Status of Nauru's tuna fisheries assessed by SPC

One of the world's leading tuna scientists, Dr Donald Bromhead of the SPC Oceanic Fisheries Programme is in Nauru this week to finalise the Nauru National Tuna Fisheries Status Report (NTFSR).
As well as assessing these migratory tuna stocks across the whole regional ecosystem, SPC also advises its island member countries individually about the science behind the tuna fisheries within each Exclusive Economic Zone (EEZ).

Nauru's EEZ is about 320,000 square kilometres in area and on the map Nauru is just a tiny point of land (21 square kilometres) within this huge ocean area.



Don Bromhead (SPC) and Charleston Deiye (NFMRA CEO)

However, as Dr Bromhead explained, Nauru's EEZ is very well-situated in the path of the Tropical Convergence Zone - an oceanographic feature that sweeps eastwards and westwards through Nauru according to the state of the Southern Oscillation Index (El Nino - La nina) and carries with it the best tuna purse-seine fishing conditions in the Pacific.

These climate-driven fishing conditions are not predictable, but in a good year Nauru can earn over A$10 million from licencing foreign purse-seiners to fish in the Nauru EEZ.

However, there is a price to pay for the stewardship of this natural resource. Dr Bromhead explained that although skipjack tuna stocks are extremely healthy, you can't purse-seine for skipjack without catching yellowfin and bigeye tuna as well. And there are currently too many bigeye tuna being caught, both region-wide and in the Nauru zone, for the stock to replenish itself and maintain fishing at maximum levels of productivity. To make matters worse, although SPC has known for some time that many fishing vessel crews cannot reliably tell the difference between small bigeye and yellowfin tuna, and have probably been inadvertently reporting some of the bigeye they catch as yellowfin, it has just been discovered that this misidentification problem is more widespread than feared.

All of this means that the countries of the region, Nauru included, need to reduce the catch of bigeye tuna, particularly small bigeye tuna, as a matter of urgency if the fishery is not to be damaged. The good news is that it may be possible to reduce the unsustainable catch of bigeye without impacting sustainable catches of skipjack by reducing fishing on drifting Fish Aggregation Devices (dFADs). Most bigeye, in the Nauru zone at least, are caught around dFADs.  Nauru has already committed to this reduction and regulations are being prepared that will prevent foreign purse-seine vessels from fishing on dFADs in Nauru waters in August and September of 2009, along with a suite of other industrial tuna catch-control measures that will take effect from January 1, 2010.

The Nauru National Tuna Fisheries Status Report is a comprehensive up-to-date compilation of all the available scientific information about the role of Nauru's EEZ in the Western Pacific regional tuna fishery. It has taken over 12 months for SPC to compile and the final report will be submitted to the Nauru Fisheries and Marine Resources Authority in a month's time.

Dr Bromhead's visit to Nauru to discuss and present the main findings of the report was made possible by the AusAID/Nauru Fisheries Management Institutional Strengthening Project.