The report compiles the scientific records of the different major tuna stocks done by each of the Regional Fisheries Management Organisations (RFMOs) into one document, serving as a one-stop resource for comprehensive tuna stock information.
The Status of the Stocks Report uses a colour rating system to indicate varying degrees of stock heath and ecosystem impact.
The most notable update since the last version released in November 2015 is that Indian Ocean yellowfin stock assessment indicates a decline in status.
Overall, catches of Indian Ocean yellowfin have declined by 19 per cent from a record high of 530,000 tonnes in 2004, but seem to be increasing again, especially in purse seine and other fisheries. The stock is estimated to be overfished and overfishing is occurring due to an increase in catch levels in recent years.
About the Report
There are 23 stocks of the major commercial tuna species worldwide – 6 albacore, 4 bigeye, 4 bluefin, 5 skipjack and 4 yellowfin stocks.
The Status of the Stocks summarises the results of the most recent scientific assessments of these stocks, as well as the current management measures adopted by the RFMOs.
In addition, this report ranks the status and management of the 23 stocks using a consistent methodology in terms of three factors: Abundance, Exploitation/Management (fishing mortality) and Environmental Impact (bycatch).
In 2014, the catch of major commercial tunas was 5 million tonnes, a 4 per cent increase from 2013.
Fifty-seven per cent of it was skipjack tuna, followed by yellowfin (27 per cent), bigeye (9 per cent) and albacore (6 per cent). The four stocks of bluefin tuna account for only 1 per cent of the global catch.
Different fishing gears are used to catch tunas. Purse seining accounts for 64 per cent of the global tuna catch, followed by longline (12 per cent), pole-and-line (9 per cent), gillnets (4 per cent) and miscellaneous gears (11 per cent).
Globally, 48 per cent of the stocks are at a healthy level of abundance, 39 per cent are overfished and 13 per cent are at an intermediate level.
In terms of exploitation, 48 per cent of the stocks are experiencing a low fishing mortality rate and 17 per cent need stronger management to end overfishing.
When viewed from the point of view of total catch, 78 per cent of the catch comes from healthy stocks. This is due to the fact that skipjack stocks contribute more than one half of the global catch of tunas, and they are all in a healthy situation.
In contrast, most bluefin stocks and 2 out of 6 albacore stocks are overfished, but combined they make-up a relatively small fraction of the total catch. In terms of fishing mortality, 13 per cent of the total tuna catch comes from stocks where fishing is not well managed.
