7

PREFACE

The first International Symposium on the Biology papers were read by title and are included either in of the Seal was held at the University of Guelph, On­ full or abstract form in this volume. The 139 particip­ tario, Canada from 13 to 17 August 1972. The sym­ ants represented 16 countries, permitting scientific posium developed from discussions originating in Dub­ interchange of a truly international nature. lin in 1969 at the meeting of the Marine Mammals In his opening address, V. B. Scheffer suggested that Committee of the International Council for the Ex­ a dream was becoming a reality with a meeting of ploration of the Sea (ICES). The culmination of such a large group of pinniped biologists. This he felt three years’ organization resulted in the first interna­ was very relevant at a time when the relationship of tional meeting, and this volume. The president of ICES marine mammals and man was being closely examined Professor W. Cieglewicz, offered admirable support as on biological, political and ethical grounds. well as honouring the participants by attending the The scientific session commenced with a seven paper symposium. section on evolution chaired by E. D. Mitchell which The programme committee was composed of experts showed the origins and subsequent development of representing the major international sponsors. W. N. this amphibious group of higher vertebrates. Many of Bonner, Head, Seals Research Division, Institute for the arguments for particular evolutionary trends are Marine Environmental Research (IMER), represented speculative in nature and different interpretations can ICES; A. W. Mansfield, Director, Arctic Biological be attached to the same fossil material. Readers of this Station, Fisheries Research Board of Canada (FRB) volume should be aware of such differences when read­ represented the International Commission for North­ ing the papers in this section. The twelve papers of west Atlantic Fisheries (ICNAF); and K. S. Norris, S. H. Ridgway’s section on functional anatomy illus­ Director, Marine Mammal Council Executive Com­ trated the fundamental structure of the seal, as well mittee, represented the International Biological Pro­ as its associated control mechanisms. R. J. Schusterman gram (IBP). The Food and Agriculture Organization followed this theme by introducing ten papers on be­ of the United Nations (FAO) also offered its support haviour. He established a major focus on social or­ to the programme and ICNAF has contributed to the ganization and communication and their association financing of this volume. with the functional anatomy of the pinnipeds. D. E. Sponsors of national origin were the Fisheries Re­ Sergeant chaired the population dynamics section of search Board of Canada (FRB), the National Re­ seven papers, covering the modelling of populations search Council of Canada (NRCC), the Canadian and method of analysis of seal populations around the National Sportsmen’s Show (CNSS), the World Wild­ world. In the fifth section, J. R. Geraci, by means of life Fund (Canada) (WWF), and the University of papers and a panel discussion dealt with the care and Guelph. management of captive pinnipeds. W. N. Bonner co­ In his preliminary remarks Professor Ronald intro­ ordinated a presentation in the broad area of ecology, duced the representatives of these groups; namely J. R. and was able to bring together studies on environmen­ Weir, Chairman, Fisheries Research Board of Canada; tal factors and their associated behavioural and gene­ S. Bata, International Director and J. S. McCormack, tic control systems. The physiology section was chaired Director, World Wildlife Fund (Canada); and R. T. by H. T. Andersen, his introductory remarks forming D. Birchall, President, Canadian National Sportsmen’s the initial paper of the section. The other six papers Show and a Director of WWF (Canada). of his section emphasized the underwater responses of W. C. Winegard, President of the University of seals. The final and general section, chaired by J. E. Guelph, welcomed participants to the symposium and King, offered a broad coverage of several of the more commented particularly on how pleased he was to interesting areas in various disciplines. welcome representatives from so many countries. Later, A. W. Mansfield acted as rapporteur for the entire at a banquet sponsored by the Department of the En­ programme, and his report stressed the need for con­ vironment, Canada, he offered an invitation to the tinued cooperation by all biologists so that they might group to return in 1975 for a Second International understand seals and their importance to environmen­ Seal Symposium. tal studies. Altogether 62 papers were presented. A further 14 This volume includes with one exception, those pa- 8 K. Ronald pers either presented, read by title, or abstracted, but mammals of the world’ by D. W. Rice and V. B. the continuing discussion on the biology of the seals Scheffer (U.S. Fish and Wildlife Service, Washing­ led to one further paper that is included here. Some ton, 1968) has been used as the standard reference on of the discussion was formal and, where recordable, is nomenclature. included here, but by far the greater part of discussion The work of the chairmen of each of the seven sec­ was informal and hence must remain as extremely tions of this volume is especially recognized. As well, valuable, but merely mental recollections of the par­ the convenor wishes to thank the programme com­ ticipants in the symposium. mittee for their ability to support a somewhat unortho­ The symposium achieved its purpose of bringing dox procedural system, and particularly the sponsors together scientists interested in the Pinnipedia and it ICES, ICNAF, IBP, CNSS, FRB, NRCC, WWF (Ca­ offered leads into the international examination of nada), FAO, and the University of Guelph for their marine mammals. valuable financial assistance. The editors with little apology recognized that they The convenor is most grateful to Mr. H. Tambs- have not reached a completely uniform format in this Lyche, General Secretary of ICES, for his advice and volume since they have allowed use of both English encouragement from the embryonic stages of the sym­ and metric systems of measurement and both English posium to the publication of the proceedings; he also and North American word usage for the sake of har­ recognizes the considerable amount of expert help pro­ mony. The main editorial structure has been the con­ vided by A. W. Mansfield in co-editing this volume. sistency of usage throughout a particular paper. Finally, the effort put into both the symposium and Attempts have also been made to attain a fairly this volume by Mrs. Ginny Bandesen has been beyond uniform taxonomy for the species, but where there has measure, but I hope that she will accept the results of been any doubt caution has not overridden clarity. As the symposium recorded here as tangible proof of her in other mammalian groups, the systematics of the most valuable contribution. To the members of the Pinnipedia are still open to much interpretation. The Dean of the College of Biological Science’s office, the references are cited according to an Annotated Biblio- university support staff and our host Dr. W. C. Wine- praphy on the Pinnipedia*. The ‘List of the marine gard, I express on behalf of the participants and my­ self, our sincerest thanks. * Ronald, K., L. M. Hanly and P. J. Healey, College of Bio­ K. Ronald, logical Science, University of Guelph, Ontario, Canada. Convenor

