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