BULLETIN DE L'INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE BIOLOGIE, 67-SUPPL.: 105-112, 1997 BIOLOG1E, 67-SUPPL.: 105-112, 1997 BULLETIN V AN HET KONINKLIJK BELGISCH INSTITUUT VOOR NATUURWETENSCHAPPEN

Natural disease problems of the sperm whale

by Richard H. LAMB ER TSEN

Abstract

This paper reviews observations made over the years on natural disease in sperm whales. Most of the information available is derived from past whaling activities. This information, with biological data defining normal body condition and blubber lipid content, provides a starting point for the evaluation of natural phenomena as causes of sperm whale strandings. For example, depression of blubber lipid content was found by others in many of the sperm whales which stranded in 1994/1995 in the North Sea, and is consistent with SMEENK's hypothesis (this vo­lume) of a general process of starvation in a shallow sea essentially devoid of those pelagic cephalopods which constitute the sperm wha­le's principal prey. Cross-disciplinary data derived from whales stranded on the North Sea coast in 1994/1995 are also considered with the concern that pollution may have contributed to, or caused these strandings. However, the pathological details, plus the fact that the one Belgian whale with hemorrhagic skin ulcers had severe weight loss, the lowest blubber lipid content measured, and carried the lowest concen­tration of lipid-soluble toxicants, all suggest that any specific cause of death linked to the pathogenesis of the skin ulcers was not related to pollution. Further research into this question is strongly encouraged.

Keywords: sperm whale, disease, stranding, lipids, starvation, pollu­tion, toxicants.

L'article passe en revue les observations qui ont ete faites au cours des temps sur les maladies naturelles des cachalots. L'essentiel de !'infor­mation disponible provient de la peche baleiniere d'autrefois. Cette information, notamment les donnees biologiques definissant la consti­tution normale du corps et le contenu en lipides du lard, offre un point de depart pour !'evaluation de phenomenes naturels susceptibles de causer les echouages de cachalots. Par exemple, des chercheurs cons­taterent un abaissement de la teneur en lipide du lard chez beaucoup des cachalots qui s'echouerent en mer du Nord en 1994/l995, en accord avec l'hypothese de SMEENK (ce volume) qu'un processus general de privation alimentaire s'engage pour ces animaux dans une mer peu profonde d'ou les cephalopodes pelagiques - qui consituent la proie principale des cachalots- sont pratiquement absents. On examine aussi les donnees multidisciplinaires sur les baleines echouees sur les cotes de la mer du Nord en 1994/1995, dans la crainte que la pollution puisse avoir cause, ou contribue a causer ces echouages. Toutefois, celui des cachalots echoues en Belgique qui montrait des ulceres hemorrhagiques de la peau souffrait aussi d'un grave amaigrissement, avait dans le lard la teneur en lipide la plus basse et avait la plus faible concentration en toxiques liposolubles. Ces faits, en plus des details pathologiques observes, suggerent que toute cause specifique de la mort liee a la pathogenese des ulceres de la peau etait etrangere a la pollution. Des recherches supplementaire sur cette question sont vive­ment encouragees.

Mots-cles: cachalot, maladie, echouage, lipides, privation alimentaire, pollution, toxiques.

Introduction

Since any whale will die if it fails to breathe air, the triad of loss of appetite, decreased body fat and reduced bouyancy that often accompany prolonged organic dis­ease will likely predispose natural stranding events. In the aftermath of these events, veterinary pathobiologists are often asked to establish the proximate cause of a strand­ing. As such, some background on the subject of whale pathobiology is essential. What are the naturally occur­ring diseases of the sperm whale? What is it like to conduct a necropsy on this species?

At the outset, I should say the conduct of a necropsy examination on a sperm whale (I have done about 30 with varying degrees of thoroughness) is without question the least pleasant scientific task in which I have ever engaged. Like the balaenopterid whales, sperm whales are large. But, they are also tough. Their blubber is espe­cially fibrous, stiff and difficult to cut. This quality of toughness, coupled with the subject's enormous size, makes the necropsy of a sperm whale a dangerous affair. Tremendous force often must be applied during the pro­cess. Hooks, cables and power winches all are needed to open the carcass for internal examination. The epithelium of the esophagus and the first compartment of the sto­mach is comparatively thick and does not cut easily even with a very sharp blade. There may be rocks and gravel inside to dull repeatedly your cutting tools (NEMOTO and NAzu, 1963). Bucketsfull of nematodes are commonly present, sometimes still writhing about. There seems to be no end of small intestine (another peculiarity of the sperm whale) (SLUPER, 1962). Last, the squid, fish and seal diet of the sperm whale gives rise to gut contents that are more offensive in smell than those of baleen whales.