The following have kindly acted as Discussion Care and Management Section Leaders of the different Sections and also assisted in J. R. Geraci the editing of the contributions: Department of Zoology, University of Guelph, Guelph, Ontario, Canada. Evolution Section Ecology Section E. D. Mitchell Arctic Biological Station, Fisheries Research Board W. N. Bonner of Canada, Ste. Anne de Bellevue, Quebec, Canada. Seals Research Division IMER, c/o Fisheries Labora­ tories, Lowestoft, Suffolk, England.

Functional Anatomy Section Physiology Section S. H. Ridgway H. T. Andersen School of Anatomy, University of Cambridge, Nutrition Institute, University of Oslo, Blindern, Cambridge, England. Oslo, Norway.

Behaviour Section General Session R. J. Schusterman J . E. King Department of Psychology, California State University Department of Zoology, University of New South Hayward, California 94542, U.S.A. Wales, Kensington, N.S.W., Australia.

Population Dynamics Section Summary D. E. Sergeant A. W. Mansfield (Rapporteur) Arctic Biological Station, Fisheries Research Board of Arctic Biological Station, Fisheries Research Board Canada, Ste. Anne de Bellevue, Quebec, Canada. of Canada, Ste. Anne de Bellevue, Quebec, Canada. 416

Rapp. P.-v. Réun. Cons. int. Explor. Mer, 169: 416-420. 1975.

