Progress report: Results of a long-range captive breeding program for the bottlenose dolphin,Tursiops truncatus and Tursiops truncatus gilli

There have been 36 bottlenose dolphins born in breeding colonies at Sea World, California, and Sea World, Florida, from 1978–1985. Significant features of this successful reproductive program are construction of a compatible breeding colony, early hormonal detection of pregnancy, pre- and postnatal association of inexperienced mothers with experienced females and their calves, and minimized handling of the mothers and calves until the calves are over 1 year of age. Inclusion in the breeding colonies of males old enough to be effective breeders is stressed. Females in the colonies have successfully bred from 8–9 years of age to 23–24 years of age. Calving intervals in the colonies vary from 2 to over 3 years. Calves are born all year round, with some peaking in calving activity in the spring and fall months. Serum progesterone levels greater than 6,000 pg/ml, maintained over a 4–6-week period, are considered indicative of pregnancy. Progesterone levels vary from less than 10,000 to over 50,000 pg/ml during gestation, averaging 25,000 pg/ml. The need for further study of variation in the pattern of progesterone levels during pregnancy is emphasized. A gestation period for Tursiops of 11.5 to 12 months is consistent with our cumulative progesterone data.     

Lymphangiomyomatosis in the Atlantic bottlenose dolphin (Tursiops truncatus).

The first case of lymphangiomyomatosis in a marine mammal is reported from a stranded male Atlantic bottlenose dolphin (Tursiops truncatus). This progressive proliferative disease involved the lungs and the mediastinal and probably mesenteric lymph nodes. An extraordinarily low level of testosterone may have been pathologically significant since all reported cases of this disease in humans occur in females.     

Chemical nature of lachrymal products in the dolphin Tursiops truncatus]

Studies have been made on carbohydrate-protein complex (the ratio of carbohydrate to protein is equal to 1 : 2) in lachrymal products of the dolphin. It was shown that protein component includes 14 amino acids, in which diamino monocarboxylic acids amount to 58%. The ratio of the latter to monoamino dicarboxylic acids is equal to 4.3. Therefore the proteins of lachrymal products are basic ones. This peculiarity of the proteins and the absence of cystein and tryptophan in them indicate that these proteins are represented by histon-like ones, which exhibit high capacity to complex formation. It was demonstrated histochemically, that carbohydrate component of lachrymal reproduct is represented by chondroitin-sulfate B. By thin layer chromatography, neutral monosaccharides (galactose and fucose) were detected, which presumably constitute terminal links of the prosthetic groups.     

Comparative characteristics of the spatial hearing in the dolphin, Tursiops truncatus, and in man

The paper presents data on the directional selectivity of hearing in the bottlenose dolphin as a function of masking noise angle. It has been shown that the hearing system of dolphins is characterised by sharp lowering of masked thresholds depending on the noise going in the high frequency region. The same effect is shown in man, but not so evidently.     

Ultrasonographic imaging of the testis and epididymis of the bottlenose dolphin, Tursiops truncatus aduncas

Eight male bottlenose dolphins, Tursiops truncatus aduncas, underwent examination of the reproductive organs to investigate the use of real-time B-mode ultrasonography in assessment of reproductive status and to establish normal ultrasonographic appearances. Ultrasonography allowed repeatable examinations which were well tolerated by all animals. Ultrasonography was used to examine the testes, epididymides, vasa deferentia, penis, bulbourethral and bulbocavernosal muscles; the prostate was not convincingly distinguished from surrounding muscles. Testicular echopatterns and size differed among individuals. Three distinct testicular echopatterns were discerned and could be used to differentiate males of different reproductive status. Ultrasonographic appearance of the testes provides useful data in assessing the reproductive status of male dolphins.     

Localization of the sensory projection areas in the cerebral cortex of the dolphin, Tursiops truncatus

Using the evoked potential technique, studies have been made on localization of the projectional sensory areas in the cerebral cortex (visual, acoustic and somatosensory) of the porpoise T. truncatus. Distribution of these projectional areas in the porpoise is quite different as compared to that in other mammals. Visual and acoustic areas are shifted to the dorsal part of the hemisphere, all the sensory areas investigated exhibit a direct contact with each other.     

Struvite calculus in the vagina of a bottlenose dolphin (Tursiops truncatus)

On 27 January 2000, a struvite calculus was observed in the vagina during necropsy of a 138-cm-long female bottlenose dolphin (Tursiops truncatus) collected from the Stono River, South Carolina (USA). Vaginal calculi have been reported in other species of cetaceans but not in bottlenose dolphins. Urinary tract infection might have been an underlying cause of the calculus. While urinary tract inflammation was not detected by light microscopic evaluation of sections of the urinary tract, it is conceivable that sufficient time had lapsed following voiding of the calculus through the urethra for urinary tract infection to have resolved. To further define the prevalence and significance of urolithiasis, prosectors of dead stranded marine mammals are encouraged to closely observe their urinary and genital tracts for calculi and to submit them for quantitative analysis.     