I know that we pathobiologists are supposed to be immune to these sorts of "stimuli" -heroically wading in self-imposed (if imaginary) sensory shut-down- but I must begin by noting how absolutely remarkable it is that T . JAUNIAUX and his colleagues (JAUNIAUX et al., this volume) have actually performed pathological examina­tions on several sperm whale bulls that stranded on a beach in winter! In my experience, the necropsy of a

106 Richard H. LAMBERTSEN

Table 1 - Ectoparasites known to infest the sperm whale

Taxon

Diatoms Cocconeis ceticola v. arctica C. ceticola v. constricta Stauroneis aleutica Nitzschia closterium Navicula sp. Sinedra sp. Licompofora sp. Plimosigma sp.

Location on Host

Epidermis

Reference

BERZIN, 1971 BERZIN, 1971 NEMOTO, 1956; KL Y ASHTORIN, 1962 MATTHEWS, 1938 MATTHEWS, 1938; TOMILIN, 1957 KLYASHTORIN, 1962 KLYASHTORIN, 1962 KLYASHTORIN, 1962

Lampreys

Shark suckers

Epidermis, especially tail stock

Epidermis, dermis

BERZIN, 1971

BERZIN, 1971

Whale lice

Cyamus boopis Cyamus cataodonti Cyamus bahamondei Cyamus ovalis Neocyamus physeteris

Epidermis, especially genital, teat, and anal slits

BERZIN, 1971 fRANSEN and SMEENK, 1991 LEUNG, 1965

Stalked Barnacles (Cirripedia)

Conchoderma virgatum Conchoderma cuvier Conchoderma auritum

Anchor Worm (Copepoda)

Penella balaenoptera

Teeth

Epidermis, dermis

recently caught sperm whale is an awful and challenging task even on a flensing deck equipped with some 14 thoughtfully placed steam winches.

Pathobiology of the Sperm Whale

On external examination of any reasonably large series of male sperm whales in high latitudes, one is impressed by the variable severity and extent of scarring of the head. Because the wounds that bulls inflict upon each other tend to heal without complete repigmentation, the scars stand out from an otherwise dark gray epidermis and accumulate with age. The skin may be overgrown with diatoms, or may show signs of recent parasitism by lam­preys or cooky cutter sharks (BERZIN, 1971), but there rarely is evidence of infestation with the parasitic cope­pod Penella balaenoptera (Table l ). Whale lice ( Cyamus and Neocyamus spp. ) may be found, especially in the recesses of the genital and anal regions, or in the folds at the corner of the mouth. Sometimes, diatoms invade the epidermis in dense patches that occur as multiple small gray macular lesions, each a few millimeters in diameter (LAMBERTSEN and KOHN, 1987, fig. 1 C). In addition, fistulae extending inward from the skin surface well into the dermis commonly are sparsely scattered about the body surface (ibid, fig. 1B). These fistulae are 2-3 cm in diameter and generally have surrounding epidermal

LEUNG, 1965 MARGOLIS and PIKE, 1955

FREUND, 1932; CLARKE, 1966 FREUND, 1932 BERZIN, 1971; CLARKE, 1966

MATTHEWS, 1938; BERZIN, 1971

cell proliferation. Inside the mouth, the ivory teeth some­times carry a few goose-necked barnacles ( Conchoderma sp. ), or may themselves be carious. The dental ligament and gums may be affected by minor periodontal disease. The upper teeth of the sperm whale usually are not erupted, of course, although they typically do occur as ivory rudiments in the soft tissue. The lower jaw may be grossly deformed, in some cases giving the appearance of a developmental defect (SLIJPER, 1962). Inflammation of the pharyngeal tonsils has been noted (COCKRILL, 1960).