ECOLOGY SECTION DISCUSSION

W. N. B on n er

Ling: It has been suggested on the basis of its light Mansfield: We haven’t actually put this down in natal coat that the grey seal may have originated as numbers at all but it is something that we would like an ice-breeding species. However, Curry-Lindahl has to measure in the future. O ur studies of grey seals recently suggested that the ice-breeding habit of Bal­ have lacked many of the behavioural aspects so far. tic grey seals is of very recent origin, within the last Perhaps we can improve them in the future. 10 000 years. I’m wondering how these ideas fit in with your suggestion that the colonisation of islands Schurman: At Nantucket there is only one pup bom off the British coast is of recent origin. a year on the average and the mother is usually in the water, instead of on the sand with the pup. Bonner: I don’t think that there is an easy explanation for this. The origin of the grey seal is still shrouded in Bonner: This is probably generally true in those colo­ mystery and I don’t want to enter this particular mist nies where the density is low; but even where the den­ myself. I feel also that the disparity in size between sity is high, cows will go and lie in any bit of water the male and the female grey seal is another argument available. A lot of wallows start from puddles used by against the evidence of comparatively recent colonisa­ cows in this way. tion of terra firma, so I simply haven’t made up my mind on this one. Mansfield: Your pictures of grey seals actually de­ stroying the vegetation on the Farne Islands are rather McLaren: Could you clarify your statement that the interesting because the opposite seems to be occurring disparity in size of males and females suggests that at Sable Island. The grey seals there seem to be ini­ there wasn’t a recent invasion from the ice, or was it tiating the growth of dune grasses at the eastern end vice versa? I wasn’t quite sure. of the Island and it appears to me that dunes are ac­ Bonner: I was thinking merely that polygyny on the tually forming where the seals have been lying in large numbers; but this is the sort of thing we have never ice was less likely to occur if they were spread out had time to quantify. It’s just an impression over the there and I can’t see any reason why the males should last ten years of field work at the island. be so much bigger than the females unless they are polygynous. Bonner: That is a most interesting observation because Schurman: In your paper you mentioned that, asso­ it shows how complex are the relationships between ciated with these denser colonies, there was a stronger animals and their immediate habitat. A little may be tie between the mother and the pup and this was not a very good thing and a lot may not. We can see the observed in some smaller colonies. I wondered what same effect with bird colonies where a moderate the people studying grey seals in other areas have amount of nitrogenous manuring from the excreta of found? the birds is a great help to the vegetation; but if there is too much the vegetation changes to algae. Bonner: What I observed, in fact, is that there is more of a spatial relationship between mother and pup in Mansfield: One of the difficulties we have in estimat­ the denser colonies because of the site tenacity shown ing numbers of harp seals by aerial photographic me­ by the females. I don’t know of other quantified data thods is to know precisely what is the behaviour of the for other colonies. Has anyone got any suggestions? female seals. I would like to ask Dr. Popov if, in his What about the conditions on Sable Island? studies on the White Sea, he has observed any diurnal Ecology Section Discussion 417

variation in the behaviour of the females which have Odell: In answer to the second question, we don’t pupped. know which way evolution is going. Territoriality could be building up, just as well as breaking down and my Popov: In making the aerial photographs a specially- data can be interpreted as supporting the suggestion equipped aeroplane flies at a height of about 500 m made by Peterson and Bartholomew. On how pupping over the ice to obtain a full picture of the chosen area. times were measured, the first phase was from the As a lot of the females will be in the water it is neces­ time when a female was first seen to be in labour to sary to calculate a special coefficient to determine the the time when I saw the pup. This results in a mini­ proportion of females not appearing in the photo­ mum value only. As Le Boeuf pointed out to me a little graph. This is a very difficult problem. At present we earlier, you can’t really see when the pup is starting use the following method for counting females in the down the birth canal, but only when the pup is emerg­ water. ing. In that sense the time is an artifical measure de­ The chosen ice floe is labelled with its own mark pending on which way the birth goes. In cephalic which is visible from the air. Provided the day is clear birth, which may well take as long as breech birth, the aeroplane crosses this floe in the morning, in the the nose is out when you start timing it. In breech middle of the day, and in the evening. At the same birth you see the hind flippers but the female is still time the scientists count the number of pups on the working on the head and shoulders. I suppose that floe (they do not need to count the females as these delivery of the placenta is straightforward and does will be visible on the aerial photograph). If, for ex­ not affect the timing. ample, there are 100 females on the floe and the num­ ber of pups is 200 it follows that there are 100 fe­ Morejohn: Apparently I worded my first question in­ males in the water. We suppose that the average number correctly. Would you repeat the method of arriving at of females in the water on the day of the aerial survey the comparison between delayed implantation in Cal­ serves as a special coefficient for females which were lorhinus and Zalophus? absent from the ice. The number of pups on the floe is usually constant. For example, if during the day we Odell: The aborted Zalophus pups started appearing photograph about 50 000 females we may add the on the beach on San Nicolas Island in January. I took coefficient for females in the water on the day of the a series of measurements on all the aborted pups that aerial survey. I could find right up to the middle of May. Growth A paper has been published on this problem and in weight of the foetus was plotted against time and a those interested will find it in the publications of regression analysis was carried out. I had to assume VNIRO, Moscow. that the aborted pups were normal in all other re­ spects, and that abortion resulted from some abnor­ Sergeant: This methodology is very clear, but do the mality of the female. The data from Callorhinus were results show that there is a regular diurnal cycle, for collected from foetuses taken at sea and these were example in dear weather? subject to a regression analysis. I calibrated the system with the Callorhinus data and obtained intersections Popov: This method was first used in the 1970’s and with the time axis in mid-November, and in mid- we shall try it out again on the ice in 1973. We can October for Zalophus. see the distribution of the males on the ice from the air very well. We can see a group of males on the ice, Bigg: Dr. Naito told us when birth took place in the perhaps 500 males in one group, and we tend to count Kurile seal and in Phoca largha in his area, and also them on the photograph from the air. The use of the lactation times. Could he give us an idea of when aeroplanes for counting females in the White Sea is mating and implantation take place? restricted to not more than four days. Naito: I ’m not sure about this. In Phoca largha, m at­ Morejohn: I have two questions for Dr. Odell, the ing may occur during the weaning season because we first one involving your comparison between pupping can capture an adult female with her pup, together in Callorhinus and Zalophus. How did you do this? with an adult male, on one ice floe. In the Kurile seal The second one is just a thought to throw out, and re­ mating may also take place during the suckling season. fers to your concept of decaying territorial behaviour. We are not sure about implantation. Why not view it the other way? Why should not polygyny in Zalophus be an incipient form of evolving Ling: I would have expected the blubber, which is an behaviour? aquatic adaptation toward insulation, to have been

