Antarctic Season Research Articles

The External Locations of Harpoon Wounds on Minke Whales Taken in Antarctic Commercial Whaling Operations, 1978/79 Season

AbstractObservations on the external locations of harpoon wounds were made on 127 minke whales Balaenoptera acutorostrata taken during Japanese commercial whaling operations in the 1978/79 Antarctic season. The numbers of wounds per whale did not vary between catcher boats, the average being 1.2. Although the cranio-thoracic region seemed to be the target of choice (bearing 60.5% of all wounds examined), the proportion of wounds in this region varied significantly between catcher boats, ranging from 43.6 to 75.7 per cent. It is suggested that this variation arose because to hit the cranio-thoracic region, the first section of the whale to surface, requires considerable skill on the part of the gunner.

Surface layer ozone above the Weddell Sea during the Antarctic spring

Ozone concentrations in the atmospheric surface layer above the Weddell Sea during the Antarctic spring season of 1989 varied significantly. Lower levels of ozone were associated with colder Antarctic air masses and higher values with warmer mid-latitude air. The lowest ozone concentration (1 to 2 ppbv) was measured in the centre of a low pressure system. A definite diurnal variation of tropospheric ozone observed during clear days with low total ozone amount (177 matm cm) may be interpreted as a consequence of the occurrence of photochemical reactions under conditions of increased ultraviolet solar radiation.

Global Trends in Total Ozone

Satellite ozone data from the Total Ozone Mapping Spectrometer from 1979 through 1986 show that recent decreases of total ozone have not been confined to the Antarctic spring season (the Antarctic ozone hole), but are global in extent. The losses are about twice the estimated uncertainty in the satellite data. The decreases are largest in middle and high latitudes and occur in all seasons of the year. The decreases for this 8-year period are comparable in magnitude to the increases observed during the 1960s. Southern Hemisphere values from 1986 are generally greater than those from 1985.

Biological Parameters of the Antarctic Minke Whale at the Virginal Population Level

New data from Japanese catches in Antarctic seasons 1971–72 and 1972–73 are used to calculate biological parameters. Determinations are: fetal sex ratio (52.0% females); sex ratio in catch (54.1% females); [Formula: see text], males (27.9 ft), females (29.5 ft); age at asymptotic body length, males (18–20 yr), females (20–22 yr); male sexual maturity at testis weight (0.4 kg); length at beginning of sexual maturity, males (21 ft), females (24 ft) and at 50% sexually mature, males (23.6 ft), females (26.2 ft); age at sexual maturity, females (6 yr); apparent pregnancy rate (89.5%); annual ovulation rate (0.866); litter size (1.007); natural mortality coefficient of sexually mature sample (0.127) and of sexually immature sample (0.213); age at recruitment (6 yr); and rate of recruitment in virgin population (0.119).

Study of Antarctic Ice Sheet Motion by Means of Doppler Effect Laser Equipment

Doppler-effect laser equipment was successfully employed in Antarctica in 1969-70 to measure the rate of ice-sheet motion. The method is based on measuring differential beat frequency generated by the interaction of the direct pulse and its echo. A He-Ne laser with the wavelength of 6 328 Â was used in the 15th Soviet Antarctic Expedition. The paper gives detailed results of the measurements along with a description of the equipment used and of the observational procedures. A new modified version of the equipment was made ready for 1971-72 Antarctic season, and was used in the 18th Soviet Antarctic Expedition in the vicinity of Mirny station. New results are also discussed. Analysis of all available data makes it possible to believe that the movement of the ice sheet is irregular with occasional stops. The progressive motion of the ice sheet is accompanied by strain oscillations.

Study of Antarctic Ice Sheet Motion by Means of Doppler Effect Laser Equipment

Doppler-effect laser equipment was successfully employed in Antarctica in 1969-70 to measure the rate of ice-sheet motion. The method is based on measuring differential beat frequency generated by the interaction of the direct pulse and its echo. A He-Ne laser with the wavelength of 6 328 Â was used in the 15th Soviet Antarctic Expedition. The paper gives detailed results of the measurements along with a description of the equipment used and of the observational procedures. A new modified version of the equipment was made ready for 1971-72 Antarctic season, and was used in the 18th Soviet Antarctic Expedition in the vicinity of Mirny station. New results are also discussed. Analysis of all available data makes it possible to believe that the movement of the ice sheet is irregular with occasional stops. The progressive motion of the ice sheet is accompanied by strain oscillations.

Far Southern Animals and Plants

IN recent years the southern limits of known natural occurrence of animals have been pushed farther south, and during the 1964–65 Antarctic season several new southernmost records were established. Records of the most southern plant collections made this season are also included here.