Of the 31 sperm whale bulls I examined in Iceland in the 1980's, three were grossly afflicted externally with the venereal disease known as genital papillomatosis (LAMBERTSEN et al., 1987; LAI\1BERTSEN and KoHN, 1987; LAMBERTSEN, 1990). Electron microscopic exam­ination of the papillomatous lesions revealed widely scat­tered aggregates of small round or hexagonal particles within the nuclei of epidermal cells. These presumptive viral particles were of a size (28-40 nm), location and shape consistent with the papillomaviruses. In other spe­cies, papillomaviruses are known to be oncogenic (indu­cing formation of the tumor); in females they have been causally linked to the emergence, by malignant transfor­mation, of cervical cancer. Whether malignant transfor­mation of cervical papillomas occurs in the female sperm whale is unknown. BERZIN (1971) did report the finding of a tumor 40 cm in diameter on the cervix of a female

sperm whale caught in the North Pacific, but alas, gives no histopathological details.

On internal examination, one typically finds very large numbers of anisakid nematodes in both the posterior esophagus and the first and second compartments of the stomach (Table 1). Generally, these parasites are free in the lumen, that is, not attached to the stomach wall. In unusual cases, large numbers of worms invade the wall of the second compartment of the stomach and form dense verminous plaques. In the region covered by these plaques there are hemorrhagic ulcers of the mucosa (LAMBERTSEN and KOHN, 1987, fig. lE) that can be both large and multiple. These can perforate the mu­cosa, extending into the muscular tunic of the stomach wall.

Complete perforation of the stomach wall in these areas, with subsequent death of the whale due to perito­nitis, presumably is possible in very severe cases. It is not clear, however, whether the anisakids are the cause of these ulcers or merely secondary invaders of a mucosa that is compromised first by physical injury or systemic stress. Many, often sharp, bones from fish typically are found in the first compartment, which may also contain small rocks and gravel. If these find their way into the second compartment, some injury to the mucosa would be expected. The extent of intraspecific combat, as in­dicated by the scarring of the head, would suggest also that the bull sperm whale, at least, leads a rather stressful life.

In the small intestine and bile ducts, one finds a variety of cestodes (Table 2), depending to a large extent upon geographic region, but these tapeworms are probably of little pathological consequence. Acanthocephalons, how­ever, generally are present in the small intestine. Because these worms have chitinous hooks on their heads, which they use for attachment to the mucosa, they may cause considerable enteric damage and inflammation. Amber­gris, when present, typically is located at the colorectal junction. Ambergris takes the form of a stercolith (a "fecal rock") that usually is lodged in the rectal lumen. When such stercoliths are large, they undoubtedly cause the whale considerable discomfort and constipation, for they plug the anal canal. In individuals so affected, epithelial erosion and ulceration may occur in the sur­rounding rectal mucosa.

The spirurid Placentonema gigantissima, the largest nematode known, infects the reproductive tract and pla­centa of the female sperm whale. The adult female worm may reach 8.4 m in length and 2.5 cm in diameter. It is proposed that the maturing parasite, to reach such gigan­tic size, uses the special nutrition and immunological barrier provided by the placenta, plus a transcuticular mode of feeding (SKRY ABIN, 1960). The parasite is not known to damage the developing whale fetus, though heavy infections may compete to some extent with the fetus, compromising its immune system.

The cardiovascular system, including the aorta and coronary arteries, commonly shows signs of atherosclero­sis. In each of four hearts they examined, TRUEX et al.

Natural disease problems of the sperm whale 107

(1961) found multiple atheromatous intimal plaques in the marginal, interventricular and ventricular arteries. These plaques were composed of proliferated tissues, predominantly fibrous elements, of a very similar nature to the atheromatous lesions in human arterial disease. One whale also showed clear macroscopic signs of myo­cardial infarction, extending from the interventricular septum into the left ventricular wall. Thus, some sperm whales (despite a "healthy" fish and cephalopod diet) evidently have heart attacks and would suffer angina pectoris.

TRUEX et al. (1961) also reported the finding of "adult" nematode worms 125 mm long and 2.5 mm in diameter in both the right ventricle and the pulmonary arteries. These workers, however, did not give any histo­logical confirmation of the maturity status of the nema­todes they found, or detailed descriptions of the worms, as they were primarily interested in the coronary vascu­lature. It is important that future studies attempt to more thoroughly characterize the nature and prevalence of the sperm whale heartworm infection, noted also by MARGO­us (1954).

