On a possible hybrid between a fin whale and a blue whale
by Klaus Barthelmess
The following is a translation of an extract of an article I published in
Flemish in the Belgian periodical ³Marswin: Tijdschrift uitgegeven door de
Vlaamse Vereniging voor de Bestudering van de Zeezoogdieren² (ISSN
0771-1670), Vol. 8, No. 1, 1987, pp. 9-12. It is the earliest morphological
description of the first whale in which hybridism was later genetically
proven (Spilliaert & al 1991) and is supplied here because of its scientific
interest and the limited accessability of the article caused by its uncommon
language and the small run of published copies of the journal. PDFs of the
original Flemish article can be supplied by the author upon request.
In addition, there are now a few photographs available. They were taken by
me with a cheap camera and are of fairly poor quality, and hence were never
used. They were recently scanned from scratched slides, have been digitally
remastered and show the black baleen, the shape of the rostrum, of the
flipper, and of the huge dorsal fin, as well as detail of the pigmentation
pattern. These, too, are available upon request.
[The article opens with general remarks on my sojourn on the Icelandic
whaling station and the Icelandic research whaling program of the 1986
season].
³Whaling operations commenced on 16 June [1986] with two steam whale
catchers. Vessels reach the whaling ground, some 140 to 170 nautical miles
west of Iceland, after about 12 to 15 hours of steaming. Per whaling trip
catchers are permitted to bring in two fin whales or three sei whales or two
fin and one sei whale. Processing of the carcasses has to commence within 26
hours. From 07:00 to 23:00 hrs the whaling station makes radio contact with
the whale catchers in two-hour intervals, ia receiving intelligence about
all sightings of large whales. The whale species most commonly seen at the
beginning of the season was the humpback whale, followed by fin whales.
During the first ten days of the operations, blue whales were seen during
every third or fourth whaling trip, sometimes in proximity of fin whales.
Sei whales were not expected until the end of July.
On 22nd June [1986], at about 01:00 hrs, one of the whale catchers brought
in a whale, which upon closer examination on the flensing platform was found
to display [morphological] characteristics of both the fin whale and the
blue whale. It was a female of 70 feet (21.3 m) length.
The first general impression was that of a bulkier body than that of the
more ³slender² fin whales; the whalers rejoiced about a particularly ³fat²
whale. The shape of the head [rostrum] was slightly curved. The dorsal fin
was of an unusual, almost sword-like form and had a length of about 40 cm
[actually 56 cm], much unlike the small fins characteristic of blue whales.
The back had the grey-black colour typical of fin whales. The ventral side
was white, as were the undersides of the flippers. However, the colour
pattern was not asymmetrical as in fin whales, but largely symmetrical. Near
the navel, white pigmentation spots were visible on slate-grey ground, which
is a colour pattern normally characteristic of the entire underside of the
blue whale. The colour of all the baleen in situ, as well as the palate, was
black. However, the individual baleen slabs were thinner than with blue
whales, and when taken out, they displayed lengthwise striations of black
and lighter colour. Unfortunately both tympanic bullae (ear bones) could
only be retrieved broken. But even so it was apparent that they had a more
slender form that those of fin whales. Regrettably none of the biologists
present at the whaling station was in possession of an image of blue whale
bullae, but from my familiarity with 20th century whaler folk art I had the
vague idea that ³slender² ear bones came from blue whales.
These first osteological and morphological findings generated the impression
that this whale (No. 5 of the 1986 whaling season) could be a hybrid.
Strangely enough, the ovaries of this animal had corpora albicantia.
Accordingly, in the station journal this whale was recorded was ³fin whale
?² [with a question mark]. It is hoped that tissue samples collected by
biologists from the USA, Canada, Iceland, Spain and France will yield
interesting insights.
According to Dr. Paul Brodie (Fisheries and Oceans, Canada), one of the
scientists present at the whaling station, the question of hybridisation in
rorqual whales has been adressed several times in the past, but not
conclusively. During his own work at the whaling station in Nova Scotia,
Brodie noted several whales with similar characteristics. Also people at the
Icelandic whaling station remembered having seen one or two similar
specimens in the past.
During later research in the library of the Kendall Whaling Museum [Sharon,
Massachusetts] I came across a report that made it clear, that already in
the 1880s, for the shore whalers of northern Norway, the possibility of
hybridisation between blue and fin whales was not a question, but a
certainty:
³Nearly universally recognized among the Finwhalers is the so-called
³Bastard², from its having been supposed to be the offspring of mixed
parentage of a Blue and Common Rorqual. This variety appears to attain to
larger dimensions that the typical form [of the common or fin whale; KB],
and is described as grey, rather than the usual white, on the under side; on
one side the baleen plates are for a short distance at the anterior end
entirely white, while the remaining portions are darker than the normal
colour² (Cocks, 1887, p. 10).²
[the article closes with personal observations made during whaling].
Literature:
Cocks, Alfred Heneage: ³The Finwhale Fishery of 1886 on the Lappland Coast²,
in: The Zoologist, June 1887, pp. 1-16.
Update 2008:
This whale was later genetically established to be a hybrid:
Spilliaert, R., G. Vikingsson, Ú. Árnason, A. Pálsdottir, J. Sigurjónsson &
A. Arnason: ³Species hybridisation between a female blue whale (Balaenoptera
musculus) and a male fin whale (B. physalus): Molecular and morphological
documentation², in: Journal of Heredity, 82, 1991, pp. 269-274.
In later years, a total of five blue whale fin whale hybrids has been
ascertained genetically:
Bérubé, Martine, & Alex Aguilar: ³A new hybrid between a blue whale,
Balaenoptera musculus, and a fin whale, B. physalus: frequency and
implications of hybridisation², in: Marine Mammal Science, 14 (1), 1998, pp.
82-98.
Klaus Barthelmess
Whaling Research Project
Cologne
Germany