27 418 W. N. Bonner thicker in the precocious P. kurilensis than the ice- colony, but spent most of their time under water, I breeding and later-swimming P. largha. However, assumed that they were territorial. this is not so. Why? Ray: It really doesn’t follow that they were territorial. Naito: The reason is still not clear, but I suppose that Kaufman: No. Admittedly on the basis of our observa­ the ice-breeding largha seals are deserted by their mo­ tions or calculations we cannot say anything with cer­ thers and utilize the blubber as an energy source as tainty. This is obviously the place where we need fur­ shown by the decrease in thickness between weaning ther study to document the size and characteristics of and leaving the ice at 1-5 - 2-5 months of age. the territory.

Ling: Possibly the minimum blubber thickness for ade­ Mitchell: I noticed in Dr. Müller-Schwarze’s first slide quate insulation is about 3-0 cm. that there was a very marked pigmentation pattern on the leopard seal; a dark dorsal pigmentation with a Stirling: Since Dr. Reichle followed some of the same lighter ventral colour, and the flipper was light in co­ animals from year to year, particularly the non-terri- lour. There appeared to be a distinct “water line”. Is torial males which were marked and apparently mo­ this related to the cruising behaviour of the leopard ved so much, I would like to know how much of that seal as he searches for penguins, and are there any movement might have been caused by the stress of other possibly adaptive features of the pigmentation handling? pattern?

