GROWTH IN YOUNG GRAY WHALES (ESCHRICHTIUS ROBUSTUS)

Mean body lengths of gray whale calves were found to increase linearly from 4.6 m at birth to 7 m by weaning at six mo. After weaning, rates of length increase diminish, with calves reaching 8 m by one yr of age and 9 m by two yr. Evaluations of the weights of nine gray whales as functions of their measured lengths and girths reduce the emphasis placed on fast-induced seasonal variations in girth by Rice and Wolman (1971). From birth weights of just under one metric ton, calves double their weights by three mo of age and double again by weaning at six mo.     

CLICK CHARACTERISTICS OF NORTHERN BOTTLENOSE WHALES (HYPEROODON AMPULLATUS)

Sounds produced by northern bottlenose whales ( Hyperoodon ampullatus ) recorded in the Gully, a submarine canyon off Nova Scotia, consisted predominately of clicks. In 428 min of recordings no whistles were heard which could unequivocally be attributed to bottlenose whales. There were two major types of click series, initially distinguished by large differences in received amplitude. Loud clicks (produced by nearby whales socializing at the surface) were rapid, with short and variable interclick intervals (mean 0.07 sec; CV 71%). The frequency spectra of these were variable and often multimodal, with peak frequencies ranging between 2 and 22 kHz (mean 11 kHz, CV 59%). Clicks received at low amplitude (produced by distant whales, presumably foraging at depth) had more consistent interclick intervals (mean 0.40 sec, CV 12.5%), generally unimodal frequency spectra with a mean peak frequency of 24 kHz (CV 7%) and 3 dB bandwidth of 4 kHz. Echolocation interclick intervals may reflect the approximate search distance of an animal, in this case 300 m, comparable to that found for sperm whales. The relationship between click frequency and the size of object being investigated, suggests that 24 kHz would be optimal for an object of approximately 6 cm or more, consistent with the size range of their squid prey.     

ELEMENTS IN LIVER TISSUES OF BOWHEAD WHALES (BALAENA MYSTICETUS)

Livers from 20 bowhead whales taken in subsistence hunts at Barrow, Alaska, were analyzed for essential and non-essential elements. Concentrations of essential elements were similar to those found in other cetaceans. Non-essential element concentrations were generally comparable to other baleen whales and very low compared to most odontocetes. One deviation from this pattern was a relatively high level of hepatic cadmium that may be related to specific dietary factors of this krill-dependent species. No sex-related differences were found in element concentrations. Hepatic cadmium and mercury increased with animal length, and significant positive interelement correlations were found between copper/zinc and mercury/selenium. We found a mercury-toselenium ratio much lower (1:40) than the frequently reported ratio of one to one. The data suggest that further studies of the postulated mercurydetoxifying role of selenium are warranted.     

ASPECTS OF GROWTH IN CAPTIVE KILLER WHALES (ORCINUS ORCA)

Morphometrics from 25 captive killer whales (11 captive-born) were collected at SeaWorld parks from 1984 to 1995 to determine age-specific growth parameters. For sexes combined, the body-volume index was the most accurate predictor of body weight. However, predicting weight from total length was appropriate, although it may underestimate weight of pregnant animals. Among captive-born calves, a Gompertz model was the best predictor of weight and length at age. Estimates for length and weight at birth were done using data from in utero and neonatal calves. For ages 1-5 yr, models indicate that males grew in both weight and length at slower rates. Growth rates in males may surpass those of females at approximately 5-6 yr of age.     

BILIARY BILE ACID COMPOSITION OF THE PHYSETERIDAE (SPERM WHALES)

Abstract: The bile acid composition of bile obtained from the hepatopancreatic ducts of three species of sperm whales (Cetacea: Physeteridae) was investigated. Bile acids were isolated by adsorption chromatography and analyzed by sequential HPLC, SIMS, and GLC-MS. In each species the dominant bile acids were deoxycholic acid (a secondary bile acid formed by bacterial 7α-dehydroxylation of cholic acid), and chenodeoxycholic acid (a primary bile acid) which together composed more than 86% of biliary bile acids in all three species. In Physeter catodon (sperm whale) deoxycholic acid constituted 79%, and in Kogia breviceps (pygmy sperm whale) it was 61% of biliary bile acids. The sperm whale, which differs from other whales in having a remnant of a large intestine, is the second mammal identified to date in which deoxycholic acid is the predominant bile acid. The high proportion of deoxycholic acid indicates that in the Physeteridae, anaerobic fermentation occurs in its cecum, and that bile acids undergo enterohepatic cycling. Also found were minor proportions of cholic acid, as well as bacterial derivatives of chenodeoxycholic acid (ursodeoxycholic acid, lithocholic acid, and the 12β-epimer of allo-deoxycholic acid). Bile acids were conjugated with taurine in all species; however, in the sperm whale ( Physeter ) glycine conjugates were present in trace proportions. The bile acid hydroxylation pattern (12α- but not 6α-hydroxylation), lack of primary 5α- (allo) bile acids, and presence of glycine conjugated bile acids suggests the possibility that sperm whales originated from ancient artiodactyls.     

PATTERN SIMILARITY IN SHARED CODAS FROM SPERM WHALES (PHYSETER CATODON)

Abstract: Codas (patterned click sequences) produced by sperm whales ( Physeter catodon ) were recorded during four research cruises in the southeast Caribbean. Two coda patterns comprised more than 50% of the codas analyzed from 46 h of recording. These two patterns were called "shared" codas because they were produced by numerous whales throughout the area, both as repeated sequences by individual whales, at times simultaneously by two or more whales, and occasionally in overlapping series. Analyses of both the absolute timing and the relative timing of click intervals indicate equivalent variability in the temporal patterns of similar shared codas, whether produced by the same or different whales. The shared codas appear to have a function that is different from individual identification as hypothesized previously for some coda patterns.     

TEMPORAL VARIABILITY IN FEATURES USED TO PHOTO-IDENTIFY HUMPBACK WHALES (MEGAPTERA NOVAEANGLIAE)

Photographs of 99 humpback whales of known age were analyzed to assess the temporal variability and recognizability of individually distinctive fluke and dorsal fin features used for photo-identification. Stable features tended to be morphological in nature (dorsal fin shape and edges, the trailing edge of the fluke, and the raised bumps on the caudal peduncle termed "knobs"). Transitory features typically were superficial marks (scarring, scratching, and pigmentation). The variability of several features was found to be age-dependent as well. Young animals sometimes experienced substantial change to their fluke coloration patterns, though this feature stabilized with age. Dorsal fin edges and fluke serration peaks tended to undergo more change in males than in females, with most changes occurring following sexual maturation. Peduncle knobs were the most stable feature, with no documented change in any age interval. Given the extreme stability (and hence recognizability) of dorsal fin shape and peduncle knobs, we suggest that photographs combining the dorsal fin and the caudal peduncle provide the most consistent way to reidentify humpback whales, particularly calves following weaning.