Three strandings of whales have recently occurred on the north coast of Tasmania.

They involve a single pilot whale, Globicephala sp., amd two large schools of the

false killer whale, Pseudorca crassidens

Green, RH

Scott, EOG

Three strandings of whales have recently occurred on the north coast of Tasmania.They involve a single pilot whale, Globicephala sp., amd two large schools of the false killer whale, Pseudorca crassidens

EOG Scott (17076691)

RH Green (7750136)

The Francis Crick Institute

Recent whale strandings in northern Tasmania

University of Tasmania Open Access Repository

Papers and Proceedings of the Royal Society of Tasmania, Vol.l09, 1975 (ms. received 20.1.1975) RECENT WHALE STRANDINGS IN NORTHERN TASMANIA by E.O.G. Scott and R.H. Green (with three tables and two plates) ABSTRACT Three strandings of whales have recently occurred on the north coast of Tasmania. They involve a single pilot whale, Globicephala sp., amd two large schools of the false killer whale, Pseudorca crassidens. INTRODUCTION A stranding of a pilot whale (Globicephala sp.) was reported on 9.5.1973, and upon inspection by one of us (R.H.G.) the animal was found to be stranded head sea-wards at the high tide mark on rocks at the northern end of Greens Beach, northern Tasmania (plate 1). It was fresh and appeared to have died within the previous few days. The colour was uniform black. The dentition was 9 9 A series of measure-ments is given in table 1. 77. Upon dissection the uterus appeared empty, and the stomach contained only a small quantity of white seaweed-like rna terial. The head was removed for sub-sequent preparation of the skull, and within the nasal cavity there was found a considerable number of nematodes, later determined as Stenurus sp., probably S. globicephalae Baylis and Daubney, 1925. Specimens of the dolphin LagerzoY'hynchlAs acutus Gray, 1828 stranded on the coast of Massachusetts, U.S.A., in May 1973 were studied by members of the staff of the New Eng-land Aquarium in an endeavour to det-ermine a possible cause of the stranding. It was discovered the PLATE 1. - Pilot whale stranded at Greens Beach, May 1973. nasal cavity and the inner ear of these animals were infested with S. globicephalae (pers. com. Louis Garibaldi). No barnacles or other ectoparasites were observed in our specimen. If the view of Van Bree (1971) that within the genus Globicephala Lesson, 1828 only two species can be recognised, G. melaena (Traill 1809), and G. macrol'hynchus Gray, 1846, the animal here noted is referable to the latter. However, some authors are inclined to believe that of upwards of a score of other nominal species one or more may be valid, and it is clear that, in spite of some recent useful preparatory work, the taxonomy of the genus at present remains uncertain, particularly in respect of species and/or subspecies occurring in the southern hemisphere. The second stranding, that of the false ki1-1er whale (Pseudorea erassidens) (plate 2), reported in the daily newspapers of 12.6.1974, was of 170-172 false killer whales on Black River Beach, north western Tasmania, near Stanley. The animals probably came ashore the previous day. One of us (E.O.G.S.), with others, visited the 91 https://doi.org/10.26749/rstpp.109.9192 Whale Strandings in northern Tasmania TABLE 1 Measurements (cm) of a specimen of Globicephala cf. macpophynchus stranded at Greens Beach and 9 specimens of Pseudopca cpassidens stranded at Black River Beach, near Stanley. The index numbers and dimensions are after Norris (1962). (In the field small dimensions of Pseudopca measured in cm - eye, mm - larger dimensions to nearest inch). Index Feature Pilot False Killer No. r! r! r! t! r!- r! Cf 0 0 0 + + + 1 Length to fluke notch 344 236 244 302 381 467 480 384 401 404 2 Length to mid-eye 35 23 32 34 40 40 42 36 30 30 4 Length to gape 23 31 29 31 36 32 33 31 33 31 7 Gape to centre of eye 10 50 46 53 70 65 70 70 67 68 9 Length of head to blowhole 35 22 28 39 45 49 49 42 43 43 10 Length to pectoral 44 52 57 66 76 74 53 57 58 11 Length to tip of dorsal fin 165 127 133 163 196 239 252 194 192 191 13 Length to midpoint of genital slit 140 136 181 218 249 249 239 259 244 22 Max. girth at dorsal origin 132 137 165 208 257 239 224 239 220 24 Diameter of eye 2.5 3.0 2.7 2.3 3.2 3.6 3.3 2.7 3.1 3.1 26 Length of genital slit 26 10 7 11 13 13 30 2 2 3 27 Width of blowhole 7 40 45 29 Length of pectoral, anterior 52 31 36 43 56 58 70 45 54 56 30 Length of pectoral, posterior 50 29 34 41 54 56 68 43 52 54 31 Width of pectoral 16 11 13 14 19 23 24 17 19 20 31 Height of dorsal fin 26 15 23 23 32 40 38 30 . 