In examining the cardiovascular system, the anatomi­cally astute pathobiologist will observe that the right ventricular veins anastomose with large tributaries of the coronary sinus. It has been surmised (TRUEX et al., 1961) that this arrangement provides a safety system to shunt high pressure arterial blood back to the heart during periods of dive-related compression. The distinctly flat­tened, twin-apexed heart, with greater equality in left and right ventricular wall thickness, in addition suggests adaptation to dive-induced increases in the resistance to blood flow through the lungs; in land mammals this cardiac configuration would suggest congenital valvular disease or chronic pulmonary hypertension (OCHRYMO­WYCH and LAMBERTSEN, 1984).

The kidneys generally are free of grossly discernable parasitic infection (contrary to CocKRILL's (1960) claim that sperm whales are infected with Crassicauda spp. ) but may contain small calculi (BERZIN, 1971) or cysts (ibid; LAMBERTSEN and KoHN, 1987).

Neoplastic disease other than that associated with pa­pilloma virus-like particles apparently is rare in sperm whales. Reports with adequate histopathological descrip­tion include a fibroma of the skin of the lower jaw, a fibroma of the skin near the blowhole, a hemangioma of the liver (SOLK, 1953), and fibromyomata in the uterus (Uvs and BEST, 1966). The large tumour found on the cervix of a female sperm whale noted by BERZIN ( 1971) has already been mentioned.

Microbial Disease

Our entire knowledge of presumptive microbial disease in the sperm whale is limited to histological and ultrastructural observations on virus-associated genital papillomatosis, serological observations on neutralizing activity against marine caliciviruses, the finding of Sar-

108 Richard H. LAMBERTSEN

Table 2 - Endoparasites known to infest the sperm whale

Taxon

Trematoda (Flukes)

Order Fasciolata Family Campulidae Zalophotrema curilensis

Cestoda (Tapeworms)

Order Cyczophyzzidae Family Tetrabothriidae Tetrabothrius ajfinis

Tetrabothrius curilensis Priapocephalus grandis Trigonocotyle sp.

Order Tetraphyllidea Family Phyllobothriidae Phyllobothrium delphini

Tetraphyllidae sp. (larvae)

Order Trypanorhyncha Trypanorhyncha sp. (larvae)

Order Pseudophyllidea Family Diphyllobothriidae Diplogonoporus sp. Multiductus physeteris Tetragonoporus calyptocephalus Hexagonoporus physeteris Ploygonoporus giganticus

Nematoda (Roundworms)

Order Ascaridida Family Anisakidae Anisakis physeteris

Anisakis skrjabini

Anisakis catadontis Anisakis dussumieri

Anisakis ivanizkii Anisakis simplex** Anisakis pacificus

Order Spirurida Family Crassicaudidae Placentonema gigantissima Nematode sp. (probable spirurid)

Location on Host

bile ducts

intestine

small intestine intestine small intestine

skin, subcutaneous connective tissue

subcutaneous connective tissue

stomach wall

bile ducts bile ducts bile ducts small intestine intestine

stomach

stomach, small intestine

stomach stomach, large intestine

stomach stomach, intestine stomach

placenta, uterus heart, right ventricle, coronary veins

Acanthocephala (Thorny-headed worms)

Order Palaeacanthocephala Family Polymorphydae Bolbosoma turbinella** Bolbosoma brevicolle ** Bolbosoma capitatum ** Bolbosoma physeteris Corynosoma strumosum **

Corynosoma curilensis Corynosoma mirabilis

** Occurring in North Atlantic.

intestine intestine intestine small intestine intestine

small intestine intestine

Reported Occurrence

Sea of Okhotsk (Kuriles)

Atlantic Ocean (Northern and Southern Hemispheres), Pacific Ocean (New Zealand), Antarctic Sea of Okhotsk, Pacific Ocean South Africa, South Georgia, Azores Sea of Okhotsk

Atlantic Ocean, Mediterranean Sea, Pacific Ocean, Australia, Antarctic Atlantic Ocean (South Georgia), Pacific Ocean (Kuriles)

Pacific Ocean (Kuriles)

Pacific Ocean (Kuriles) Antarctic Pacific Ocean (Kuriles) Pacific Ocean (Kuriles) Antarctic

