Wednesday, November 18, 2015

Great Whale Gatherings - Part 3

Part 3: The Sperm Whale, the only Great Whale of the Toothed Whales

In the first section of this multi-part article, I posed the question of where the greatest gatherings of great whales occur and discussed various candidates amongst the baleen whales. Familiar whales such as the Blue Whale which feed by filtering water through baleen plates in their mouth are known as baleen whales. In this section of the article, I explore the subject of large gatherings which are reported for the Sperm Whale, the only toothed whale large enough to be classified amongst the great whales. In the first section of this article, I concluded that the greatest gatherings of great whales must be that of the Grey Whales gathering in breeding lagoons in North America. However, I also noted that as the whales are spread out, in terms of a visual spectacle, a super-pod of Sperm Whales, may be more spectacular. Sperm Whale are truly social animals, the elephants of the sea. However, encountering a super-pod is a matter of chance and in this second section of this article, I pick up their story.

Sperm Whales

In the Sunday Times (Sri Lanka) on 5th August 2012 I published the claim that Sri Lanka offers the best chance of seeing a super-pod (defined as more than 40 individuals) of Sperm Whales on a commercial whale watch. It leads to the bigger and more important claim that one of the biggest, recurrent, contemporary gatherings of great whales occurs off Sri Lanka. The large gathering of Sperm Whales off Sri Lanka has not been recorded annually. But super-pods numbering over 40 individuals have just about been recorded each year since 2009. The large gatherings of over 250 Sperm Whales may not occur each year, or it may only last a few days each year and may be missed by the absence of observers. It will be hard to verify its annual occurrence unless more seasoned and attuned observers are out in the water or there is programme of aerial surveillance. I say ‘attuned’ because most local naturalists had failed to recognise the international significance of these super-pods and some records may have been ‘lost’ if it were not for conversation with me. Although large super-pods exceeding 100 Sperm Whales have been recorded in Mirissa in the South and Kalpitiya in the North-west, so far the large gatherings of over 250 Sperm Whales in a concentrated area have only been observed in Trincomalee in the Northeast of the island. The counts I refer to are only on surface counts as is the norm when reporting counts of whales.
These gatherings are probably the greatest ever known for Sperm Whales except for two previous observations published in 1839 and in 1946. In a letter to the editor of Natural History (55:96), W.D. Boyer, referred to an observation on 28th August 1945 off Peru at approximately 6 degrees South and 82 degrees West, near the Galapagos. This letter is also quoted in the prologue of Hal Whitehead’s book ‘Sperm Whales: Social Evolution in the Ocean’. It states ‘....approximately 400 to 600 whales were to be seen at one time from the centre of the school and it can be safely assumed that the entire school consisted of well over 1,000 whales.’ The February 1946 issue of Natural
History also carried a comment to Boyer’s letter by George G. Goodwin of the American Museum’s Department of Mammals. Excerpts from his comments include ‘.... In recent years 30 or 40 of them would be considered an exceptionally large school of them…’ and ‘ .... Thomas Beale stated in his Natural History of the Sperm Whale (1839) that he had one school of as many as five hundred or six hundred. The log books of whaling ships, so as far as I can learn, give no such stupendous figure.’ Unfortunately, Beale provides no details in Chapter VI on ‘Herding, and other particulars, of the Sperm Whale’, in his book merely stating that ‘I have seen in one school as many as five or six hundred’. R. A. J. W. Lever writing in the South Pacific Bulletin in 1954 in his article ‘Whales and Whaling in the Western Pacific’ states that ‘In the early whaling days, schools or ‘pods’ numbered up to 100, but extensive hunting in which nursing mothers and young were not spared, so reduced this figure to about 15’.
Hal Whitehead and his team of researchers have been studying whales in the Eastern Pacific near the Galapagos. There are no contemporary accounts of such large gatherings of Sperm Whales. In a conversation I had with Hal Whitehead in London on 29th August 2013, he told me that his research team has seen pods of Sperm Whales of 50-100. In an email to me on 15th April 2015, he commented ‘I would note that there is a very good reason why there have not been enormous groups seen in the eastern tropical Pacific since Boyer's day. His observation was just before massive and largely unregulated whaling in the region (ca. 1948-1982’).
Continues the 12 th of November...

Gehan de Silva Wijeyeratne
05 November, 2015