32 31 33 Length of base of dorsal fin 51 41 61 69 89 96 102 66 81 78 34 Width of flukes 87 53 64 66 86 117 116 86 94 97 Dental complement 9 just 11 7 9 8 8 '1 erupt- 10 9 10 9 IT ing 93 E.D.G. Scott & R.H. Green site on 13-14.6.1974, and, under difficult conditions, collected some data before the animals were buried on the beach. PLATE 2. - False killer whales stranded at Black River Beach, June 1974. Most of the main mass, looking east. Photo: The Advocate. They were in two groups, the main mass extending over about 100 m, with a smaller compact group of nine lying some 400 m westward. When seen most were half buried in the sand at or near high tide mark, their orientation haphazard. The colour was wholly and uniformly black, save that in some individuals a sub-elliptical whitish or pearly area embraced the umbilicus, extending several centimetres in advance of it and beyond it. As table 1 shows, the range of the dental complement was 7-11 in both the upper and lower jaw. Length to caudal notch was recorded for 62 individuals, of which 34 were males, 20 females, sex determination being impracticable in 8 (table 2). Eighteen dimensions were noted for each of 6 males and 3 females (table 1). In October 26 females washed out from the mass grave were measured by one of us (R.H.G.): it is possible this series (table 3) included some animals measured in June. Tests of the significance of the difference from the male mean of June, October, pooled female means yield t = 2.898, 1.733, 2.939, respectively, the first and third being highly statistically significant (P better than 0.01), the second not being formally significant (P 0.1). The length distributions are tolerably symmetrical, the 94 Whale Strandings in northern Tasmania number of entries wi thin one standard deviation on either side of the mean (expected values with normal distribution in parentheses) being males 24 (23), June females 15 (14), October females 20 (18) pooled females 54 (51). TABLE 2 Length to caudal notch (cm) of 62 individuals (34 males, 20 females, 8 unsexed) of Pse:udorca crassidens, Black River Beach, near Stanley, measured June 1974; arranged in ascending order of magnitude (measurements in field to nearest inch) . Males Females Sex? 236 376 432 488 234 379 404 137 267 381 467 488 254 383 409 257 267 391 467 488 279 383 325 302 396 467 493 284 384 368 302 396 470 498 312 389 371 322 396 474 518 335 389 396 343 401 479 523 348 396 396 395 404 480 356 401 411 371 411 480 373 401 It was not feasible to undertake any internal examination. A search was made for barnacles and other ectoparasi tes, but none were seen. One very small individual, 137 em in length, probably not neonatal, was badly eaten by birds. On the morning of the second day a flock of about a dozen ravens, Corvus tasmanica Mathews, 1912, was flushed from the nine separate whales, which now appeared whitish, almost the whole of the skin having been stripped off. After an animal has been on the beach for a day or so, the integument can be peeled off in large pieces resembling sheets of black plastic. The third stranding was brought to the notice of one of us (E.O.G.S.) on 18.6.1974. It took place on the beach and adjacent flats on the west side of Perkins Island, about 10 km north west of Smithton, approximately 20 km westward from the stranding a week earlier. Mr Jeff Findlay, Health Inspector, Circular Head Municipality, Smithton, reported 43 whales were involved. They appeared to be of the same species as was stranded on Black River Beach,and were thought to have come ashore on the night of 14.6.1974. In view of the isolated character of the site, no attempt was made by the local authority to dispose of the carcases. Perkins Island was the site of a notable stranding in February 1911 (Lillie 1915, Scott 1942a) of a school of 38 individuals (all, or all but one, males) of the sperm whale, Physeter catodon Linne, 1758. The site of the Black River Beach stranding was revisited by one of us (R.B.G.) on 23.10.1974, when it was discovered that about 70 of the whales, buried there the previous June, had been washed from the sand and were scattered for about three miles (5 km) along the beach above high tide. With the assistance of Mr Terence Cashion, Queen Victoria Museum, and Sgt A. Archer, Smithton Police, five heads were taken for skulls and further measurements and other data call ected (table 3). Though over four months had elapsed since these whales had died decomposition was only slight, being most pronounced around the mouth. Sexing was a simple matter, males being readily recognisable by the prominently protruding penis. The abdomen of 26 females was opened in an endeavour to assess breeding condition. Four animals were found to be each carrying a single foetus, three belng males and one a female. Two foetuses were partly protruding from the genital slit, possibly because of abnormal pressures. 