Number Of Whales Research Articles

Grindatøl 1584—1640 og 1709—1978

Statistics for the killing of pilot whales were collected from 1584—1640 and frcm 1709—1978. For the years 1641 —1708 there are practically no statistics. The statistics for 1884—1903 and 1963—1978 have not previously been published, and in the statistics for the other ycars certain corrections have been made. Table 6 shows the statistics for the years 1584—1640.
 For the years 1709—1978 the killings have been examined from various aspects, and divided up according to period, time of year, site of the killing, and the size of the school. Fig. 1 shows the number of schools and the number of individual whales for each year; in fig. 2 the same numbers are averaged, and here a tendency becomes apparent. There are 100—120 yearsbetween really good years. The years 1709—1978 are divided into five periods, A-E, in which each period is the consecutive number of years in which the number of schools and whales has been more or less at the same level. E is exceptionally good, A and C are good, D fairly good, and B exceptionally poor (table 1 and fig. 3). The distribution of schools in months and periods is shown in fig. 4 and table 2. A, C, and E resemble one another, with July and August as the best months (45—50 •/•), in D,August is by far the best month (51 %>); sudden changes occur from one year to the next, e. g. from 1962 to 1963 (fig. 5). The distribution of the killings according to sites is shown in fig. 6 and table 3, 67 %> of schools and 74 (l/o of whales have been killed at 6 sites. The sites have been collected into four groups according to the direction from which the schools have come, west, north, east, and south. Figs. 7 and 8 show thc distribution of killings in relation to these four groups, and the periods (A-E). There are many more schools in the west in D (57 °/o) in proportion to the other periods (17—32 'Vo). The annual average of the incidence of killings in the north, east, and south, is about the same. The distribution of schools according to sizc is shown in fig. 9 and table 4. Again D is outstanding, in 19 •/• of schools there are morc than 300 whales compared with 7—11 °/oin A, C, and E. 
 The factors which may possibly affect the incidence of whale-killings are considered. These factors are partly due to human beings, such as an increase in population, changes in occupation, and technological advancement (improved means of communication and the like), and partly to natural causes. There seems to be a correlation between climatic changes,particularly changes in the temperature of the sea, and the number of killings (fig. 10). Undoubtedly, it is the migration of the schools, rather than their size, which changes. Statistics from 1957—1976 (July—September) indicate a clear correlation between the number of killings and the surface temperature of the sea south-west of Faroe (figs. 11 and 12). From 1966—69 to 1970—74 there was a climatic change (amongst other things in the atmospheric pressure and the temperature of the sea), and in the living organisms in the sea (plant and animal plankton and the like) in the North Atlantic Ocean. At the same time a change in the statistics for whale-killings is seen; the years 1966—69 resemble the good period E, while the years 1970—74 are more like the fairly good period D.

The acoustic environment of humpback whales in Glacier Bay and Fredrick Sound, Alaska

The number of humpback whales frequenting Glacier Bay has been decreasing in recent years while the number of whales in the Fredrick Sound and Stevens Passage area has been increasing. A study was made to determine the acoustic characteristics of both areas and measure the influence of man-made noise sources on ambient levels. ‘Transmission loss (TL) in selected regions of both areas was measured and ambient noise spectra obtained. The TL characteristics for a shallow source and receiver were observed to have a 20 log (range) dependence below 1 kHz in both areas. In Glacier Bay a shallow surface duct was observed which changed the TL to approximately 10 log (range) dependence above 1 kHz. Low ambient noise levels were observed in the absence of boat and ship traffic. Thus the sound from louder vessels dominated the ambient out to a range of up to six miles in some measurements. A significant low-frequency noise contribution, believed to be due to glacier motion, was observed at some locations in Glacier Bay. [Work supported by NOAA, NMFS and National Park Service.]

Seals and whales of the Southern Ocean

There are fewer species of marine mammals in the Antarctic than in the Arctic, probably because of the wide deep ocean with no geographical barriers to promote speciation. The stocks are substantially larger in the Antarctic and the body sizes of individual species are larger, probably owing to a more abundant food supply. Seasonal changes in the environment in the Southern Ocean are marked and food available to baleen whales is very much greater in summer. Ecological interactions of the consumers, principally in relation to krill Euphausia superba , are discussed and attention drawn to some of the ways in which ecological separation is achieved, both within and between species. Estimates of abundances, biomasses and food requirements are given for the seals and large whales. The original numbers of whales in the Antarctic were far greater than in other oceans, but the stocks have been severely reduced by whaling. This may have increased the availability of krill to other consumers by as much as 150 million tonnes annually. Increased growth rates, earlier maturity and higher pregnancy rates have been demonstrated for baleen whale species, and earlier maturity for the crabeater seal. While it has not been possible to demonstrate increases in the populations of any of these species, the stocks of fur seals and penguins have been monitored and show significant population increases. A key question is whether the original balance of this ecosystem can be regained with appropriate management.

