Tuatara: Volume 1, Issue 3, September 1948
Biological Interests at a Whaling Station
Biological Interests at a Whaling Station
A whaling station is a place that appeals to the imagination of most people. Much of the interest is due to the enormous size of whales as compared with other mammals and the many adaptations for aquatic existence shown by whales. Probably some of the interest to New Zealanders is due to the large part whaling played in the early history of this country. Today, the only whaling station still operating in New Zealand, is that owned by Messrs. Perano at Te Awaiti, in Tory Channel, 18 miles from Picton.
From below a lookout not far from the station, the three chasers go out and make most of their catches in the Cook Strait area which is under observation by those watching for the whales from the lookout. There is an excellent account by Ommanney (1933) describing the methods used for catching whales in New Zealand from the early days of Bay whaling, to the modern type of fast motor launch chaser used by Messrs. Perano. After the whale is killed and inflated with air by the chaser, the mother ship, Tuatea, makes fast to the whale and tows it into the bay where the factory is situated.
The species of whale usually captured is the humpback (Megaptera nodosa). Its slow movements and habit of following regular coastal migration routes make it relatively easy to catch with modern facilities. After the general use of the explosive harpoon, which was first used on a large scale in the southern hemisphere by Norwegian whalers in 1904, the captures of humpbacks greatly increased. During the 1912 season over 10,000 humpbacks were taken from the Falkland Islands and South Georgia region alone. With the later extension of fast steam chasers and floating factory ships into the far south, the larger and faster blue and finback whales formed the main part of the total catch. Nevertheless 8,000 humpbacks were included in the total world catch as recently as 1937. By this time the effect of continuous overkilling was sufficiently alarming to produce a number of restrictions which give some protection to the humpbacks. In a series of International Conventions the areas in which floating factory ships could operate were determined. The humpback is now caught mainly by chasers operating from shore stations such as that at Tory Channel, and the number which can be captured in this way is far less than the totals taken formerly. It is the chase and operations on board ship or factory that are described most frequently in general accounts and books on whaling, but for a biologist there are many other items of interest which may be studied during whaling activities.
Explanation of plate. Photo of humpback whale showing the knobbly appearance, huge flippers, and grooves on the underside. Barnacles are visible on the knobs of the lower flipper but most of those under the chin are covered by the whale. Note the eye at the angle between the upper and the protruding lower jaw.
Along the under surface of the throat, there are about 24 long grooves which extend from the chin to well behind the flippers. In photos of humpback whales these grooves are very frequently taken to be a series of cuts presumably made for removing the blubber. The grooves serve to give elasticity to the floor of the mouth and to increase the mouth capacity for the intake of great volumes of sea water containing the small organisms which are strained out by the whalebone during feeding.
The whalebone itself is arranged in a series of plates about half an inch apart and placed at right angles to the jaw. There are 3-400 along each side arranged like the leaves of a book. The largest in the humpback whale are about 22 inches long and 9 inches wide at the base, from which they taper to a point, resulting in a triangular shape. Along the inner edge, each is frayed out to form a series of bristles resembling very coarse hair. The bristles from each plate become entangled with those from adjacent plates resulting in a coarse matted inner surface from the tip of the baleen up to the very narrow palate. This mat acts as a very efficient sieve. Evidence of its effectiveness has been found at Perano's station, where many gallons of food matter composed entirely of crustacea each less than half-aninch long has been found. This is considerably smaller than Munida (1 to 2 inches long) which forms the whalefeed in the Subantarctic waters, or the Euphasian krill (about 2 inches long) which provides the bulk of the food material for baleen whales in Antarctic waters.
Although the eyes are of large size (4 inches diameter) they appear very small in relation to the total size of the animal and are situated well back in the head just above the angle of the jaws. The nostrils, as in all whales, are situatedson the top of the head and have merged to form the blowhole.