95 E.O.G. Scott & R.H. Green Three were in a head-first position and one was in a breech-birth position. The con-dition of the uterus in another 14 suggested recent parturition. Eight appeared to have not been pregnant in the present season (table 3). The head of one foetus has been preserved in formalin. Tooth wear in females was not as great as in the largest males, in some of which teeth were reduced to about half length. TABLE 3 Length to caudal notch, apparent breeding condition, and dentition of 26 female Pseudoroa arassidens washed from the sand four months after stranding at Black River Beach in June 1974. Individuals mayor may not be different from those listed in tables 1 and 2. Some comments on tooth wear are given. Length (cm) 277 293 296 337 349 360 361 367 368 380 380 385 386 390 395 396 400 405 405 406 406 411 425 428 452 480 Breeding condition empty empty enrpty empty post partum male foetus (134 cm) post partum female foetus (122 cm) empty post partum male foetus (140 cm) empty empty post partum post partum post partum empty post partum male foetus (163 cm) post partum post partum post partum post partum post partum post partum post partum subadul t subadult subadul t Teeth not worn (skull kept) not worn not worn (skull kept) not worn not worn slightly worn slightly worn (skull kept) slightly worn not worn not worn not worn It is of interest to note that in June 1936 a mass stranding of false killers, involving 90-100 individuals, occurred at Stanley, and the adjacent Walkers Island, only some 38 km westward from Black River Beach: measurements of some specimens made 96 Whale Strandings in northern Tasmania by one of us (E.O.G.S.) have been recorded by Pearson (1936, 188). Less than a year earlier (October 1935) the same locality had been the site of the coming ashore of a school of about 300 pilot whales (Scott 1942b), regarded by Davies (1960) as represent-ing a southern subspecies Globiocephala melaena edwardii Smith, 1834. Several large schools of this species have since died on Tasmanian coasts. Other local occurrences of Pseudoroa orassidens include one individual at Fanny's Bay, near Piper River heads in October 1957, and some 50 animals at Seal Bay, King Island in September 1958. Tasmania is, indeed, the type locality of the synonymic Orca meridionalis Flower, 1864, described two years after Reinhardt had reported Pseudoroa crassidens as living in the North Sea, Owen's original material having been found, sixteen years earlier, subfossil in a Lincolnshire fen, the species at that time being presumed to be extinct. This Society's journal for the 1919 session contains a paper (Scott & Lord 1920) on the osteology of a specimen of a false killer stated to have been one of a mixed school (including also Globicephala melaena and Orcinus orca) that came ashore at Adventure Bay last century. REFERENCES Davies, J.L., 1960: The southern form of Pilot Whale. J. Mamm., 41, 29-34. Lillie, D.G., 1915: Cetacea. Brit. Antarot. (Terra Nova) Exped. 1910, Zool., 1(3). Norris, K.S., 1961: Standardised methods of measuring and recording data on the small cetaceans. J. Mamm., 42, 471-476. Pearson, J., 1936: The Whales & Dolphins of Tasmania Part 1. External characters & habits. Pap. PrOD. R. Soc. Tasm., 1936 (1935), 163-192, text figs 1-15. Scott, E.O.G., 1942a: Records of Tasmanian Cetacea: No.1. Notes on various strandings at and near Stanley, north-western Tasmania. Reo. Queen Viot. MUs., 1(1), 27-49, pIs VIII-IX. ____ ~~~~~' 1942b: Records of Tasmanian Cetacea: No.2. A large school of the Pilot Whale, Globioephalus melas (Traill, 1809), stranded at Stanley, north-western Tasmania, in October, 1935. Reo. Queen Vict. Mus. 1(2), 1-34, pls I-XI. Scott, H.H. and Lord, C.E., 1920: Studies of Tasmanian Cetacea. Part II. Pap. Proc. R. Soo. Tasm., (1919), 1-17, pIs I-IX. Van Bree, P.J.H., 1971: On Globioephala sieboldii Gray, 1846, and other species of Pilot Whales (Notes on Cetacea, Delphinoidea III). Beaufortia, 19(249), 79-87, text figs 1-3. 

Recent whale strandings in northern Tasmania

Abstract

Similar works

Full text

Available Versions

The Francis Crick Institute

University of Tasmania Open Access Repository