Atlantic Ocean (Saldanha Bay, South Georgia), Indian Ocean (Durban), Pacific Ocean (Japan), Antartic (Ross Sea) Pacific Ocean (Commander and Kurile islands), Antarctic Atlantic Ocean (Saldanha Bay) Pacific Ocean (Japan, Commander Islands)

Pacific Ocean (Commander Islands) North Sea, Pacific Ocean, New Zealand Pacific Ocean (Kuriles, Commander Islands)

Pacific Ocean, Antarctic North Pacific

Atlantic and Pacific Oceans (North and South) Atlantic Ocean (North and South) Atlantic Ocean, Mediterranean Sea Pacific Ocean (Kuriles), Antarctic Atlantic Ocean; Baltic, White, Barents, Kara, & Caspian Seas; Pacific Ocean Pacific Ocean (Kuriles) Antarctic

After S.L. DELYAMURE and A.S. SKRYABIN (in BERZIN, 1971); DELYAMURE, 1955; REES, 1953 ; and TRUEX et al., 1961.

Natural disease problems of the sperm whale 109

Table 3 - Presumptive microbial pathogens of the sperm whale

Location found Reference

Viruses

*Papilloma virus Epidermis, genital papillomas LAMBERTSEN et al., 1987 LA!\1BERTSEN and KoHN, 1987 SMITH and LA THAM, 1978 **Calicivirus

Other?

Bacteria

***Vibrio jluvialis ***Pseudomonas sp. Other?

Protozoa

Sarcosporidia sp.

NA

Blowhole Blowhole

Muscle

BucK et al., 1991 BUCK et al., 1991

0WEN and KAKULAS, 1968

* intranuclear papillomavirus-like particles identified by electron microscopy of epidermal papillomas. Disease identified by anatomic pathology in 3 of 31 bulls examined in Iceland, 1981-1982.

** serum neutralizing actiYity found, but this hematologic evidence of infection has not been linked with any anatomic pathological evidence of disease.

*** bacterium isolated from routine swabs, but this microbiological evidence of infection has not been linked with any anatomic pathological eYidence of disease.

cosporidia sp. in muscle tissue and the incidental finding of Vibrio fluvial is and Pseudomonas sp. upon culture of material from blowhole swabs (Table 3). In the case of the caliciviruses - which have a potentially serious im­pact on population health, and which pose a potential foreign disease threat to land mammals - no virus-asso­ciated lesions have ever been reported, and the possible role of the virus as an autonomous cause of disease in the sperm whale is entirely speculative.

Ingestion of Foreign Objects

It is noteworthy that in male sperm whales killed by commercial whalemen between Iceland and Greenland, 12 of 32 (37.5%) examined pathologically had ingested some sort of plastic or metallic human trash. Lethal disease caused by complete obstruction of the gut with plastic marine debris was inferred in one of these cases (LAMBERTSEN, 1990). Table 4, in addition, gives a rather sobering list of the types of man-made articles actually

Table 4 - Types of man-made debris noted in the gut of 3 1 sperm whales taken in Icelandic commercial whal­ing operations, 1981 and 1982 (LAMBERTS EN, unpu­blished).

Fishing net Plastic and metallic buckets Polypropylene line Rubber gloves Shampoo and various other plastic bottles Tampon dispensers

found (LAMBERTSEN, unpublished data). The risk of in­gestion of plastic materials may be especially significant in the sperm whale due to its propensity for feeding on the bottom, probably by a suction mechanism (see also CLARKE; EVANS; LOCKYER; all in this volume). By com­parison, evidence of ingested plastic marine debris was rarely found in postmortem examinations of fin whales (Balaenoptera physalus) and sei whales (Balaenoptera borealis) (LAMBERTSEN, 1990), which feed in the water column.

Discussion

Owing to its derivation from whaling activities, the in­formation on natural disease just reviewed provides in­sight mainly into problems found normally in living populations. From this review we see that science to date has identified only two naturally occurring diseases in the sperm whale of sufficient potential severity to cause death: 1) myocardial infarction associated with coronary atherosclerosis; 2) gastric ulceration associated with invasive anisakiasis. Virulent disease caused by the ingestion of plastic marine debris also has been de­tected.