Reichle: That would be a little hard to estimate. We Müller-Schwarze: This hasn’t been a special point of did not classify the males as territorial or non-territo­ our observations, but leopard seals are like Weddell rial at the time of tagging. Territorial males were seals and other seals in having this division of dark those that we identified on TV generally. The tracking and light when they haul out. Also the darkness or data would not substantiate the social position. lightness of the fur or the spots vary from individual to individual. Bonner: I get the impression that Weddell seals are Ray: Did you ever see a leopard seal actively making rather resistant to handling but one can’t afford to or enlarging a hole in the ice? You showed one hole make that sort of assumption. It’s a difficult thing to there, but it looked like a Weddell seal hole. test. Müller-Schwarze: These holes are pushed through ice Reichle: We would get a reaction from seals we had up to about 20 cm thick by leopard seals in pursuit of tagged. Certain animals would react to the arrival of penguins. Every time leopard seals see or hear pen­ the tracked vehicle by moving towards the hole, and guins on top of the ice they follow their path and we were generally correct in assuming that these ones break through the ice near them. They very rarely were tagged. use the same hole again, and do not enlarge it. The holes have nothing to do with Weddell seals at all. Ray: Could you tell me how you determined whether a seal was territorial or not? Did you determine that Mansfield: Can you comment on the diet of the leo­ it was territorial because it was not moving much, or pard seal outside the breeding season of the penguins? because it actually acted like a territorial male and Müller-Schwarze: There are scattered reports in the chased others away and so forth? literature from earlier antarctic expeditions on the diet of leopard seals. You will find almost everything eaten: Reichle: The territorial behaviour was documented on fish, shrimps, cephalopods and so forth. We have also the television system; that is, we saw the male in the seen them eating other seals, but it is not clear whether Hutton cliffs area on our daily censuses and he stayed they picked up dead or dying seals, or whether they below the ice a large proportion of the time as indi­ actively killed them. cated in the paper given by Dr. Kaufman. Morejohn: Penguins are marked in the same way as Kaufman: In reply to Dr. Ray’s first question, I would leopard seals, light underneath, dark on top, suggesting say that some of the territorial males were identified that the pattern has an adaptive signficance. Has the as territorial by observation on television. Others be­ leopard seal ever been seen to prey on the penguin haved similarly, and because they were there in the under water, while the penguins were diving for fish? Ecology Section Discussion 419

Müller-Schwarze: All the attacks in pursuit of pen­ In a small isolated human population of up to about guins occurred under water, and we never saw the ac­ 1000 people you would find abnormalities which might tual event. When leopard seals are very desperate, repeat themselves in some sort of sequence. The fea­ especially early in the season, they do reach up on the ture of 4 post-canine teeth will not necessarily have ice floes. W hen there is just a single ice floe and noth­ been selected against at Sable Island. The Sable Is­ ing around but water, the penguin that is being chased land seals are feeding a lot on very small fish and they jumps on the ice and you can see the leopard seal wouldn’t necessarily be required to get a good grab at come up from one side. The penguin runs to the other the fish like other seals found along the mainland coast side of the floe. If the floe is small, say 5 m across, the of Nova Scotia. leopard seal comes to the other side, reaches up, caus­ ing the penguin to run back again. There may be as Bonner: I think in fact we are dealing here with a dis­ many as 10 attacks in a row on a small ice floe, but cussion about technical terms. Inbreeding to a geneti­ this is atypical. The vast majority of attacks and kills cist means sibling mating and this is most unlikely to are under water. go on in a wild animal population of more than 20 or I must add here another point I forgot to mention 30, I suppose; but you were really talking about a in my talk. In the Antarctic Peninsula we visited 24 closed genetical system, weren’t you? rookeries ranging all the way from 36 breeding pairs to 65 000 breeding pairs of all three species of Pygo- Boulva: Yes. scelid penguins, and we did not find any signs of leo­ pard seal activity at all in rookeries below about 10 000 McLaren: The two concepts cross somewhat when you pairs. All the leopard seals hunting penguins, or consider the possibility of the founder population bloodstained penguins at the beaches, were seen at which may well have been involved here. Seals were certainly much scarcer in the last century and during rookeries larger than 10 000 pairs. But these are just spot checks. We need more information on this. the earlier part of this century according to the re­ cords.