Spectral analysis of the long-term oceanographic time series at ocean weather station “P” : ROSS C. K. and G. T. NEEDLER, 1976. J. Fish. Res. Bd Can., 33 (10): 2203–2212

A large scale, systematic, acoustic survey for whales and seals in eastern Antarctic waters was conducted in January-February 2006. During the BROKE-West survey of Southern Ocean waters between 30 and 80° E longitude, an acoustic survey was conducted to complement a traditional visual survey for marine mammal occurrence and distribution. As part of the survey, 145 DIFAR sonobuoys were deployed every 30’ of latitude on north-south transects, and prior to CTD stations on the initial east-west transect. Underwater sound was analyzed for 70 minute samples from each sonobuoy. Blue whales were the most commonly recorded species, identified at 55 of the sonobuoy deployment sites. Other species recorded include: sperm (46 sites), fin (14), humpback (2), and sei (3) whales, and leopard (11) and Ross (17) seals. Large numbers of blue and sperm whales, and all Ross seals were detected on the westernmost two transects, which were the only transects of the survey with relatively extensive sea ice remaining off the continental shelf. Large numbers of blue whales were also detected in the more eastern waters of the survey off the Prydz Bay region, while two detections of pygmy blue whales represent the farthest south these whales have been recorded. Of the relatively few fin whale detections, most occurred in more northerly waters. Fin whale vocalizations from this region were distinctly different than those recorded elsewhere around Antarctica suggesting acoustic recordings may be useful to delineate regional or stock boundaries of this species. Previously undescribed sounds were attributed to Ross seals. Acoustic detections of these and leopard seal sounds indicate these animals venture further from their traditionally described distributions, with vocalizing leopard seals occurring much further north than might be expected. Overall, the results of the sonobuoy survey provide a measure of each species’ relative spatial distribution over the survey area based on acoustic detections, and when combined with the results of the visual survey, will provide a comprehensive view of marine mammal distribution throughout the region during the BROKE-West survey.

Biology of White Whales (Delphinapterus leucas) in Western Hudson Bay

The number of white whales inhabiting western Hudson Bay is about 10,000. In July and early August the herds are concentrated in river estuaries at 57° to 60° N, but a migration in mid-August through September takes them to between 62° and 66°N. Wintering occurs in the western part of the Bay. In the estuary of the Churchill River feeding, mainly on fish, is not heavy and the herds are believed to enter the river estuaries in this region for reproduction as much as feeding. Further north in late summer feeding is heavier and changes towards a diet of decapod Crustacea. It is believed that two dentinal layers are laid down in the teeth each year, each layer consisting of one opaque and one translucent zone of dentine, with the translucent material laid down during periods of reduced feeding. These may occur either at an autumn and a spring migration or during a summer fast at calving time and during winter deprivation. Females attain sexual maturity at 8–13 (mean 10) growth layers and males at 16–18 layers, i.e. at supposed mean ages of 4–7 (5) and 8–9 years. The skin loses all trace of grey color at 18–22 layers. Maximal duration of life is about 50 layers or a supposed age of 25 years in both sexes. The sexes are probably about equal in numbers. Gestation lasts 14 months and lactation about 20 months. Overlap of pregnancy and the previous lactation is infrequent so that calving occurs about once in 3 years. The annual crude birth rate is estimated at 0.12. Estimation of the maximal number of births from counts of corpora luteal scars is complicated by the frequent presence of accessory corpora lutea and luteinized follicles, estimated at about 32% of the total. The mean maximal number of scars retained in the ovaries during a female’s reproductive lifetime is 14.5. The full reproductive lifetime, on the basis of two growth layers per annum, is 20 years. Thus the mean ovulation rate is about 0.7 per annum. Reducing the number of scars by 32% gives 0.5 true (fertile) ovulations per annum, which would indicate a reproductive rate of one pregnancy in 2 years, and a maximal number of 10 pregnancies in a full reproductive lifetime

Analysis of sightings and catches of sperm whales(physeter catodonL.) in the cook strait area of New Zealand in 1963–4

Summary Sighting and catch data on sperm whales accumulated during a whale survey by the New Zealand Marine Department and whaling operations by the Tory Channel whaling company in 1963–4 were examined. The results showed a unimodal rise and fall in numbers of sperm whales in the Cook Strait region throughout the year. From a peak between December and April whale numbers declined steadily until November, when they rose again sharply. It is suggested from these results that the best choice for an eight‐month sperm whaling season would be one extending from November to July. It was concluded that the mean speed of sperm whales in the area was not likely to exceed 1 knot.

Annual Catch of Bowhead Whales by Eskimos at Point Barrow, Alaska, 1928-1960

The number of bowhead whales ( Balaena mysticetus ) taken at Barrow, Alaska, each year from 1928 to 1960 averages 5.8 whales per year. The lengths and dates of capture are given for most of the whales taken in the spring seasons since 1954. Most (72%) of the whales were taken in mid-May. Eighty-eight per cent of the whales were less than 40 feet long, and therefore presumably sub-adult. One was a recently born calf. Another was the largest of record, 61 feet.

