Tuna: A Love Story

  • Richard Ellis
Knopf: 2008. 352 pp. $27.95 9780307267153 | ISBN: 978-0-3072-6715-3

Stocks of bluefin tuna are at risk of commercial and biological collapse worldwide, particularly in the Mediterranean Sea. Scientists are laying the foundations for better long-term management of tuna stocks by including electronic tag data, genetics and microchemistry in their assessment models. Despite their efforts, effective management action could come too late to save this majestic fish.

In his book Tuna, Richard Ellis makes an impassioned plea to rescue the bluefin before it is fished to extinction. Tuna lacks the discipline of Mark Kurlansky's Cod (Jonathan Cape, 1998) but Ellis conveys well the enthusiasm people have for these superbly evolved top predators that are a source of great wealth as well as prized sushi and sashimi.

Much can be learned about fish behaviour from electronic tagging. When I was involved in tracking individual plaice and cod using sonar in the North Sea in the 1970s, the process was arduous and slow. Acoustic tags could transmit for several days, but following them with a small research vessel meant bad weather often stopped the work first. To overcome these constraints we developed small data loggers, which recorded fish depth and sea temperature every few minutes without the need for tracking. Fishermen returned recaptured tags for a small reward and the data allowed us to deduce the vertical and horizontal movements of groups of fish over many months. Some 30 years on, new sensors under trial will soon allow feeding and spawning to be studied in free-ranging fish at sea, rapidly filling important gaps in biological knowledge.

Calls are being made for a global ban on bluefin tuna fishing before it is too late. Credit: R. WILDER/MONTEREY BAY AQUARIUM

Evolving tag technology has made a major contribution to tuna biology. Thirty years ago, Frank Carey built large acoustic tags at the Woods Hole Oceanographic Institution in Massachusetts, and later used them to demonstrate that tuna, swordfish and some sharks can regulate the temperature of some parts of their bodies. Recent electronic tagging programmes have revealed transoceanic migrations of bluefin tuna in the Atlantic, Pacific and Southern Oceans, and shown the widespread dispersion and overlap of Atlantic bluefin populations that segregate to discrete spawning grounds in the Mediterranean and Gulf of Mexico.

Much of this story can be gleaned from Ellis's book, which deals mainly with bluefin tuna but includes yellowfin, skipjack, albacore and bigeye tuna. The chapter about sport fishing, describing millionaires such as popular author Zane Grey who pursued giant bluefin with a rod and line from small boats, is exciting and enjoyable. Other chapters dealing with biology, systematics, commercial fisheries, marketing and ranching are less well focused. Material is distributed haphazardly with much repetition, some sections of text are repeated verbatim and the use of references is erratic. Catch statistics and quotas pop up everywhere and at least six chapters discuss assessment and management of tuna stocks without synthesis. Although the footnotes are models of clarity, the main text is occasionally pretentious, and the lack of a glossary makes it difficult to resolve apparent contradictions in the use of some technical terms. Happily, the book is well illustrated and Ellis's line drawings are excellent.

Tuna will leave readers appalled that Atlantic and Southern bluefin stocks are so close to collapse and that deliberate underreporting of catches by key fishing nations has been a major factor in the tuna's decline. However, the book does not advance any original solutions and the logic of its concluding chapters is muddled. Ellis uses biblical sources to justify conservation and dismisses fisheries management in favour of farming, even though it has been impossible to get bluefin to spawn in captivity until very recently. It would have been more constructive had Ellis weighed the relative merits of both approaches, reiterated the continuing need for strong conservation of wild populations and summarized what can be done.

In March this year, chastened by criticism of its failure to manage the bluefin tuna fishery in the Mediterranean and eastern Atlantic, the European Commission instituted a strong monitoring and enforcement plan to prevent a recurrence of the substantial overfishing of bluefin recorded by European Union member states in 2007 (http://tinyurl.com/6orrrz). By mid-June, when the 2008 quota of 28,500 tonnes was exhausted, the European Commission called a halt to purse seine fishing, which uses the huge drawstring nets responsible for more than 70% of the total tuna catch. It also prohibited transhipment and transfer of fish to fattening cages from either EU or non-EU vessels.

Regrettably, the EC's apparently strong measures will almost certainly fail to achieve stock recovery unless the International Commission for the Conservation of Atlantic Tunas (ICCAT), which sets the quotas, reforms the ineffective 15-year recovery plan it adopted in 2006.

When it meets in November this year, the ICCAT must adopt the measures advocated by its own Standing Committee on Research and Statistics (http://iccat.int/scrs.htm). These include closure of the Mediterranean throughout the spawning season, full enforcement of the increased minimum size for caught tuna, and a catch limit of 15,000 tonnes — less than a third of recent totals — for the next few years. It should also heed the call of the conservation group WWF, which is asking for a three-year moratorium on bluefin tuna fishing (http://tinyurl.com/5ehxtw). With far too many fishing vessels, significant underreporting of catches by several EU countries and considerable illegal, unregulated and unreported fishing by neighbouring states such as Turkey, Croatia and Libya, time is fast running out for the Mediterranean bluefin tuna. Its loss would be an economic and ecological disaster.