There is no external ear, but a small slit like aperture marks the external ear opening. From this a narrow tube passes through the blubber, and near the under-side of the skull a tube can again be found, but with a considerably wider bore as it approaches the internal ear. If one attempts to follow out the type of communication between these two sections of tube, it soon becomes apparent that they are quite unconnected. There is a mass of completely closed tissue in the region where one would expect to find a continuous tube connecting page 17 the outer with inner portions of the existing tubes. This finding was first made by Lillie (1915) and immediately raised the question as to how whales hear. It has been suggested that sound vibrations are received through the mouth and pharynx, but inspection of the whale's head shows a 12 inch mass of spongy tissue between the pharynx and internal ear. This should be a very effective barrier to sound vibrations. Lillie has shown that the only communication between the internal ear and external environment is from the tympanic cavity through the tube communicating with the nasal passages (position of the Eustachian tube in whales) to the column of air in the blowhole. The latter is closed under water by elastic lids, but sound waves in the water impinging on the lid could possibly be transmitted through the column of air. These waves could then reach the tympanic bulia which acts as a sounding box, and travel from here by the ear ossicles to the membrane (fenestra ovalis) of the inner ear. He suggests that the only possible way of hearing is through this channel. Hearing through a blowhole would certainly be a unique arrangement, but no other method has been demonstrated and whale behaviour seems to show that they certainly can hear. The question is quite unsettled, and presents a very intriguing problem to biologists.
The exposure of the internal organs for removing the fat is probably the most interesting moment of the factory work for a zoologist. It conveys an impression of the enormous size of whales which is even more striking than seeing the complete whale at close quarters for the first time. Most people are familiar with the fact that whalebone whales range up to nearly 100 feet in length, but tend to overlook the fact that the internal organs must reach a proportional size. The heart in a 40 foot humpback whale is 5-6 feet long, and the dorsal aorta, is over 2 feet in circumference near the heart. In the gut, the intestine alone is over 200 feet long, and the liver weighs from 6-7 cwt. Most of the other organs are proportionately large, the main exception being the brain. Its circumference of 2 feet is so small that the dissected brain can almost be fitted inside the base of the whale's main blood vessel. The brain is much shortened being only 9 inches long, so it occupies only a very small portion of the skull which reaches 15 feet in length.
The internal organs show many close structural resemblances to those of land mammals, although a comparison of external appearances shows so many differences. The stomach, however, is complex and contains even more compartments than that of the cow or sheep. The kidneys are compound, each being composed of a large number of small kidneys or reniculi which are connected together by collecting ducts and connective tissue. It is only during the examination of internal structures that the vestigial pelvic bones and hind limbs can be seen. Two boomerang shaped bones 18 inches long are the only page 18 traces of the pelvic girdle and these bones are embedded in the ventral body wall. Attached to the angle of each in the humpback whale, there is a small knob of cartilage which is described as the femur and is the only remnant of the hind limb. There has, however, been one specimen of humpback whale described (Andrews, 1921) which had much more completely developed hind limbs extending 4 feet 2 inches outside the body, and containing bones identified as tibia, tarsus and metatarsal, in addition to the femur. As external rudimentary hind limbs have been described in early embryos of the humpback whale, this example of hind limbs in the adult has been interpreted as the result of the persistence and continued growth of the embryonic rudiments until the adult stage was reached.
In addition to the whales there are a number of associated organisms which present problems of interest that can be studied at a whaling station. On the skin of the whale, there are more barnacles than can be found on the hulls of most ships. The whale barnacles belong to different species from those found on ships, the commonest on the humpback whale being the sessile barnacle Coronula diadema which is 2 inches across and 1 ½ inches high. These are very firmly attached to the whale skin which projects into furrows on the under side of the barnacle. Before the whale is cut for flensing the barnacles have to be removed to avoid any chance of knives being damaged by their hard shell, and the use of considerable force with triangular headed iron bars is often required to pull them off. Their distribution is remarkably constant on each whale. The main patch is immediately under the chin where more than a hundred Coronula may be attached. Most callosities have a number attached and each of those along the anterior margin of the flippers usually carry several specimens, and some are found along the anterior edge of the tail flukes. The rest of the body, especially the upper surface is almost free from Coronula. Most of the Coronula have up to a dozen specimens of the stalked barnacle Conchoderma auritum attached. The latter grow to 3 or 4 inches long and hang like tassels from the Coronula, especially from those under the chin.
