David @ Tokyo

Don't pander to hysteria over whale calf's death, say scientists

Some Australians have apparently been quite upset about a decision made by professionals to put down a humpback whale calf, which had been named Colin until people later realised that the whale was of the female sex.

The whale was apparently without it's mother (which may have already died), and no specialists seem to think Coleen had a chance of surviving under the circumstances.

While there are also questions over whether the most appropriate method to put the whale down was used, it's the decision to put the whale down at all that seems to have been drawing most criticism from some in Australia.

Cetacean experts of both Australia and New Zealand have been speaking out against the criticism. Here are some of the quotes from the linked article:

"People have to accept a lot of whale calves will die in the wild, and it's not pleasant, and there is nothing that can be done".

"This isn't a cute and cuddly world and people have to think about the reality of wild animals."

"I don't think we should be moving towards doing things to keep animals alive in cruel circumstances just to make us feel good".

Young animals fresh into the world are naturally prone to high rates of natural mortality, and without a mother to take care of them they are without food and thus almost certainly a goner.

For several years we've been hearing about booming rates of growth in the populations of humpback whales that migrate up the east and west coasts of Australia each year (even the IUCN has taken them off their "Red List" of endangered species). With these increasing numbers of animals you not only have a higher probability of humans seeing whales along the coast (whale watching), you're also going to see increasing instances of whale deaths along the coast as well. Furthermore, at some stage the populations will increase to the point where they reach and exceed the capacity of their environment to support their numbers. Exactly what happens at that point in time remains to be seen, but one explanation in other places is that you end up with a lot of whales in poor health and observe sudden die offs, or unusual mortality events.

Australian scientists seem to have a preference for talking down the current levels of abundance, and it's true that they are unlikely to be at their carrying capacity yet, but they are approaching it quite quickly.

I've long been thinking that it will be interesting to see what changes in the Australian mindset come about as these whale numbers continue to increase, and the realities of nature are observed more amongst the urbanites living along the East coast of Australia. This incident is very unlikely to be the last like it. Particularly, whether any change in the prevailing attitude towards the acceptability of sustainable whaling occurs in the coming years will be worth watching. Commercial anti-whaling industry groups will be doing their best to ensure that this isn't the case, but with an increasing recognition that some whales species are not threatened with extinction and can support sustainable whaling, they will find themselves facing a steeper uphill battle, but still there would be few in Australia to assert that the protectionist stance be replaced with a more conservationist one.

Labels: humpbacks, unusual mortality event

As in various other parts of the world, the humpback whale appears to be in relatively healthy shape in the North Atlantic.

In 2002, at the IWC Scientific Committee had this to say:

In conclusion, the Committee agrees that it has greatly increased its knowledge of North Atlantic humpback whales as a result of its Comprehensive Assessment. In particular, populations are increasing in a number of areas in the North Atlantic (Gulf of Maine, Iceland, West Indies) and the rate of increase of the West Indies breeding population is estimated at 3% per annum between 1979 and 1992 (IWC, 2002l, p.236). This breeding population has an estimated population size of 10,752 in 1992 (IWC, 2002m, p.258).

However,

the Committee is unable to provide advice on the population level of North Atlantic humpback whales in relation to carrying capacity. This statement applies to past carrying capacity and to present carrying capacity.

In another document, Philip Hammond, Peter Stevick and others add that:

We estimate that this population has been increasing about 3.1% a year over the 14-year period. This growth rate is lower than we know it could be, which may mean the population is approaching the size it was before hunting began.

With that background, I was interested to see news today that the National Oceanographic and Atmospheric Administration has observed a "sharp increase in humpback deaths since last summer". Apparently scientists have been able to access one dead female whale

The dead whale is a huge find ... this is the first stranded leviathan from which they can get fresh biological samples, NOAA Fisheries spokeswoman Terri Friday said.

''We don't get a lot of opportunities to sample, so necropsies are very important,'' she told Florida Today.

Such samples can provide a life history of the animal, its food habits, illnesses and viruses that might compromise the rest of the population, the presence of biotoxins or injuries that indicate a cause of death, she said.

With only a single sample to go on I wonder whether the biological samples answer more questions than they pose.

However, in seeing this I recall the observation of an "unusual mortality event" in the essentially fully recovered eastern gray whale stock, which resides off the west coast of North America. From the discussion of the report:

Taken together, these events could be indicative of a population near carrying capacity that experienced substantial nutritional stress during poor environmental conditions, which was translated into lower reproduction and higher mortality. Although these effects have been seen only in recent years, a new analysis fitting a density-dependent model to the population-trend data suggests the Eastern North Pacific gray whale population is no longer increasing and has been relatively stable since the late 1980s or early 1990s; therefore, it may be close to or already at carrying capacity (Wade 2002).

Perhaps the North Atlantic humpback whale too has hit it's carrying capacity? I'm sure they will be a lot of scientific interest in this situation.

UPDATE 2007/01/18:
Another humpback death has been reported.

Labels: gray whale, humpbacks, unusual mortality event