Natural disease, nonetheless, should be viewed a priori as the probable proximate cause of both single and mass strandings of cetaceans. To reach this conclusion, one must only accept that the sperm whale, like all sea mammals, is constrained by a respiratory system that evolved secondarily, not primarily, for aquatic existence. With a respiratory system that depends on air, a diseased sperm whale may decide to swim ashore simply as the least undesirable - or most misunderstood - choice be-

110 Richard H. LAMBERTSEN

tween two devastating life options: grounding or drown­ing.

As already stated, the triad of loss of appetite, de­creased body fat and reduced bouyancy that often accom­pany prolonged organic disease will likely predispose natural stranding events. Grounding of a large whale in tidal regions, moreover, raises the likelihood of severe impairment of breathing, since the rib cage in Cetacea is modified to allow collapse of the lungs during dives (KOOYMAN and ANDERSEN, 1960). Pathophysiologically, one would predict compromised cardiac and cerebral oxygenation, with rapid deterioration of physiological status and psychomotor function, as the tide receeds. Grounding related trauma and associated pain during incipient brain hypoxia likely also would bring fear, mental disorientation and the stressed vocalizations of agony - the latter potentially attracting other members of a social group into dangerous shallows. General dis­orientation, group panic, and mass stranding may ulti­mately occur.

With this concatenation of pathogenic events, the stranding of groups of sperm whales is predictable not only when a single member of a group grounds upon being overwhelmed by some specific chronic severe organic disease. It is also expected when a healthy mem­ber of a group grounds by accident in a tidal zone and consequently suffers hypoxic, fear- and stress-induced breakdown of central nervous and other body systems. The situation where malnutrition or limited food suppy is the primary cause of disease and disability is only a special case within the expected range of patholo­gical causes. Here, the inadequate supply of food can be viewed to be the etiology, or cause, of the impair­ment of bodily function leading to the stranding. As we shall see, however, food inaccessibility may itself be related to geographic and oceanologic considerations, and seasonal migratory urges, particularly for sperm whales entering the North Sea in autumn (SMEENK, this volume).

One can conclude that pathobiological study is of primary importance to understanding the proximate cause of virtually all cetacean strandings, but that specific severe chronic organic disease may well be lacking in many stranded whales. This is not to down­play valid concerns about adverse effects on wildlife health played by various toxic pollutants. The recent past has seen unprecedented mass mortalities of small marine mammals. In several instances these have been linked to morbilliviral epizootics that might in fact have been exacerbated by toxic immunosuppres­sion caused by a polluted diet (DE SwART et al., 1994; Ross et al., 1995; DE SwART and OsTERHAUS, 1995).

Less clearly understood is the significant parallel in­crease in both live and dead strandings of sperm whales in the North Sea and adjacent waters. The sperm whale feeds lower on the food chain than most seals and dolphins, such that bioaccumulation of toxicants is expected to be less (LAws et al., WELLS et al. both in

this volume). Also, the sperm whale typically feeds in deep offshore water, not the more polluted coastal zone (CLARKE; EVANS; LOCKYER; all in this volume). Even so, in late 1988 and early 1989, at least 36 sperm whales were reported dead in the North Sea region, nine afloat, the remaining stranded on the Norwegian coast (CHRISTEN­SEN, 1990). At least five other sperm whales stranded during the same period of time on the coasts of Sweden, Denmark, Belgium and the Faroe Islands; the following year, 12 dead sperm whales beached on the Eire and UK west coasts and, on the Norwegian coast, an additional twenty (BERROW et al., 1991 ).

Laboratory and field data obtained from another 21 sperm whales that stranded in 199411995 on or near the North Sea coast (CLARKE; JAUNIAUX et al.; JOIRIS et al.; WELLS et al.; all in this volume; LAW et al., 1996), interpreted with a view of geography and natural history (DE SMET; EVANS; LOCKYER; SIMMONDS; SMEENK; all in this volume), provide real insight into possible roles played by pollution in the stranding of sperm whales in the North Sea. Depression of blubber lipid content in many of the animals examined (WELLS et al., Table 1, this volume), for example, suggests a general process of starvation in a shallow sea essentially devoid of those pelagic cephalopods which constitute the dominant prey of the sperm whale. Furthermore, among the more thor­oughly studied Belgian strandings, hemorrhagic ulcera­tions of the skin, occurring as large oval cutaneous lesions that have not been reported in any previous pathological study of sperm whales, were found only in the one animal that had the extreme lowest lipid content measured in its blubber. This was sperm whale #3, the 14.4 m male that stranded at Koksijde on 18-11-94 (JAUNIAUX et al., this volume; JAUNIAUX, pers. comm.; sperm whale B3 of WELLS et al., Table 1). No other hemorrhagic lesions were found in any of the stranded whales, other than simple erosions of probable traumatic origin incidental to the grounding event. The only excep­tion, among the larger 1994/95 group, was one of the Dutch strandings, sperm whale "A", which also had hemorrhagic cutaneous ulcers (JAUNIAUX et al., ibid). Other novel cutaneous lesions, classifiable as acute to chronic by the microscopic character of their inflamma­tory cell infiltates, were not hemorrhagic; these could well represent various stages of a general ulcerative process caused by a single, potentially lethal, systemic disease.