Microscopic Structure of the Lungs of the Bottlenose Whale

ONE of the most remarkable structures in the lungs of Cetacea are the sphincters in the respiratory bronchioles. In a number of toothed whales (Odontoceti) the mucosa of these terminal bronchioles shows 8 to 40 consecutive ring-like folds with a circular layer of smooth muscle fibres acting as a sphincter. They may close the passage in the bronchiole completely. They divide the lumen in a number of small consecutive chambers. When the musculature relaxes the passage is re-opened by a system of radially directed elastic fibres, running from the muscular layer to the peripheral layer of cartilage. The sphincters have been described in the common porpoise (Phocaena phocaena (L.)), the bottlenose dolphin (Tursiops truncatus (Mont.)), the common dolphin (Delphinus delphis L.), Prodelphinus caeruleo-albus Meyen, the white whale (Delphinapterus leucas (Pallas)) and in Berardius bairdii Stejneger1 4–9. Several authors showed that these sphincters are not present in baleen whales (Mystacoceti)2,6 7 9. These animals show a very well-developed mass of muscular fibres in the tips of the alveolar septa. Probably these fibres are able to close the alveoles completely.

Sperm Whales Stranded on the Beaches of the Gulf of California

Reports of one or even two whales stranded on the beach are not unusual but the stranding of a number of whales at one time is unusual. Two cases of multiple strandings of sperm whales in the Gulf of California, Mexico, have come to my attention in recent years. Mr. Glenton …

Antarctic Whaling

THE Polar Record for January, a journal which has now widened its scope to include various articles in addition to news of polar expeditions, contains some details of the International Whaling Agreement of 1938. The measures agreed on in 1937 included a minimum size limit for various species, the restriction of the Antarctic whaling season from December 8 to March 7 and the prohibition of pelagic whaling in temperate and tropical waters. Last year the conference went further, though it wasdecided that restrictions on the numbers of whale catchers were impracticable at present. It was, however, agreed to prohibit the killing of humpback whales in waters south of lat. 40° S. for one year. This species is more vulnerable than blue and fin whales, and it is hoped thus tosave the stock from exhaustion. It was also decided to prohibit all pelagic whaling for at least two years in the Pacific waters south of lat. 40° S. between long. 70° W. and 100° W. These waters so far have no pelagic or other whalers and so may well serve as a sanctuary for huntedspecies. In spite of these restrictions, it is admitted that the industryas a whole is probably taking an unduly large number of whales.

False Killer Whales in South Africa

Dr. LEONARD GILL, in the Report of the South African Museum for the year 1935 (1936, p. 10), recounts another of those mass strandings of Pseudorca crassidens which have become so frequent since the reappearance of the species in the Dornoch Firth. The school came ashore at Mamre, about fifty miles north of Cape Town, and the occurrence was peculiar because of the large number of whales stranded, about three hundred, and because they came ashore not on sand but on jagged rocks. But a common feature of the strandings has been, as here, that the whales appear to have been trapped by a falling tide in channels cut off from the open sea by sand-banks. The Mamre stranding took place towards the close of 1935, and seven years before, about the same time of the year, the first record of the species in African waters was made when about a hundred came ashore at Kommetjie, some sixteen miles south of Cape Town.

Whales Stranded in Scotland

SCOTLAND is favoured by the number of whales and whale carcases which are deposited upon its shores, and although this accident of position involves the expenditure of dealing with unsavoury nuisances, it has its scientific value. Accordingly a memorandum has been addressed to Scottish medical officers of health, sanitary officers, and the like, by the British Museum (Natural History), requesting the co-operation of these local officers in recording the stranding of whales, porpoises, and dolphins. Whenever a whale is stranded upon the British coast, a telegram, followed in due course by a detailed report, is sent to the Museum by the receiver of wreck or coastguard, and the Museum telegraphs to the sender to let him know whether the whole or any part of the whale is wanted, either for purposes of identification or for preservation. In this way much valuable information has been gathered in recent years regarding the cetaceans frequenting British waters and their seasonal movements; and the present memorandum aims at extending the scheme of notification. It states that as a rule af ew days' delay does not affect the condition of a stranded whale, that a small whale killed by stranding can lie on a beach for as much as three weeks without giving rise to any serious nuisance and without entailing the slightest risk of infection, and that carcases moored in the water will keep quite well for as long as seven weeks. It is also pointed out that in this matter the British Museum is working in co-operation with the Royal Scottish Museum, Edinburgh, and that an eventual sharing of the specimens between the two museums has been arranged.

A History of the Whale Fisheries: From the Basque Fisheries of the Tenth Century to the Hunting of the Finner Whale at the Present Date

AT the close of the last century whaling appeared likely to terminate at an early date, in view of the great reduction in the numbers of whales which had been brought about by a relentless and long-continued persecution. The rate of destruction had been accelerated by the introduction of modern methods, and if new fields had not been discovered whaling might by now be almost a thing of the past. Dr. Jenkins's book contains a large amount of information which will be of great value to those who wish to satisfy themselves whether the lessons of history confirm the forebodings which have been expressed about the future of whales.

Scientific Intelligence From America*

Scientific Intelligence From America*