The 1997 Airburst that killed 115 Cachalots (sperm whales)

1997, November 7. Southern Ocean. Midway between the South Island of New Zealand and Antarctica. Large Airburst. Time 07:46, (-57.3, 167.2). e = 8=, -e = 1.2 or an equivalent blast force of 1,900,000 kg/TNT.

1998, February 3 to 28. Tasmania. 115 Cachalots (97 female, 15 male, 3 unknown sex) were involved in three mass stranding events along the west and northwest coastlines. It should be noted that during (Stranding 1) thirty whales were seen offshore but never stranded.

Ocean Beach, Strahan (Stranding 1) On the evening of 3 February 1998, several cachalots were reported ashore on Ocean Beach near Strahan (42"18'S, 145'16'E). By the morning of 4 February, 66 animals had stranded, 12 of which were still alive. A rescue operation towed two animals (one male, one of unknown sex) offshore by midday, at which time two females and two males remained alive. By 0700 on 5 February, only one female and one male were alive. The female was euthanized and the male was refloated and towed offshore at 1630.

Greens Beach, Marrawah (Stranding 2)

At 0700 on 19 February 1998, local residents reported a group of cachalots in a tightly grouped formation off Greens Beach, Marrawah (40°55'S, 144'39'E). Shortly after 1000, they began to strand. By 0700 on 20 February only five of the 35 whales ashore were alive, with rough seas inhibiting any chance of rescue. At 1300 one male and one female were alive. By 0900 on 21 February, the female had died and at 11:00 the male was euthanized.

Black River Beach, Stanley (Stranding 3)

At 1000 on 28 February 1998, 11 Cachalots were reported ashore at Black River Beach, Stanley (40'50’S, 145’17’E). At 1230, 10 females were found deceased and one male alive. At 0400 on 1 March the male sperm whale was towed offshore, but later re-stranded at Edgecumbe Beach (40’52’S, 145’25’E), 10 km east at 1600. This animal was positively identified from Black River Beach by the presence of a lower jaw deformity. At 0230 on 2 March, the whale was towed offshore again and was followed for approximately 14 km, after which it was observed to swim away.

Therefore, 66 of these cachalots were stranded at Ocean Beach, Strahan; 35 at Greens Beach, Marrawah; and 11 at Black River Beach, Stanley. The remaining whales stranded singly along the coastline. Three mass strandings of this species in such close temporal proximity have not been reported in this area before, and this is the first time that data have been comprehensively collected from complete or near‐complete groups of sperm whales from Tasmanian waters. Adult females dominated the three stranding groups. Total lengths ranged from 417 to 1,200 cm and ages ranged from 0.75 to 64 years. Four females were lactating, and four fetuses were found among the groups. Stomach contents were dominated by pelagic cephalopods.