Among these barnacle masses, numerous whale lice about half an inch long can be found adhering very firmly by their sickle shaped claws. These are flattened amphipods which can be found singly or in groups over most of the ventral surface of the whale. As whale lice have no swimming stage they must spread from whale to whale by actual contact, probably during suckling of the young whales.
The only plants found in association with whales at Tory Channel whaling station, were numerous diatoms Licmophora lynbeyi which forms a green scum on the surface of some barnacles. Diatoms have been previously recorded from the skin of whales and attempts have page 19 been made to use them as a means of estimating the area of water from which the whales have migrated.
A close examination of the whale's internal organs shows a large number of internal parasites. There are roundworms, reaching 4 to 5 feet in length in the kidney, other species in the stomach and even in the baleen, while hookworms are often numerous in the intestine. The complete life cycles and intermediate hosts for these parasites are not yet known.
Other organisms not in direct contact with the whales are nevertheless present at the whaling station to prey on those parts of the whale which are rejected as being of no economic value. At the start of the season innumerable hagfish can be seen writhing over pieces of whale organs in the bay and boring their way into the tissue as they devour it. After several whales have been processed, the number of hagfish at the surface declines until none can be seen and it is presumed that they are lying gorged on the sea bottom. When the supply of whale refuse declines after a period of smaller catches, they again appear at the surface among any material still left. By torch light they could be seen at one period in a writhing mass of such density that their super-imposed bodies almost concealed the meat on which they were feeding. There was no evidence to support the allegation that hagfish sometimes bore into living whales.
Large numbers of seabirds are present throughout the season, and do great service in disposing of whale refuse. On entering the bay by launch at night, thousands of medium-sized black and white petrels, the Cape pigeons, can be seen moving about ceaselessly, and occasionally thudding against the windows after being blinded by the light from the launch. Their chattering sounds continue all night in the bay and dawn light reveals them in thousands right up to the slipway. Usually they are observed well away from land in New Zealand waters and nest mainly in the Antarctic area. During the day, they move further out from the factory and the numbers in the bay decline, as many go out to sea. Many of the larger scavenger, the Giant Petrel or Nelly, are also found. On some mornings several hundred could be seen in the bay, and many were so gorged that they were quite incapable of rising from the water until some of the food had been disgorged. A few albatrosses, both Royals and Wanderers, occur at intervals. Both the Red-billed and Black-backed gulls are present in thousands and become more and more in evidence as the day progresses with a reduction in numbers of the Cape pigeons, Nellies and Albatrosses. It is a most ludicrous sight to see a lone gull or Cape pigeon perched on the top of a floating piece of meat many times its own bulk, and vigorously attempting to ward off all other birds so that it can have the piece to itself. Nevertheless, the mass of bird life, as well as the hagfish, are very efficient in disposing of much whale refuse.page 20
This article has been concerned solely with the biological material and information that can be gathered readily at a whaling station. Investigations at a whaling station can also give much indirect information about rate of growth, ageing, feeding and the seasonal movements of whales. Direct observations relating to these problems and whale behaviour and function, can only be made by a study of the living whale at sea, and by marking whales with small missiles fired into the flesh so that the markers can be recovered during flensing if the whale is later captured. Studies of this nature have been made, particularly by the Discovery Expeditions, and are still being continued. It is hoped that such studies will eventually answer many of the unsolved questions associated with the very complete adaptation of these mammals to life in the sea.
- ANREWS, R. C, 1921.
- A remarkable case of external hind limbs in a humpback whale. American Museum Novitates. No. 9.
- LILLIE, D. G., 1915.
- Cetacea. British Antarctic (“Terra Nova”) Expedition, 1910. Nat. Hist. Rpt. Zoology, Vol. 1. No. 3. 85-124.
- OMMANNEM, F. D., 1933.
- Whaling in the Dominion of New Zealand.
- Discovery Reports. Vol. VII. 239-252.