Bonner: This is a very interesting paper because it Wartzok: Dr. Lavigne why did you speculate that the shows an exceedingly rare behaviour pattern for leo­ point of maximum sensitivity in the scotopic curve pard seals. There are very many leopard seals in the being around 500 nm was an adaptation for life in Antarctic only a minute fraction of which are preying green waters, instead of saying that as in most mamma­ on penguins. There just aren’t that many penguin lian rod receptors the pigment is one of the retinal rookeries in terms of miles of accessible coast where based pigments, all of which have a maximum senti- leopard seals can feed. Quite clearly leopard seals tivity of about 520 nm. feed predominantly on other food organisms, but be­ cause you get this concentration of biologists at pen­ Lavigne: The scotopic curve is determined by a lot of guin rookeries, the penguin-feeding habit is what gets things but primarily by the pigment rhodopsin in the reported on. While in South Georgia I was interested retina. There are many forms of rhodopsin. In fishes to note that leopard seals were just about evenly and whales analysis has shown that the visual pigment spread along the coast. They were fairly territorial in correlates highly with the colour of the light in the their feeding activities and only those which were environment the animal is living in. If you take a very lucky enough ot have a penguin rookery in their deep swimming fish or deep diving whale, the rho­ territories could feed on penguins; and they would dopsin will peak somewhere around 460 to 490 nm. also be taking penguins from tiny rookeries of about If you take an animal that lives in green coastal wa­ 30-40 pairs. ters, a fish, for example, their visual pigment will peak around 500 nm. The visual pigment in the California Shaughnessy: I just thought I would comment on Mr. sea lion peaks around 500 to 502 nm. In other words Boulva’s use of the word inbreeding. He said that your basic assumption that all mammalian rhodopsins harbour seals on Sable Island are an inbreeding group. peak around 520 is not really true. Human rhodopsin, I think it is rather unlikely that the population of 1200 depending on whose work you read, peaks around 497 seals would be inbreeding. I would rather tend to des­ or 493 nm, and most rhodopsins in terrestrial mam­ cribe them as a discrete group of animals, unless he mals peak around 500, not 520 nm. But in the marine has evidence of inbreeding. environment, visual pigments tend to correlate with the colour of the light in that environment. If a seal Boulva: I do not have any direct evidence of inbreed­ was diving to 2—300 m in open ocean it would be ing. I was just suggesting this as a possible explanation unusual for it to have a visual pigment peaking near of those variations which were not reported elsewhere. 500 nm.

27* 420 W. N. Bonner

Wartzok: I’m still not convinced that this is true. I’m seals, we have seen something about the trophic rela­ not familiar with the rhodopsin from the whales you tionships of seals, that of the leopard seal and the mentioned. Could you correlate the depths of their Adélie penguin. Perhaps more than anything else we dives with the maximum absorption? would like to see more quantified studies of feeding in seals so that we would know a little more about their Lavigne: McFarland in 1971 published a paper on marine habits and how they fit in with the marine visual pigments in cetaceans. He studied 10 cetaceans ecosystem. The paper on the leopard seal has shown and found that the generalisation that has been well us much of the relationship between seals and this lo­ documented for both marine and fresh water fish held cally enormously abundant prey resource. We have in general for the 10 whale species studied. heard something of the temporal relationship of har­ bour seals on Sable Island and this must relate to cli­ Bonner: At the beginning of this session I suggested matic factors and to the way in which natural selec­ that I would attempt to say what my concept of ecolo­ tion is fitting the Sable Island seals to their environ­ gy was. I feel I have come no closer to defining it in ment. Visual acuity in harp seals was not originally the course of this afternoon but I think we must ac­ part of this programme, but I’m prepared to welcome cept that ecology is essentially the relation of an ani­ it because animals are not going to be able to react to mal, or a system, to its environment and of course it is their environment unless they’ve got sense organs, and important to realise that the environment is very wide we are not going to understand how these sense organs spread indeed. Where you have social breeding ani­ operate unless we carry out more of the sort of work mals, then a factor of major importance in this envi­ which has been presented to us by Lavigne and Ro­ ronment is the other members of the same species. nald. In the course of papers this afternoon we have seen I do not think that I can attempt to sum up these how grey seals affect both the habitat where they live papers and I feel that we are not going to lack very and how they are affected by their neighbours. We much because of that. I am quite confident that we have heard how harp seals are affected by climatic shall go on talking about these things, about indivi­ factors and by the currents and tides of the sea in dual papers and how these relate to those in other which they live. We have seen how sea lions react to sessions, but in the moments that remain I am going each other at that most important part of their life to thank on your behalf all our speakers and those cycle, the breeding season, and we have heard how who participated in the discussion. I would like to two very similar species of Phoca are distributed in thank the speakers for keeping so well to the rather the environment. rigid time scale that I imposed and I think we all The range of Weddell seals through their environ­ should give special thanks to those speakers for whom ment, and the contact with it, has been described and, English is not their mother tongue and who do not perhaps what we most desire in ecological studies of have the opportunity of hearing it spoken every day.