Age Determination and Reproduction of Female Fin Whales Balaenoptera Physalus (Linnaeus, 1758), with Special regard to Baleen Plates and Ovaries

1. From Antarctic female Fin Whales, Balaenoptera physalus, a collection, consisting of baleen plates and the parts of these plates embedded in the gum, ovaries, and a number of earplugs was examined, in order to determine the age of these animals and to get a better insight in some characteristics of their reproduction. Data concerning pregnancy and lactation were also recorded. The material was sampled from animals worked up on board the f.f. “Willem Barendsz” during the Antarctic seasons 1953/1954 to 1959/1960 inclusive. The possibilities and values of age determination for this species were considered, based on the results of the analyses of the above material. 2. In most seasons the length distribution of the female Fin Whales, from which the material for the age determination was sampled (“examined animals”), did not differ significantly from that of the total catch of females of the “Willem Barendsz” in the same seasons. Neither was there any significant difference in length distribution between the total number of females from which the material was sampled and that of the females in the catch of the “Willem Barendsz” in all seasons. However, the length distribution of the catch of the “Willem Barendsz” differed significantly from the total Antarctic pelagic catch. 3. Baleen records were made according to the method described by RUUD (1940). In contrast with his age determinations with the aid of the part of the baleen plate protruding from the gum also the part of the plate hidden in the gum was used. A method of reading this part was developed. The advantage of this method is that the total length of baleen plate examined is much longer, and that the part hidden in the gum is not yet worn. In addition, the use of the part hidden in the gum has the undeniable advantage that the end of the cortical layer at the base of the “root” of the baleen plate represents the only exact date: the date at which the animal was killed. 4. Apart from the large waves of the cortical l

HMS Protector: Antarctic season, 1960–61

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The Operation of a survey motor boat in Antarctic waters, 1956–58

During the Antarctic summer seasons of 1956–57 and 1957–58, a British Royal Naval Hydrographic Survey Unit operated off the coast of west Graham Land. Working sometimes from stations of the Falkland Islands Dependencies Survey, and sometimes from camp sites, an area of coastline from Port Lockroy southwards to Ferin Head was systematically examined, triangulated and charted.The mobility of this small unit depended on one all-important factor, the constant availability of a specially converted 29 ft. motor boat, which acted as both transport and home.

International Whaling Commission

At a whaling conference in London, in June 1959, representatives of the United Kingdom, Japan, the Netherlands, and Norway again failed to reach agreement on a national quota arrangement for whaling in the Antarctic, a problem which they had been discussing intermittently since November 1958. At the end of the futile talks, Norway resigned from the International Whaling Convention. The Netherlands subsequently followed suit, leaving only die United Kingdom, Japan, and the Soviet Union as members. In consequence, no over-all international quota was fixed for die 1959–1960 season, scheduled to open on December 28. However, the International Whaling Commission reportedly agreed at its eleventh annual meeting diet the maximum permissible catch of whales for the Antarctic season 1959–1960 should not be changed, the figure remaining at 15,000 blue whale units. The blue whale stocks in the North Atlantic were considered to be too low for exploitation at present, so this species was scheduled for complete protection.

南氷洋に於ける捕獲鯨の組成

The present account deals with the results of direct observations on the humpback whales brought into the floating factory “Kyokuyo-maru” during the Antarctic season 1938/39. Dur-ing the period extending from 18th November 1938 to 8th February 1939, a total of 248 whales was examined and more than 70% of them were caught in the area between 61°-63°S. and 100°-105°E. (1) Of 248 humpbacks examined 174 were females and 74 were males ; thus the sex-ratio of the whales showed great segregation of females in the above-mentioned area. (2) The colour pattern of the humpbacks was divided by LILLIE'S method according to the gradation occurred in the amount of black and white as shown in Fig. 2. The colour type of the whales was rather alike to that of New Zealand group than that of South Africa and South Georgia groups. The differences in colour were not accompanied by any other distinguishable characters. (3) Examination of the genitalia showed That female humpbacks become sexually mature at a length of about 12•1m. This length is somewhat shorter than that (12•5m) suggested by MATTHEWS (1937). The smallest mature female recorded was 10•9m. long while the largest immature one was measured 12•4m. (4) The average number of corpora lutea of 89 females (the average length of which was measured 12•78m.) was 4•78. It was seen from this that female humpbacks were consisted of average same age during the 1924-1931 season at South Georgia and South Africa and during the 1938/39 season in the mentioned area. (5) Of 16 adult females with only one corpus luteum 10 were pregnant, I was lactating and 1 was recently ovulated or pregnant. Thus at least 11 (69%) whales would be estimated as they were pregnant in the first breeding season and nearly the same results were obtained also in the whales with two or three corpora lutea. It might be tentatively concluded same as blue whales that number of unfertilized ovula-tions or formations of corpora atretica before pregnancy, if any, must be very few. Neither multiple ovulations nor multiple pregnancies were observed throughout the season. (6) The apparent constitution of the, stock i.e. the ratios of the different classes of whales examined might be summarized as follows. (See page 52). High proportion of pregnant whales among mature whales were obvious against low pro-portion of resting and recently ovulated or pregnant whales when compared with blue and fin whales. (7) Assuming the females caught belong to an independent stock, the stock of whales in the area were tentatively calculated (WHEELER'S method on fin whales was adopted) not wi th standing insufficient data and heterogeneous composition of the catch. Analysis of the age groups of mature females determined by the corpora lutea during the season showed a rate of reduction of 32% on an average and besides it was proved by calcu-lation that as there produced only about 64% of immature females necessary to keep the stock at its present level, considerable damage is being done in the area concerned.

Discovery II: An Appreciation of the Work Done During her Third Commission

The Royal Research ship, Discovery II, arrived at St Katherine's Dock, London, on July 4, thus completing her third commission, like the others of twenty months' duration so as to cover two Antarctic summer seasons. The scientific work has this time been in the charge of Dr N. A. Mackintosh, with Mr H. F. P. Herdman as chief hydrologist, and Lieutenant A. L. Nelson, R.N.R., in executive command.

Antarctic Whaling Season, 1932–33

Antarctic Whaling Season, 1932–33

Antarctic Whaling Season, 1932–33

Antarctic Whaling Season, 1932–33