Can You Save Everything?When is a common dolphin not a common dolphin? Mark Simmonds and Frank Cipriano explore one of the great dilemmas of modern conservation - what should we be protecting?
As we write, we are sitting in that strange beast, the Scientific Committee of the International Whaling Commission. Here, a surprisingly big gang of people meet each year for two weeks to discuss the situation of the worlds whales. Big picture conservation.
At the moment, however, weve got something else on our minds. Its some big picture philosophy, really. Were asking ourselves what exactly it is we are trying to conserve. The thing is, most conservation work focuses on the species. But what exactly is a species, why is it so important and is the approach weve chosen the most appropriate one?
Well, a species is usually a group of animals that are genetically different and which do not normally interbreed with other species. Different species are also typically, but not always, physically distinct. So, for example, we are one species and chimpanzees are another, although there is surprisingly little difference between our genetic codes (our DNA ). Sadly chimpanzees, like all great apes, are critically endangered.
The river dolphin species are in similar trouble and one, the baiji, very sadly, recently became extinct. The most numerous species is the boto of the Amazon and Orinoco river systems of Latin America, but the pressures on it are considerable, including its increasing use as bait for fishermen. Significantly, a new river dolphin species was declared this year - or to put it another way, the boto was divided into two species.
The new Bolivian dolphin was swiftly adopted by the Bolivian government as a symbol of the countrys conservation efforts, illustrating the power of an endangered species designation and hopefully meaning that Bolivia will now move heaven and earth to conserve it. The Bolivian species is smaller and a lighter grey. It lives only in the Bolivian Amazon, isolated from the other Amazon River dolphins by a series of 18 rapids
between Bolivia and Brazil.
So, for river dolphins, the species focus may be helpful to their conservation. Generally, if something which is a distinct animal species can be seen to have perilously declined, it may be given the special designation as an endangered species and this is when the alarm bells ring loudly and efforts tend to follow.
But this is not the whole story. The process depends on being able to recognise a group of animals as a distinct species (and one that is in trouble). This is not straightforward for many whales, dolphins and porpoises, which spend most of their lives hidden from view.
An exclusive conservation focus at species level could also mean that local populations could be depleted and eventually even exterminated, but because the species persists with healthy populations elsewhere, the plight of the local population does not provoke strong (or perhaps any) conservation actions. In the conservation world there is always a lively debate running on where to focus funds and energy. At the moment species rule as the focus for conservation action!
Enough theory - here are some examples: The harbour porpoise in the Baltic Sea has virtually disappeared, and there is an argument raging about how much this matters because there is a question of whether or not the Baltic porpoises are genetically distinct from those in the North Sea. The harbour porpoise is a very widespread species, so even the denuded situation in the Baltic is no great threat to the species as a whole.
Another example is provided by the common dolphins of the North East Atlantic. In this case, there is a major bycatch problem (accidental capture in fishing nets) to the south of the UK. Many thousands of dolphins are killed here in nets each year. However, the number of common dolphins in the region (from Iceland to Africa) is estimated to total over 700,000. So, it is argued that this doesnt matter... much. Now, if it was accepted that the common dolphin in this region represents several distinct populations, for which there is actually some evidence, the deaths of several thousand animals - or even several hundred - would be regarded as far more significant.
Similarly, a UK nature conservation agency is arguing that disturbance of whales, dolphins and porpoises can only be an offence if a significant population unit, meaning a proportion of a known population, is disturbed, for example 4,600 porpoises. We do not agree that this is appropriate or even vaguely practical.Matter of perspective
The fourth example brings us to whaling. Any notion that whale hunting can be sustainable is based on a starting point of a population of a calculated size. However, we regularly hear the whaling nations talking about a global population of minke whales (the whales most often targeted in their hunts) in excess of one million. To some this may make their kills of some hundreds of animals from this species seem more reasonable. However, despite repeated and continuing mentions of the minke whale, it is now accepted that there are at least two species (more likely three) and there are also subspecies and genetically distinct populations. So which of these population units should we be comparing removals by whaling operations with?
The situation of the minkes points to the reality of many oceanic whales and dolphins. The emphasis on species level conservation measures really does not work at all well for them. One population, although it may exhibit some distinctive behaviours or other characteristics, typically merges into another along a continuum. There may be anatomical differences between distant regions within the same species, but there may also still be interbreeding.
Take orcas for example. The various populations of orcas of the North Pacific live and feed in significantly differing ways and dont interbreed. Should they be treated as one unit for conservation purposes? Few people would say yes, but this is a case where differences are well documented. For many othermwhales and dolphins (especially those,living far from our eyes) we may not be able to discern that there are separate population units that need to be treated as such for conservation purposes.
How do you decide whether or not there is a discrete population unit? In terms of defining a species, amazingly there is no hard and fast rule! Historically species were defined on the basis of having differing anatomy and not inter-breeding (often prevented by physical boundaries like mountain ranges). These days a case for a new species is usually based on a study of the animals genetic code (its DNA ) to show that it is adequately distinct from other species, combined with something else that is special about this group.
This something else may be that the animals are geographically isolated, which works better with distinguishing land and riverine mammals than in the ocean, where barriers to movement are few, or a difference in anatomy and/or behaviour. Scientists wishing to propose a new species must wrap up all their evidence and present it in a formal scientific paper which is reviewed by other experts before it gets published. Once in print - and unless other scientists rush in with contrary opinions - it can usually be accepted that a new species has been identified.Beginnings and endings
But this process does not help us with sub-units of species that it may be important to conserve, and cases where it is less clear where a species begins and ends. The International Whaling Commission, in its attempts at achieving sustainable whaling, tends to focus on large sea areas where whales feed. These are usually highly productive waters where whales of the same species - but which breed in different places - may meet. So killing whales on the feeding grounds could inadvertently remove a population sub-unit that uses a particular breeding ground, and thereby lose genetic diversity (and potentially cultural diversity such as unique feeding specialisations or migratory knowledge passed from adults to offspring) unique to that sub-unit of the species.
Now, many readers will feel that every whale and dolphin is precious and should be protected, but this is not the thinking of any government and many influential organisations.
Typically they decide their priorities in terms of which are the most threatened species. So, this is an important issue and for the wide-ranging whales and dolphins it is especially perplexing. We need to start convincing people that smaller population units - sometimes not clearly defined - deserve action too. Certainly it should be increasingly clear that exterminating a species in a region (such as the porpoises in the Baltic) should be avoided at all costs, even if the population there is not proven to be genetically distinct. There are extra arguments for this, including those in favour of maintaining a healthy ecosystem which would require all the species that should be there to be present in robust populations.
Saving the whales ultimately means knowing them better, but conservation cannot wait on perfect knowledge of population subdivision or structure. We need to be very careful in all our actions around these animals and, of course, not buy into Japans argument that they are just the cockroaches of the sea. First published in WDCS Magazine, August 2008.
Authors: Mark Simmonds is a scientific consultant to WDC. Frank Cipriano is Research Professor at San Francisco State University.