By JEREMY CHERFAS Tough decisions were studiously avoided at last week’s annual meeting of the International Whaling Commission. Iceland walked out, it is true, but had decided to do so last year. And Norway decided to resume commercial whaling. But those decisions were essentially outside the IWC. Within, the French proposal to set aside Antarctic waters as a whale sanctuary was put off to another day. Requests from Japan for a continued kill of minke whales in Antarctica for ‘scientific research’ were granted with no more than a gentle rebuke. It was not until the last day that delegates to the Glasgow meeting really bit the blubber on a resolution that split the ranks of whalers and non-whalers alike. The resolution accepted the scientific engine that will calculate catch quotas, but added numerous features that need to be in place before the engine is used, as part of the Revised Management System (RMS). Japan and Britain found themselves united in abstaining over the resolution: Japan because it did not like those additional features, Britain because there was no mention of reducing the cruelty involved in whaling. The only country to vote against it was Norway, because it doesn’t like the quota-setting calculations. The resolution was, however, adopted by 16 votes to 1, with 11 abstentions. At the heart of the conflict that has divided countries that say they will accept whaling provided it is properly regulated, from those that want to whale, is a simple question: how many whales can one kill? That question has exercised the brains of the IWC’s scientific committee for more than five years. But at last they have a set of rules on which they agree. These rules, now endorsed by the IWC, form the catch limit algorithm at the heart of the Revised Management Procedure (RMP). The job of the RMP is to provide a rational basis for exploiting whales. Its forerunner, the New Management Procedure (NMP), was essentially a simple model of a population. Left alone, under pristine conditions, animals are born and die, and the total population depends on the ‘carrying capacity’ of the environment. Removing some animals will free resources for those remaining. These will flourish, creating a surplus that can be exploited. Simplistically, the population can be reduced by hunting to a level at which it produces the maximum sustainable yield (MSY), the greatest harvest that can be taken year after year. Take more than this each year and you eat into the natural capital, depriving yourself of future yield. Take less, and you are unnecessarily forgoing some yield that you could take. The scientists who devised the NMP decided that the MSY would be provided by a whale population reduced to 60 per cent of its pristine abundance. One safety feature to preserve numbers was to set the maximum catch quota at 90 per cent of the MSY. A second was to insist that if a population fell below 54 per cent of its natural abundance, it would be completely protected. In a perfect world, the NMP would have worked. Given accurate information about such things as the rate of reproduction, age at first reproduction, rate of natural mortality, population age structure and the like, the NMP could have managed whaling adequately. The problem was that the biological data were almost impossible to come by at an acceptably accurate level. Whales are difficult and expensive to study, and commercial whaling does not provide statistically sound data. As long as that was true, scientists who used the NMP to set quotas could fudge the issue by using estimates that in the 1960s gave larger quotas than were wise. Later, as conservationists gained the upper hand, quotas grew ever smaller. In 1982, conservationists eventually forced through a moratorium on commercial whaling that began in 1985/6. During the halt, the scientists would come up with a revised management procedure that made good the deficiencies of the NMP. There were objections to this approach from the whalers. Johann Sigurjonsson, chief scientist in the Icelandic delegation, was indignant during his country’s valedictory after walking out of the IWC. ‘Iceland manages cod, all the time revising the management procedure, but we don’t stop catching cod while we are revising. So, why do we need to stop catching whales while you are revising management procedures?’ Ideally, a management procedure would not put an existing population at risk of extinction, it would offer a high quota, and the quota would not swing wildly from year to year. But you can’t have everything. The most risk-free strategy is to take no whales. That is stable, but offers no yield. Deciding the relative importance that should be given to yield, stability and risk, the scientists argued, was a job not for them but for the Commission. For four years, the IWC failed to set priorities for the RMP. Finally, in 1989, it attempted to give scientists the guidance they sought. Minimising the risk of taking whales from a depleted stock was given top priority. Next in importance was to maximise the stability of the quota from year to year. And finally, the procedure should offer the highest total yield over the long run. With that guidance, it became pos-sible to test rival management strat-egies. Australian population biologist William de la Mare had proposed a high-stakes computer game: put up a set of management rules, and apply them to a stock of whales in a computer. The winner gets