The laboratory diagnosis of starvation based on the lipid content of blubber samples at this writing must be viewed as tentative (see discussion about variance in blubber lipid content measurements in Wells et al, this volume). Nonetheless, a very high probability of starva­tion in sperm whale #3 was confirmed by the weight determinations carried out in Belgium. The data from T. JAUNIAUX and company's Herculean effort to weigh the sperm whales stranded, interpreted against LOCKYER's (1991) own monumental past work establishing a weight­to-length relationship for this species, demonstrate a se­vere, 32% loss of body mass in sperm whale #3 compared

with normal (JAUNIAUX et al., Table 3, this volume). Unfortunately, no comparably objective confirmation of severe weight loss is available for sperm whale "A". At Scheveningen, sperm whale "A" presented with grossly similar, actively hemorrhagic lesions which, on the basis of microscopic characteristics (polymorphonuclear cell infiltration) appeared significantly more acute than those found at Koksijde on sperm whale #3 (which were char­acterized by lymphocytic infiltration; JAUNIAUX et al., this volume). The major difference noted in the inflam­matory cell infiltration implies that, at the time of death the hemorrhagic cutaneous lesions in sperm whale ''A'' were at an earlier phase in their natural progression than the similar hemorrhagic lesions seen in sperm whale #3 (classified microscopically as subacute, see JAUNJAUX et al., this volume).

In this context, the individual toxicological data for the Belgium strandings presented at the 1995 symposium in Koksijde, Belgium were most revealing (case data for total PCBs and DDE to be published elsewhere; but see JOIRJS et al., Table 1, this volume; or JOIRIS et al., 1995). Those data indicate that sperm whale #3, even with its severe weight loss and its extremely low blubber lipid, also had the lowest concentrations of the lipid-soluble toxicants in its tissues (expressed either per gram of tissue or per gram of tissue lipid in liver or muscle). Moreover, the relatively extremely low levels of toxicants in the tissues of sperm whale #3 occurred even though starva­tion should have rapidly elevated the tissue concentration of total PCBs and DDE. As critically reviewed by WELLS et al. (this volume), starvation "ages" the chemical pattern in this and more complex ways, because the breakdown of body fat mobilizes lipid-soluble toxicants and leads to their redistribution within a reduced total body volume.

In synthesis, then, the accumulating evidence would seem significant. It indicates that the one whale said to have the lowest concentration oflipid-soluble toxicants in its tissues probably suffered a prolonged period of starva­tion and also developed hemorrhagic cutaneous ulcers. It furthermore suggests that any specific disease that might be responsible for both the pathogenesis of the unusual lesions observed and the deaths of the whales generally was not caused by pollution. The reason is because the least contaminated of all the whales examined, sperm whale #3, happened to show the strongest pathological signs of impaired disease resistance. That is, at the time of death, only sperm whale #3 had multiple subacute cuta­neous ulcers that were still bleeding, in addition to chronic lesions (JAUNIAUX et al., ibid).

Additional research to evaluate this prima facie inter­pretation of the data would appear more than warranted. The Belgian Prime Minister's Impulse Programme in Marine Science and the Management Unit of the North Sea Mathematical Models have clearly taken leadership roles in this challenging area of scientific endeavor, internationally. These agencies should be strongly en­couraged to continue their important cross-disciplinary work.

Natural disease problems of the sperm whale 111

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Richard H. LAMBERTSEN Ecosystems Technology Transfer, Inc.

P.O. Box 6788, Titusville Florida, USA 32782

and Veterinary Specialists Group Species Survival Commission

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