A. Lagacé

Levels of organochlorine chemicals in tissues of beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Québec, Canada

High levels of organochlorine chemicals (OC) were found in the blubber of 26 stranded carcasses of beluga whales from an isolated population in the St. Lawrence Estuary (Québec, Canada). These compounds accumulated with age in both sexes, being consistently more concentrated in male tissue; high and variable concentrations were found in four juveniles. Lower levels in females are best explained through massive transfer to the newborn during lactation, resulting in juvenile OC concentrations equal to or higher than in adult males. Concentrations in the liver and kidney expressed on a lipid basis suggest dynamic OC exchange between tissues. The adipose tissue concentrations reported here were higher or equal to those found In some pinnipeds, in laboratory animals, and in domestic animals with severe reproductive failure. These findings suggest that OC contamination is a major factor in the non-recovery of the St. Lawrence beluga population over the last decades.

Toxic Compounds and Health and Reproductive Effects in St. Lawrence Beluga Whales

An epidemiologic study was carried out over a period of 9 years on an isolated population of beluga whales (Delphinapterus leucas) residing in the St. Lawrence estuary (Quebec, Canada). More than 100 individual deaths were aged, and/or autopsied and analyzed for toxic compounds, and the population was surveyed for size and structure. Arctic belugas and other species of whales and seals from the St. Lawrence were used for comparison. Population dynamics: Population size appeared to be stable and modeling showed this stable pattern to result from low calf production and/or low survival to adulthood. Toxicology: St. Lawrence belugas had higher or much higher levels of mercury, lead, PCBs, DDT, Mirex, benzo[a]pyrene metabolites, equivalent levels of dioxins, furans, and PAH metabolites, and much lower levels of cadmium than Arctic belugas. In other St. Lawrence cetaceans, levels of PCBs and DDT were inversely related to body size, as resulting from differences in metabolic rate, diet, and trophic position, compounded by length of residence in the St. Lawrence basin. St. Lawrence belugas had much higher levels than predicted from body size alone; levels increased with age in both sexes, although unloading by females through the placenta and/or lactation was evidenced by overall lower levels in females and very high burdens in some calves. No PCDDs and only low levels of some PCDFs were detected in St. Lawrence belugas, while proportions of toxic non-ortho (coplanar) PCBs were low relative to proportions seen in other species. At least ten different PCB methylsulphone metabolites were detected in St. Lawrence belugas. Levels of B[a]P adducts to DNA in St. Lawrence beluga brain and liver approached those associated with carcinogenis in small laboratory animals. Pathology: St. Lawrence belugas were not emaciated, and major findings were: a high prevalence of tumors (40% of animals) including eight malignant neoplasms; a high incidence of lesions to the digestive system (53%), to the mammary glands (45% of adult females), and to other glandular structures (11%); some evidence of immuno-suppression; frequent tooth loss and periodontitis. Two animals had severe ankylosing spondylosis and another was a true bilateral hermaphrodite. No such lesions were observed in 36 necropsies of Arctic belugas and of seals and cetaceans from the St. Lawrence.

Pathology and toxicology of beluga whales from the St. Lawrence Estuary, Quebec, Canada. Past, present and future

Abstract An indigenous population of 450–500 beluga whales (Delphinapterus leucas) inhabiting the St. Lawrence Estuary has been exposed chronically for more than 50 years to a complex mixture of industrial pollutants including organochlorinated compounds (OC), polycyclic aromatic hydrocarbons (PAH) and heavy metals. From 1983 to 1990, we have necropsied 45 well preserved carcasses out of a total of 120 beluga whales reported dead over this period. Of these 45 animals, nine were affected by 10 malignant neoplasms. Fifteen animals (33%) were affected by pneumonia. Milk production was compromised in eight of 17 mature females (41%), by inflammatory changes (seven animals) and cancer (one animal) which affected the mammary glands. Opportunistic bacteria were found in pure culture, and/or in significant amounts in at least two organs in 20 belugas (44%). The concentrations of both total PCBs and highly chlorinated PCB congeners were much higher in St. Lawrence animals than in Arctic beluga whales. OC-induced immunosuppression has been repeatedly demonstrated in a wide variety of animal species. Therefore, it is probable that the immune functions of St. Lawrence beluga whales are impaired. Benzo[α]pyrene adducts were detected in 10 of the 11 St. Lawrence beluga whales of which tissues (six livers, 10/11 brains) were analyzed by a method based on HPLC. No such adducts were found in four Arctic animals. Since benzo[α]pyrene is one of the most potent chemical carcinogens known to man, these compounds might be responsible for some of the cancers observed in that population. Overall, our findings contrast vividly with those of others who found that cancers are exceedingly rare in free-ranging odontocete populations and that the major causes for mortalities in these populations are bacteria, parasites, and trauma.