to manage whales in the real world. Each set of rules had different strengths and weaknesses. One set was risky, allowing a catch from populations that were not reproducing very quickly. Another was inefficient, in that it was both risky and offered a poor total yield. The winner was the most balanced. It allowed catches even from depleted stocks, but at a level that barely affected their recovery. The catch limit algorithm adopted, called the core C procedure, was devised by Justin Cooke, a British population biologist based in Germany, who represents the World Conservation Union (IUCN) at the IWC. Rather than relying on estimates of the biological parameters, such as breeding rate, that proved the un-doing of the NMP, Cooke’s algorithm needs only an estimate of the number of animals in an area and, if available, the number of animals taken in past seasons. Those data go into an assessment process in which the biologically important parameters are allowed to vary between reasonable limits. So, at first, there might be a great deal of uncertainty about a stock’s level of depletion; it might be at 30 per cent of its pristine level, or at 60 per cent. Also, the reproduction rate might be anywhere between zero and 5 per cent. Estimates of abundance will not only vary, they may also be systematically biased. To arrive at a catch limit, the algorithm is run thousands of times. Each time it picks at random a subset of the estimated parameters within their set limits, and each time it calculates a separate value for the catch limit. The result is a distribution of possible catch limits which reflects the uncertainty in the data (See Graphs). The actual catch limit is set by the ’42nd percentile rule’: 42 per cent of the calculated catch limits are below the chosen limit and 58 per cent above it. This limit was chosen to satisfy the Commission’s requested balance of risk and reward.FIG-mg18293001.GIF In later years, so the theory goes, more data are available. More surveys might have been carried out, and there will be catches from recent hunts. These allow the asses-ment procedure to improve its initial vague ideas about stock size, level of depletion, and other factors. As a result, the distribution of possible catch limits narrows, and the actual catch limit tends to increase. The beauty of the core C algorithm is that it is conservative and robust. The scientific committee tested it to the limit under a wide variety of assumptions, and it generally gave the desired combination of safety, stability, and yield. Systematic bias, different historic catch patterns, different underlying population models, and unpredictable catastrophes all barely perturbed the outcome. The algorithm does not even need frequent surveys to be carried out, although there may well be an incentive for whalers to provide survey data because additional information will almost always increase the catch limit (See Graphs). Also, as a safety measure, if there has been no survey for five years, a rule is triggered that decreases the catch limit by 20 per cent a year. The core C procedure works, at least on computer populations. It satisfies the criteria set by the IWC, offering a quota on stocks above 54 per cent of their original abundance (a number chosen so that the RMP appears at least as safe as the NMP), while allowing stocks to recover quickly. It has been set to work on the two stocks of whales most likely to be hunted: the minkes of the northeast Atlantic, wanted by Norway, and those of the Antarctic, wanted by Japan. The results are still stuck in the computer, because the scientists did not want to calculate quotas – potentially legitimising the claims of Norway and Japan – before the IWC had adopted the algorithm. In the northeast Atlantic, according to one scientist who really understands the Cooke algorithm, the quota would be ‘in the hundreds’. And in the Southern Ocean, where the minke population is estimated at 760 000, and where a total of about 100 000 have been taken since the 1970s, the algorithm would allow whalers to take another 100 000 whales over several decades. Several countries, notably Britain and New Zealand, take exception to any commercial whaling. Others have no intention of whaling themselves, but seem willing to let other countries do so, provided there are strict controls in place. The catch limit algorithm is just part of those controls, which is why it has been wrapped up within what has become the RMS. This, proposed by Australia and others, ties the quota-counting engine to additional components such as minimum standards for data, guidelines for conducting useful surveys, and an effective inspection scheme to verify and police catches. A year’s delay was built into the RMS. The 16 nations supporting it want time to consider the additional components. If they vote for the system at next year’s IWC meeting in Tokyo, commercial whaling could again become a reality. In past years, the whalers have exploited loopholes in the IWC convention to remain afloat. Their patience might now be rewarded. The science that both sides have always turned to will be saying: ‘Yes, you can kill X minkes in the northeast Atlantic this year, with acceptable risk to the population’. The question then will be whether the Norwegians stick to the limit? And how will those who still want a whaling ban justify a position that, at base, owes everything to emotion and nothing to science?