Abstract:
UTILISATION OF THE MEAT OF ELEPHANT SEALS M. M. BRYDEN* Summary Body composition of male elephant seals of various ages was determined by anatomical dissection of the main body components. Pups soon after they are weaned, and mature bulls, seem to have the greatest potential for animal production. The relative merits of these two groups are: (1) Weaned pups have the highest body fat content of any age group and the greatest potential value of the skin. (2) Mature bulls reduce labour costs by presenting larger units to work with and contain considerably more muscle per unit live weight. Further, the proportion of muscle on the trunk relative to that on the head and the limbs is greater in the bulls. I. INTRODUCTION The elephant seal (Mirounga leonina) has been slaughtered for its oil for many years, but the carcass has not been used commercially. The carcasses of fur seals (Cullorhinus ursinus) have been used in the past for human consumption (Scheffer 1948) and the meat of whales has been eaten when supplies of meat from domestic animals have been low (Bate-Smith and Sharp 1946). The southern elephant seal is a potential source of large quantities of animal protein. About 1400 kg (approximately 1.4 tons) of meat can be dissected from the carcass of a harem bull. The value of the carcass of this species was recognised by Bonner (personal communication) who stated, however, that economic processing of elephant seal carcasses has not been possible to date. Alterations to sealing methods and quantitative research on the production potential of the carcass could well change this situation. Carrick and Ingham (1962) called for comparative data on production potential of fat, bone and muscle from weaned elephant seal pups and mature bulls in order to determine the relative merits of taking pups or bulls for commercial purposes. The aim of the present paper is to present quantitative data on the meat available from the carcasses of elephant seals in different age classes, and to discuss the relative value of using either weaned pups or bulls for commercial purposes. The data was collected in 1964 to 1966 at Macquarie Island while the author was a member of the Australian National Antarctic Research Expeditions. II. MATERIALS AND METHODS Twelve elephant seals four to nine weeks of age (weaning age is three weeks) and six mature seals 8 to 18 years of age, were used in this study. The mean live *Department of Veterinary Anatomy, University of Sydney, N.S.W. 106 TABLE 1 weight of weaned animals was 120 kg and that of mature animals was 2,340 kg. Only male seal data has been analysed here because there is no significnt difference between the sexes for any of the body components before puberty, and mature females would not be used commercially. The methods of age estimation, slaughter and carcass dissection have been described previously (Bryden 1969). All body composition data were obtained by anatomical dissection. III. RESULTS The percentage of each of the main body components in pups soon after weaning and *in mature bulls is set out in Table 1. The growth impetus (correlation coefficient) of fat, muscle and bone relative to live weight is 0.28, 0.39 and 0.10 respectively. The weight of four muscle groups expressed as a percentage of total muscle weight in recently weaned pups and in mature bulls is set out in Table 2. The growth impetus of the muscles of the head, trunk, forelimb and hind limb relative to total muscle is 0.034, 0.68, 0.051 and 0.030 respectively. Emphasis has been placed on comparison of recently weaned pups and mature bulls in this paper. For ecological reasons these are the only two groups of seals which can be taken commercially. These investigations have shown that recently weaned pups contain more fat per unit of body weight, but less muscle than bulls (Table 1). Added labour is involved in taking weaned pups because more units must be handled. This might be partly offset by the more convenient size of the units. If elephant seal meat were used it is likely that the muscles of the trunk would prove to be more valuable than those of the head and limbs. A large percentage of the trunk muscles is represented by the mass of epaxial and hypaxial TABLE 2 107 spinal musculature, which is easy to remove and contains relatively little fascia and tendon. From this point of view, mature male animals provide a greater proportion of easily attainable meat than young animals due to the greater relative growth ra@e of the muscles of the trunk. However, this would be influenced by the relative quality of the meat in young and mature animals. No data of this type are available at present. A possible advantage. of taking weaned pups is the potential value of the skin. It is difficult to imagine that the skin of a bull elephant seal could be of much commercial value owing to the heavy scarring seen on every large male, but the skin of weaned pups could be of considerable value in the light of the increasing popularity of hair seal skins (Dyke 1964; King 1964). The skin of the weaned elephant seal pup exhibits markings similar to those of the young hooded seal (Cystophora cristata) which is known commercially as a 'Blueback'. The hair of the young elephant seal is coarser than that of the 'Blueback' and less dense, but the markings are desirable and could make the skin an item of some value. Certainly it seems that investigations into the practicability of producing elephant seal skins for commercial purposes are warranted. There is a need for critical assessments of the relative value of the meat of different classes of seals and of th,e quality of meat obtained from different parts of the carcass. V. ACKNOWLEDGMENTS The author thanks the Antarctic Division, Department of Supply, for supporting and financing this project. He is indebted to Mr. W. N. Bonner for discussion and criticism of certain aspects of the work. The assistance of many members of the Australian National Antarctic Research Expeditions, particularly Messrs. J. R. Dart, P. Ormay, D. MacKenzie and C. B. Ellwood, is gratefully acknowledged. VI. REFERENCES B ATE-SMITH, E. C., and S HARP, J. G. (1946). Fd Mf. 21: 371. B RYDEN , M. M. (1969). Aust. J. ZooL 17: 153. CARRICK, R. and I NGHAM , S. E. (1962). C.S.I.R.O. Wildlife Res. 7: 198. D YKE, G. (1964). Fur Trade Rev., Lond., July 1964: 48. K ING , J. E. ( 1964). Fur Trade Rev., Lond., July 1964: 12. S CHEFFER , V. B. ( 1948). Pacif. NW. Q. 39: 13 1. 108