to their 1980 level by the year 2020. However, there were almost constant debates about the health of bluefin population. Aerial surveillance and tagging studies showed clearly that stocks continued to be too low. Studies are unclear however. The SBT at times dives to 300 meters below the surface, and migrates great distances. Recovering tagged tunas is difficult. Newer tags have recently been developed that transmit data collected to a satellite, but that information takes time to process. Japanese scientists took the stance that the measures in place today were enough to allow the SBT stocks to replenish themselves. Australia and New Zealand took more of a precautionary approach saying they believed more needed to be done to save the tuna. They agreed however that more research was necessary.

In 1995 Japanese fisherman began taking more than their TAC claiming they were for an “Experimental Fishing Program” (EFP). Once experimented on, the fish were then sold at auction as normal. Australia and NZ were unhappy about this and believed it to be a clear violation of the CCSBT agreements. Not only was the taking of more fish purely an issue of economics in the eyes of Australia and NZ, but they believed taking that many more fish would hurt the stocks significantly more than the knowledge gained could help. Japan halted its EFP during negotiations, but when still not resolved in 1999, began again allotting themselves another 2000 tons (Baldock). After Japan’s EFP went back in to effect, Australia and NZ banned all Japanese boats from their ports. Environmental groups succeeded in getting the SBT on to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) endangered species list. Continued legal battles ensued when Australia and NZ brought Japan before the Australia and New Zealand instigated compulsory dispute resolution proceedings under the United Nations Convention on the Law of the Sea (UNCLOS). The outcome was as follows. Japan was to immediately halt the EFP, and the three countries were to continue negotiations until resolved (Baldock).

On June 4th, 2001 all ports were reopened to Japan as a measure to smooth over negotiations. A deal was made wherein Japan would “pay back” the 711 tons it took above its quota for its EFP by taking it out of its next year’s allotment. “Japan believes it is legally entitled to restore that tonnage to its quota, though it has so far compromised by accepting only 356 tons -- about half of the 711 tons it wanted” (Thornton). Australian fishermen are obviously angered by this allowance because they feel they are missing out on income that Japan is being granted.

Korea and Taiwan have both joined the CCSBT October 2001 and August 2002 respectively. The CCSBT has been attempting the persuade Indonesia to join. Indonesia poses a great risk to the species because its boats fish the SBT right below the island of Java, the spawning zone, often taking immature fish. Presently, current SBT catch quotas remain the same with no immediate plans for change. “The CCSBT is developing a status of "cooperating non-member" to allow fishing nations to engage with the Commission without becoming full members. This status is expected to take effect in 2003 and Indonesia is expected to be the first country to take advantage of this arrangement” (CCSBT). Also, the second year of their major tagging and recapturing program for continued scientific study began on December 4th 2002. There is no question that the southern bluefin tuna is endangered. The greater the number of nations that join the CCSBT, the better able they will be to accurately calculate total SBT harvests as well as remaining population size. However, we are pushing the limits on how many more we can take before we lose this species forever. We are walking a tightrope wire, yet we do not know where our next step will land.

Next Article
Previous Article
Return to Topic Menu

Here is a list of responses that have been posted to your discussion topic...

Important: Press the Browser Reload button to view the latest contribution.

If you would like to post a response to this topic, fill out this form completely...

Response Title:

Optional: For Further Info on this Topic, Check out this WWW Site:
Response Text:

DOWNLOAD the Paper Posting HTML Formating HELP SHEET!

We also have a GUIDE for depositing articles, images, data, etc in your research folders.

Article complete. Click HERE to return to the Pre-Course Presentation Outline and Paper Posting Menu. Or, you can return to the course syllabus

  • Tropical Marine Ecology of the Bahamas and Florida Keys
  • Tropical Ecosystems of Costa Rica
  • Site NAVIGATION--Table of Contents

    Listen to a "Voice Navigation" Intro! (Quicktime or MP3)

    Search WWW WITHIN-SITE Keyword Search!!



    Hays' Marine Ecology Images and Movies Ohio Bird Photo Collection | Tropical Bird Collection | Costa Rica Image Collection | Edge of the Farm Conservation Area | Hays' Tarantula Page | Local Watershed Fish Studies| Wildflowers, Arthropods, ETC in SW Ohio | Earth Science Resources | Astronomy Links | Global Change | Marine Ecology "Creature Study Guide" |


    | Educational Philosophy | Discovery Labs: Moon, Geologic Time, Sun, Taxonomy, Frisbee | Project Dragonfly | Vita |Field Course Postings | Student Research Postings | Nature/Science Autobiography | Environmental Programs at Miami University


    Daily Necessities: Macintosh Resources |Search Engines | Library Resources|Server Stats| Family Album | View My Schedule | View Guestbook | Western College "Multimedia Potpourri"

    It is 3:48:24 PM on Thursday, July 2, 2020. Last Update: Wednesday, May 7, 2014