Saturday, August 27, 2011

ASW, Depletion and Extinction

Dr. Sidney Holt is ASOC's representative at meetings of the International Whaling Commission (IWC) and has decades of IWC experience. The following guest blog by Dr. Holt analyzes the history of determining appropriate catch limits in the IWC.

Many outside observers and commentators assume that when the International Whaling Commission sets a zero commercial catch limit for some whale species  and putative populations it means that stock has been ‘depleted’ (A term little used by the IWC and undefined) and its existence in some way ‘threatened’. That is not so. The zero limits authorized under the New Management Procedure adopted in 1975 for ‘Protection Stocks’ has nothing whatsoever to do with ‘endangerment’. It was, and still is, an implementation of the requirement of the International Convention for the Regulation of Whaling 1946 (ICRW) that the IWC act to “achieve the optimum level of whale stocks as rapidly as possible’. That can best be achieved, according to the scientists, by pausing exploitation.  Exactly the same consideration applies to the Revised Management Procedure (RMP), the moratoria and the designations of ‘no take’ sanctuaries.

In 1976 the IWC decided, for better or for worse, that the overall ‘optimum’ is attained when a stock is at 60% of its original number before exploitation began, the so-called ‘carrying capacity’ or, in the SC’s quaint and faintly sexist, possibly irreligious terms, ‘virgin’. A supplementary requirement of the ICRW is that this be done in such a way as not to “cause widespread economic and nutritional distress.” As far as commercial whaling was concerned it was thought that this would be met by allowing limited whaling on stocks that were found to be somewhat less than the optimum. The decision was not to set zero limits unless the stock was more than 10% below the optimum, that is 54% of the ‘virgin’. That -10% was the subject of prolonged and rather rowdy controversy when the SC was, at a special meeting in Seattle, trying to decide how precisely to implement the Commission’s 1974 decision in principle. Naturally scientists from the whaling countries wanted the cut-off to be much more than 10% less than optimal, others had miscellaneous views; the decision was largely arbitrary, but the consequences of  various options were looked at. Some countries – guess which! – said let’s do the stock assessments, then decide on the cut off, but reasonable caution and natural scepticism prevailed and the various cut-off implications were examined and agreed after simulations had been carried out (admittedly rather primitive ones, given the absence of computers at the time.)

When, very soon after that, it came to looking at Aboriginal Subsistence Whaling the ‘economic distress’ criterion was obviously irrelevant but the ‘nutritional distress’ bit obviously was relevant. So the zero threshold for those activities was shifted down to reflect perceived danger of either extinction or at least possibly irreversible further depletion.

The scientific problem was to know where was that threshold. The scientists thought they knew where was the economic optimum and could estimate it. I was one of them, and I think they were wrong on both counts. But the reality was that if we did not all agree on something there would be no regulation of commercial whaling. Pseudoscientific arguments were offered for 50%, 70%, 80% and we settled on 60%. But where does the threat of extinction loom? In a footnote in the Schedule of the ICRW the Commission has inserted an impossible task for the scientists: “On the advice of the SC (the Commission) shall establish as far as possible a minimum stock level below which whales shall not be taken” and “a rate of increase towards the MSY level (60%for each stock. These last words are unfortunate in giving, as they do, the idea that we humans can tell the whales how fast to breed, how fast to die naturally, and even how density dependent those instructions are to be. So goes international discourse.

The matter was complicated by the Commission’s decision to ask the Secretary to edit the entire ICRW Schedule to get rid of thirty years of legalistic debris. It was decided – quite wrongly, I think – to remove all references to Protected Species on the grounds that the NMP could set zero catch limits. So out of the IWC window went the protection of grey and right whales. But the protected species decisions, from 1931 on, were not about optimization commercial whaling; they were about protecting some seriously depleted species and population from the threat of extermination and if possible allowing their long-term recovery.

As to the Schedule footnote, the first thing to be said is that it reflects the fashionable obsessions with numerical  stock ‘levels’ as if it does not matter whether a threatened population consists mainly of juveniles or a mixture of young and old, or whether it has a viable sex-ratio. But, even ignoring that absurdity the second thing to be said is that none of the population dynamics models or theory used by the SC contains the essential feature of any consideration of an extermination process – that is depensation: the consideration that as a population is depleted at some point the stabilizing (negative feedback) processes creating density-dependence go into reverse so that the rate of population change as the population declines further becomes negative (positive feedback)  That will have very nasty consequences – not just accelerating decline but possible irreversible collapse

An aside: I have noticed that public commentators on climate change – even those working for the BBC- Goodness gracious! – are quite often using the phrase ‘negative feedback’ to mean a feedback process having negative - i.e unwanted by us, even run-away consequences. If one wants stability rather than collapse or chaos negative feedback is just the ticket. That error is even worse than another popular one: citing the speed of a ship as in ‘knots per hour’ (BBC again, sadly). Close of today’s Pedants Corner.

As to the nutritional needs of aboriginal whalers and their families and societies, approaching thresholds for total extinction is clearly not in their interest: they don’t want to go out hunting for rare animals. A rational level – if we really must go on talking about just numbers – is, I suppose, somewhere between that abundance where depensation sets in and the pretty arbitrary level set for the NMP, and which, incidentally, is more or less replicated in the high-tuning version of the RMP agreed by the IWC (but not used by those whalers – Icelandic large-type  fin and Norwegian small-type minke - who now claim to be applying the RMP on a national basis. The question to be put, I suggest, is: What minimum abundance and appropriate population composition makes it worthwhile for aboriginal people to continue their traditions. And, of course, that depends on the changing state of their societies and the availability of other nutritional choices as much as it does on the whales. The subsistence whalers, and the whale-watchers, using as they sometimes do the same whale populations, need the same thing in order to continue their old and new traditions in peace if not harmony: not too few whales, not too many, but just right.

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