AN ANALYSIS OF FOUR LARGE ACCUMULATIONSOF SPERM WHALES OBSERVEDIN THE MODERN WHALING ERAROBERT A. PATERSON*ABSTRACT

The phenomenon of large accumulations of sperm whales has beenreported only occasionally in the modern whaling era. This paper details
four such observations and it is suggested that the available evidence does
not strongly support the previously advanced explanations viz. that theaccumulations are due to migrations towards feeding or breeding grounds
or are the result of social disruption arising from whaling operations.

INTRODUCTION .

The occasional occurrence of large numbers of sperm whales was reported byopen-boat whalers in the sailing era and was termed "making a passage" (Bennett,1840; Bullen, 1902). Colnett (1798) considered that sperm whales, observed"making a passage" towards the Galapagos, were going there to breed. This
paper discusses four sightings of large numbers of sperm whales made in thiscentury. In view of the relative rarity of such reports it is considered opportune
to detail them in full.
REPORTS

Tomilin (1936) noted that he had received a report from Otto Kraul who, in
1912-13 between latitudes 42°-50°5 off the Patagonian coast, encountered acolossal herd of sperm whales. They numbered 3,000-4,000, were of both
sexes and included calves and juveniles. Kraul, who said this herd was thelargest he had ever seen, had extensive whaling experience both as a gunnerand expedition manager in both hemispheres and was one of the founders ofmodern German whaling (T0nnessen and Johnsen, 1982).
The following letter, from William D. Boyer, the third officer of thesteamer Daulton Mann, was published in Natural History (Boyer, 1946):
During a recent voyage along the west coast of South America this vessel
encountered an unusually large school of sperm whales. They seemed to* P. 0. Box 397, Indooroopilly, Qyeensland, Australia, 4068.
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PATERSONbe, as far as we could determine, in some sort of mass migration. At thesuggestion of the ship's Captain, who has sailed this coast for many years
and has seen nothing that could compare with this, I shall describe what weobserved.
On the morning of August 28, 1945, we were northbound off Aguja
Cape, Peru approximately 6°S, 82°W. Shortly before 9.00 a.m. individual
groups of from two to six sperm whales were seen dotting the visible surfaceof the ocean. They were all travelling south. A short while later the numberof groups increased until the entire ocean, to all visible limits of the horizon,
seemed spotted with them. The sum total was a school of gigantic proportions- all headed south. It took the vessel nearly an hour to travel through themain body of the school, and the ship was proceeding north at full speed.
Several times a collision with a whale was narrowly averted, as they apparently
held little fear of the ship and as often as not would stay on the surface
rather than sound. This afforded close inspection and positive identificationof the whales.
During the remainder of the morning small groups or single straggling
whales were seen, the last of them being sighted shortly after noon. It is
impossible to estimate the number of whales in the school, because the eastand west limits could not be ascertained. However, approximately 400 to
600 whales were to be seen at one time from the centre of the school and it
can safely be assumed that the entire school consisted of well over 1,000 whales.
I hope that this information may be of interest to you.
I might add that among all the professional seamen aboard, no one had
ever seen a similar sight.
During whaling operations off Durban, South Africa in July 1972 aerial
searchers reported:
A most unusual trek of sperm whales was encountered on the 29th of
this month. At 0650 that day, two big sperm were found by W26. Searching
to the east of the catchers chasing, the aircraft at 0735 found 14 medium
sized sperm 15 miles from the catchers, at 105 degrees from Cooper light,
60 miles. Minutes later, the aircraft saw three big sperm 5 miles south ofthat position. After directing the catchers, the aircraft began a systematic
search in the vicinity and soon found three flocks of small sperm. All thewhales were trekking between 020 and 045 degrees at speed.
During the following two hours, the aircraft found sperm all along a line
running almost parallel to the shelf and extending 40 nautical miles fromthe position of the aircraft sighting at 0735. This fantastic line of whales
comprised 19 separate sightings, with some of the small sperm herds consistingof over 50 whales. In nearly. every large flock there were from one to three
big bulls, while most flocks included cows with calves.
Our estimate of the total number of whales in this trek is 600, of which
100 were considered to be under catchable size. These figures have been
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LARGE ACCUMULATION OF SPERM WHALESTABLE 1. COMPARATIVE DETAILS OF THE FOUR SPERM WHALE SIGHTINGS
Location
DateLunar phase

