George Cook, and his son, Mr. From the whaling lookout at the entrance to Tory Channel it is sometimes possible to observe humpbacks travelling around the edge of muddy water and even following the projections and indentations closely without entering any tongues of muddy water. Thus, although it is certain that there is no consistent relationship between ocean currents and the major movements of humpbacks, the possibility that some of the smaller deviations from certain regions of the coast are locally modified by currents and tidal streams must be considered. Surveys are currently being conducted off the New Jersey coastline in order to determine where whales are located, how many individuals are there, and during what time of year. The great difference in rate between 4—5 knots and little more than 1 knot in the overall rate of advance described above, indicates that there are frequently periods of rest and random movements on quite a large scale in the course of their main migratory route. The whales are not, however, seen regularly in these waters after the end of November.
Cause of sperm whale strandings is still unclear
Toms, of Pauahatanui, while those for to have been provided by Mr. During December there is usually a substantial decrease in daily sightings, although in more than were reported before December 14, which was the latest date for humpback sightings in that season. The localised humpback concentrations reported at months other than those in which the north and south migrations normally occur, were each associated with local concentrations of food organisms. Nevertheless there is no evidence that humpbacks are more evenly distributed over the general oceanic expanse of the South Pacific than occurs in the Indian and South Atlantic Oceans. Sperm whales are born into a matriarchal social unit. Other threats include entanglement in fishing gear, collisions with ships, and proposals to allow for a commercial hunt once again. Some humpbacks follow the coast so closely that they pass Ninepins Island on the western side of the Bay of Islands, and whaling was carried out from this site for a number of spring seasons in the early 's.
Transactions of the Royal Society of New Zealand Volume 84 [electronic resource]
Within days, the corpses decay significantly and might even explode as a result of gases that increase the inner body pressure. Temperature shifts in seawater might be the root cause; as such changes can alter the migration pattern among prey populations, attracting the sperm whales into the North Sea. Most distinctively however, are the unusually long, often white, pectoral fins, in stark contrast against the almost black upper body. For these years the humpback catch totalled , with an average of 48 per season, and the catch of other species was negligible. In most places where Sperm whales are known to live, it is not uncommon to be able to observe year-round quite large groups of immature males sticking together, the group size decreasing as the youngsters grow and reach maturity. Stipple indicates the main areas where humpbacks are inferred to approach or leave the coastal waters.
The decreasing incidence of sightings south of East Cape and scarcity of them along the east coast of the South Island certainly indicates that the majority of the whales travelling between North Cape and East Cape do not follow the coast closely once past the latter point. In other parts of the South Pacific Ocean, it is now clear from many observations, that humpbacks in substantial numbers pass certain island groups spaced over at least the 3, miles between East Australia and the Cook Islands and possibly further to the east. This has been confirmed by a sighting total of in Cook Strait during From Kaikoura for some distance northwards towards Cape Campbell there are frequent reports from observers on coastal shipping, fishing vessels and aircraft, and nearly all the reports are of whales within a mile or so of the general trend of the coast. The number of humpbacks caught from Whangamumu per season between and is shown in Table I. Very helpful co-operation from the Royal New Zealand Air Force provided some opportunities to investigate this question by taking the writer and another observer B.