Friday, June 12, 2009

Tagging Tuna in the Indian Ocean

Many people believe research is a waste of time and money for small countries like Seychelles. But when you are dealing with fish like tuna that can swim long distances at speeds of up to 70 kilometers an hour, that are heavily exploited and whose trade runs into billions of US Dollars, knowing more about their habits is critical to our own welfare. One of the ways to do this is to put tags on them and when they are fished to get the date of capture, the location and biological details.

I learnt to tag tuna on a Japanese research fishing vessel in the distant reaches of the Seychelles EEZ. That was back in 1987. At the time tuna tagging was only done sporadically and in fact when I returned from that long trip the French scientists working for what was then called ORSTOM were very keen to know the details of the Japanese tagging program.

Now, the results of the first comprehensive tuna tagging program in the Indian Ocean have started to come in. The Regional Tuna Tagging Project –Indian Ocean (RTTP-IO) began in 2002 with an initial tagging project in Mayotte and with feasibility studies. The intensive and large scale tagging began in 2005 and ran up to 2007.

Funding of 14 million Euros was made available by the European Union and the project was implemented by the Indian Ocean Commission (IOC) and supervised by the Indian Ocean Tuna Commission (IOTC). The success of the tagging project depends on the good will of the fishers who recover and report the tagged fish. To date, RTTP-IO says that 26,800 tagged fish have been recovered and reported. The best data comes from at-sea recoveries by tuna purse seiners where the fish can be kept and biological measurement taken.

One of the first results coming out of the project demonstrates that the Yellowfin tuna stock is close to or already being over fished. This is a serious state of affairs and matches other studies that have been done on this species. Assessment of skipjack and bigeye tuna will now be undertaken using the tagging data.

The Indian Ocean tuna fishery is one of the most lucrative fisheries in the world. The annual catch in the Indian Ocean of almost a million tons has a landed value of more than 2 billion US dollars. For Seychelles, as is the case for other involved countries, this industry plays a vital role in the economy. Knowing more about the state of tuna stocks will help us maintain their biological resilience and in turn maintain our own economic resilience.

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