Patagonia
1912-13
Unknown

Observation method
Effect of observation
method on whale
behaviour
Relati~n to whaling
operat10ns
Directional
uniformity
Estimated numbers

Ship

Aguja Cape
28 August 1945
5 days after
full moon
Ship

Durban29July 1972
3 days after
full moon
AerialTasman Sea
25 February 1978
2 days after
full moonShip

Not recorded

None

None

None

Unknown

No

Yes

No

Not recorded

Yes

Yes

3,000-4,000

1,000600-700

Yes (withexception ofone individual)
Not estimatedconfirmed by the catch Leader. In this connection, we feel it is relevant todraw attention to the fact that on many occasions up to 20 percent morewhales than the number sighted by the aircraft come to the surface when
the catchers reach the whales and start chasing. This applies particularly toherds of small sperm, so that the estimated 600 whales seen on the 29th
could represent an actual total of over 700.
Peter S. Cosgrave a marine engineer of Sydney, Australia observed a large
concentration of sperm whales in the Tasman Sea and his sighting was reportedby Paterson ( 1981):
I was bringing a 60 foot twin-diesel vessel from New Zealand to Sydney.
On the morning of 25 February 1978, in calm, clear conditions which gave
perfect visibility, we sighted whales spouting from horizon to horizon. Distanceof observation varied from 10 feet to the horizon and all but one appeared
north-bound. The ones closest to us appeared to be mostly in the 25-35 feet
range, their colour was a light mid-grey with the dorsal fin somewhat aft ofamidships. We continued crossing this stream of whales for the greater partof the day and while I did not time this precisely it covered a period of someseven to eight hours.
Our course was from east to west and our position by observation was36°S, 156°E. The sighting continued until after we had passed 155°E,indicating that the stream was some 70 miles in width. This position, as you
will observe on a chart, is approximately 240-250 miles east of Jervis Bay.
I have spent a good deal of time at sea around the world and never before
or since have I seen such a concentration of whales. I could not attempt toestimate the numbers; while naturally they were not packed like cattle in ayard, I can only say that at any time one chose to make a 360° sweep one
would sight 10 to 18 spouts simultaneously.
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PATERSONIn each report, irrespective of the observer's occupation, the impression
is conveyed that the sightings were a dramatic event. The sightings were widely
separated in time and before discussing their possible significance it is useful
to tabulate the comparative data (Table 1).
DISCUSSION

Reports of large accumulations of sperm whales, detailed by Caldwell
Caldwell and Rice, (1966) have been relatively uncommon given the world-wide
extent of sperm whaling in the last two hundred years. It is possible that detailsof such sightings have been recorded, but not published. In that regard, it isof note that two of the four reports listed above came from mariners unassociatedwith the whaling industry. The numerical estimates of open-boat whalers may
have been limited because of their pre-occupation with whaling operations orattempts thereat in vessels whose courses were dictated in part by prevailingwinds.
In samples of 766 and 1,397 schools of sperm whales, the maximum
school sizes reported were 120 (Ohsumi, 1971) and 200 (Gambell, 1972)
respectively, w4ile Best (1979) noted that sightings on whaling grounds ofschool sizes in excess of 100 had become uncommon. It is necessary to consider
if the large numbers in the four sightings in this paper represented an
unusual aggregation of normal schools or the formation of a super-school,with loss of normal social organization. The sighting reports will be examined
to see if they match earlier suggestions that such events were due to massmigration associated with breeding or feeding or to disruption of normal socialgroupings because of whaling operations.
The Durban sighting, recorded by aerial observers cooperating with whalechasers, is understandably the most detailed with regard to school composition.
It appears that there was an accumulation of normal sized schools rather than
the formation of a super-school. Comments by the observers such as "a mostunusual trek" and "fantastic line of whales" suggest that the events were notthose expected during whaling operations, even though sperm whales had
been caught off Durban since 1912 and the spotter company had been
operating there since 1954. There is no indication if the sighting off thePatagonian coast was associated with whaling operations but those off Aguja
Cape and in the Tasman Sea were not. However, large catches of sperm
whales, including almost 15,000 animals by pelagic fleets (Garrett, 1980), hadbeen taken off the coast of Peru from 1936 to 1943. Nevertheless, the rarityof such sightings suggests that even if social disruption is the cause, its effects
could only be short-lived.
The sightings occurred within latitudes where nursery and harem schools(Ohsumi, 1971) could be expected, although the three dated records occurred
outside the peak of the breeding season (October to December) in the southernhemisphere (Best, Canham and Macleod, 1984). It is unlikely therefore that
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171