Orbital gland structure and secretions in the Atlantic bottlenose dolphin (Tursiops truncatus)

Orbital gland structure of the Atlantic bottlenose dolphin, Tursiops truncatus, was examined at the macroscopic, light microscopic, and electron microscopic levels. The gland completely encircles the ocular globe in a belt-like fashion near the conjunctival fornix but is considerably more developed medially. Duct openings are scattered throughout the fornix and over the surface of the palpebral conjunctiva. Microscopically, the gland has a tubuloalveolar arrangement; alveolar cells contain numerous secretory vesicles which can be interpreted as two structural types by light and electron microscopy. Histochemical staining demonstrates that both types contain glycosaminoglycans. Lipid analysis of the glandular secretion (dolphin tears) shows them to be non-oily and to contain only negligible amounts of cholesterol, triglycerides, phospholipids, and free fatty acids. The secretion is clear, slippery, and viscoelastic and well-adapted to protecting the eye and to reducing frictional forces between the eye surface and surrounding seawater.     

Thirty year retrospective evaluation of pneumonia in a bottlenose dolphin Tursiops truncatus population

Pneumonia is one of the most common causes of morbidity in bottlenose dolphins Tursiops truncatus. To better understand associations of pneumonia with demographics, microbiology, pathology, and histopathology, a retrospective study on 42 dolphins from the US Navy Marine Mammal Program dolphin population was conducted (1980 to 2010). A total of 21 (50%) of the dolphins evaluated had pneumonia confirmed by histopathology. Bacterial and fungal pneumonia was present in 42.9 and 28.6% of cases (9 and 6 cases), respectively, with Staphylococcus aureus as the most common confirmed pathogen (4 cases, 19%). Other pathogens identified as the cause of pneumonia were Cryptococcus neoformans, Erysipelothrix rhusiopathiae, Histoplasma capsulatum, parainfluenza virus, Proteus species, Pseudomonas aeruginosa, and Streptococcus zooepidemicus. Neither sex nor age was a predictor of pneumonia. While many of the infections involved disseminated disease, lungs were consistently the most severely affected organs. The present study demonstrates the high susceptibility of dolphins to respiratory infections. Areas that warrant further investigation include eosinophilic pneumonia, chronic infections, co-infections, and metabolic or iron-storage diseases. There is a continuing need to improve the early diagnosis and effective treatment of pneumonia in dolphins.     

Harderian gland ultrastructure of the black sea bottlenose dolphin (Tursiops truncatus ponticus)

Examination of the Harderian gland structure of the Black Sea bottlenose dolphin, Tursiops truncatus ponticus, at macroscopic, microscopic, and electron microscopic levels shows significant sexual dimorphism. The epithelial cells of male and female glands are different cell types, capable of producing chemically different products. Secretory cells in both sexes contain secretion granules that produce a secretion consisting mainly of proteins and carbohydrates, but thought to be sex-specific in composition. The female glands also contain lipid secretion granules. It is suggested that in the bottlenose dolphin the Harderian gland functions to produce sexually distinct pheromones and may have other physiological activities, e.g., participating in local immunological or endocrine-related reactions. © 1994 Wiley-Liss, Inc.     

Vertebral osteomyelitis and suspected diskospondylitis in an Atlantic bottlenose dolphin (Tursiops truncatus)

A 21-yr-old male Atlantic bottlenose dolphin (Tursiops truncatus) was performing at an aquatic park when it developed a soft tissue swelling anterior to the flukes. Subsequent radiographic evaluation revealed the animal to have vertebral osteomyelitis and suspected diskospondylitis. The case was successfully managed with long-term antibiotic therapy.     

Uterine adenocarcinoma with generalised metastasis in a bottlenose dolphin Tursiops truncatus from northern Patagonia,Argentina

An endometrial adenocarcinoma with areas of squamous differentiation and generalised metastasis was observed in a bottlenose dolphin Tursiops truncatus stranded in northern Patagonia in July 1997. This is the second report of a uterine adenocarcinoma in a free-living cetacean and the first in a Delphinidae. This neoplasm likely compromised reproduction for several years. In addition, the dolphin presented tattoo-like skin lesions and its digestive tract was infested by Anisakis simplex, Pseudoterranova sp., Braunina cordiformis and Corynosoma australe.     

Passive hearing stability in the bottlenose dolphin Tursiops truncatus to low frequency noise spectrum deformation

In behavioral experiments on bottlenose dolphins there was evaluated efficiency of identification of the low frequency noises that represent a certain rhythmical sequence of impulses, at destabilization of their spectra by the method of frequency wobble. Results of the experiments have shown that disturbance of spectral structure at erosion of its discrete components does not lead to a decrease of efficiency of the noise identification, which indicates the greater significance of the time, rather than spectral mechanisms at processing of the complex acoustic signals by the dolphin auditory system.