Tumors in St. Lawrence Beluga Whales (Delphinapterus leucas)

A population of 450–500 belugas (Delphinapterus leucas) resides in the polluted estuary of the St. Lawrence River. Stranded carcasses of this endangered population were recovered and necropsied. High concentrations of organochlorines, heavy metals, and benzo-a-pyrene exposure were demonstrated in tissues of these whales. Between 1988 and 1990, 21 tumors were found in 12 out of 24 carcasses. Among these tumors, six were malignant and 15 were benign. The animals were between 1.5 and >29 years of age, and the ages of animals with and without tumors did not differ when two juvenile animals (1.5 and 3.5 years of age) were excluded. Seven other neoplasms had been reported previously in six out of 21 well-preserved carcasses examined in the same laboratory between 1982 and 1987. Overall, 28 of the 75 confirmed tumors reported so far in cetaceans (37%) were from this small population of beluga whales in the St. Lawrence Estuary. Such a high prevalence of tumors would suggest an influence of contaminants through a direct carcinogenic effect and/or a decreased resistance to the development of tumors in this population.

Non-neoplastic lesions in beluga whales (Delphinapterus leucas) and other marine mammals from the St Lawrence Estuary

In a 3-year (1988-1990) pathological study, 24 carcasses of beluga whales from the St Lawrence Estuary, Québec, Canada, showed numerous severe lesions, many of which had never been reported in cetaceans. The most common lesions were found in the digestive tract (21 animals) and consisted mainly of periodontitis and of erosions and ulcers in the oesophagus and the first two gastric compartments. Pneumonia, usually of parasitic origin, was also a common finding (12 animals). The adrenal glands often contained nodules (five animals) or cysts (seven animals), and mastitis was observed in five females. Overall, the incidence of degenerative, infectious, hyperplastic or necrotic lesions, in addition to numerous neoplasms described in another paper, was considerably higher than that found in marine mammals elsewhere or in other species of marine mammal from the same waters.

True Hermaphroditism in a St. Lawrence Beluga Whale (Delphinapterus leucas)

A hermaphrodite beluga whale (Delphinapterus leucas) was found in the St. Lawrence Estuary, Quebec, Canada. This animal had two testicles, two separate ovaries, and the complete ducts of each sex; cervix, vagina and vulva were absent. Mature spermatozoa were found in the lumen of seminiferous tubules in the testicles, and numerous involuted corpora lutea were recognized in the ovaries. This represents the first case of true hermaphroditism in a cetacean, and is the fourth hermaphrodite mammal with two testicles and two separate ovaries.

Gastric papillomas in eight St. Lawrence beluga whales (Delphinapterus leucas).

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Rupture of a dissecting aneurysm of the pulmonary trunk in a beluga whale (Delphinapterus leucas).

and total nasal length (abnormal = 28.3 mm; normal = 34.1 mm) were considerably shorter for the abnormal fawn and indicated decreased rostral length. P, (first premolar) to occipital condyle also was shorter for the abnormal skull (85.6 mm vs. 90.4 mm). Rostral breadth at P, , a measure of the swollen frontal bone, was wider for the abnormal skull (41.0 mm vs. 28.2 mm). The curved rostrum and dentaries may have developed from a nutritional deficiency. Twisted rostrums are characteristic of calcium deficiency, phosphorus toxicity, or atrophic rhinitis (Church and Pond, 1974, Basic Animal Nutrition and Feeding, 0 and B Books, Corvallis, Oregon, 300 pp.). However, we examined the nasal turbinates and found no evidence of bone resorption. Therefore, we suspect that these anomalies were congenital. We thank P. R. Nichols for laboratory assistance, J. D. Plucker for photographic assistance, and G. A . Jenks for comments on the manuscript. This note is Article No. 1067 of the Maine Agricultural Experiment Station.

Intramuscular Sarcocystis in Two Beluga Whales and an Atlantic White-Sided Dolphin from the St. Lawrence Estuary, Quebec, Canada

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The anatomy of the male genital system of the beluga whale, Delphinapterus leucas, with special reference to the penis.

The genital organs of four male adult beluga whales and one newborn animal were dissected and the main characteristics are described. As in other species of cetaceans, the testes and the greatest part of the penis are located inside the abdominal cavity. The penis has a sigmoid flexure and belongs to the fibroelastic type with a thick tunica albuginea and a small amount of vascular spaces in the erectile tissue. The prostate gland, found in other cetaceans, was not seen macroscopically, but only small prostate rudiments could be identified histologically. The os penis and the other accessory glands are absent as in other whales.