the whales were massed for the purpose of migration to a breeding ground.
Details of the observation time off the Patagonian coast are lacking but thewhales in the other reports were observed for some hours only and theirdestinations were not determined.
Holm and J onsgard ( 1959) analysed the extensive data available from
Norwegian sperm whaling operations in Antarctic waters and noted thatcatches were greatest near oceanic banks at the phases of new and full moonwhen greater amounts of squid may have been available. Catches were lowest
in the period of the waning moon. A daily catch was considered to be large
if 30-40 whales were taken and there was no report of large schools seen by
the Norwegians in Antarctic waters during the years 1950-1956.
In the three reports of known date in the present study the observations
were made at intervals of two, three and five days after the day of full moon.
(The phases of new and full moon comprise seven days, three days before themoon is new or full, the day of new or full moon and three days after.) The
steady, uni-directional movement of the whales during the periods of observationsuggests that they were not likely to be engaged in feeding.
ACKNOWLEDGEMENTS

Dr P.B. Best has been most helpful with his advice and has kindly allowed
publication of the report from Rennies Oceanic Pty Ltd of the Durban sighting.
Mr P.S. Cosgrave patiently answered my questions in relation to the Tasman
Sea sighting. Ms L. Macfarlane of the Old Royal Observatory, London provided
the information concerning lunar phases and Mrs N. Murarenko translated
from Russian the report from the Patagonian coast.
REFERENCES
BENNETT, F. D., 1840. Narrative of a· whaling voyage around the globe from the years 1833 to 1836. Richard
Bentley, London, 2 Vols.
BEST, P.B., 1979. Social organisation in sperm whales, Physeter macrocephalus. pp. 227-289. Jn: H.E. Winnand B.L. Olla (ed) Behaviour of marine animals, Vol.3. Plenum Press, New York. 438 pp.
BEST, P. B., P.A. S. CANHAM, and N. MACLEOD, 1984. Patterns of reproduction in sperm whales, Physeter
macrocephalus. Rep. int. Whal. Commn (Special issue 6): 51-79.
BOYER, W. D., 1946. Letter to the editor. Nat. Hist., 55: 96.
BULLEN, F. T., 1902. The cruise of the Cachalot. Macmillan, London.. 379 pp.
CALDWELL, D. K., M. C. CALDWELL and D. W., RICE, 1966. Behaviour of the sperm whale, Physeter catodon L.
pp. 677-717. Jn: K.S. Norris (ed.) Whales dolphins and porpoises. University of California Press, Berkeley.
789 pp.
CoLNETT, J., 1798. A voyage to the South Atlantic and round Cape Hom into the Pacific Ocean for the purposeof extending the Spermacettz' Whale Fisheries and other objects of commerce, by Captain James Colnett of theRoyal Navy, in the ship Rattler. W. Bennett, London.
GAMBELL, R., 1972. Sperm whales off Durban. Discovery Rep., 35: 199-358.
GARRETT, T ., 1980. Pelagic whaling off the 'Coast of Peru' 1936-1954. Statistical material compiled by T.
Garrett. Rep. int. Whal. Commn (Special issue 2): 134-136.

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PATERSON

HOLM, J.L., and E. ]ONSGARD, 1959. Occurrence of the sperm whale in the antarctic and the possible influence ofthe moon. Norsk Hvaifangst-Tid., 48: 161-182.
0HSUMI, S., 1971. Some investigations on the school structure of sperm whale. Sci. Rep. Whales Res. Inst., 23: 1-25.
PATERSON, R., 1981. 'Whale watch' brings encouraging reports. Aust. Fish., 40 (4): 30-33.
ToMILIN, A.G., 1936. Cachalots of Kamchatka Sea. Zool. Zhur., 15: 483-519.
T0NNESSEN, J.N., and A.O. JOHNSEN, 1982. The history of modern whaling. Hurst and ANUP, London andCanberra. 798 pp.

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