摘要:

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 patte

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract:There are three major breeding populations of southern elephant seals centered on Macquarie Island, Kerguelen‐Heard Islands and South Georgia‐Antarctic Peninsula. The composition of the diet differs between these populations based on published data from Signy Island and data presented here from Macquarie and Heard Islands. These differences in diet appear to be linked to the location at which seals were sampled ranging from the least Antarctic (Macquarie Island) to the most Antarctic (Signy Island). The major food remains consisted of cephalopod beaks and fish eye lenses. More benthic material was found at Heard Island than at Macquarie Island. The diet at Macquarie Island differed between summer and winter and between young animals and adults. The difficulty in collecting dietary samples of southern elephant seals near their main foraging areas makes the study of the feeding ecology of this species extremely difficult in comparison with other Southern Ocean spec

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

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. InPhyseter catodon(sperm whale) deoxycholic acid constituted 79%, and inKogia 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 an

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract:Elephant seals breed in Patagonia (Península Valdés, Argentina) from late August to early November, reaching peak numbers during the first week in October. Observations of this population over the past ten years yielded similar results. Eighty percent of the pups were born by 2 October. Most (96%) of 663 females marked during three breeding seasons gave birth to a pup. Females stayed on land a mean of 28 d, gave birth 6 d after arrival, nursed their pups for 22 d, and copulated a mean of 2.5 times 20 d after parturition and 2 d before departure. Copulations peaked during the third week in October. Males spent 57–80 d on land fasting and defending harems of up to 134 females (median 11–13 females, depending on year). Most (96%) marked females that gave birth (n= 636) also weaned their pups successfully. Pup sex ratio was unity. Harems were smaller and breeding occurred about three weeks earlier in Patagonia than in other colonies. Thermal conditions, day length and food availability may explain clines in the timing of breeding events between populations, Other parameters of the breeding season for the expanding Patagonia colony are similar to those for declining southern elephant seal populations else

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract:Analytical procedures developed from studies on phocids for relating body morphometrics (length and girth) to mass were applied to 390 Steller sea lions from the Gulf of Alaska and the Bering Sea. The equations relating body volume to mass were significant and had very high correlation coefficients for animals from about 60 to over 900 kg with a standard error of ±0.6% in fitted mass. There was a significant difference in these relationships for female sea lions studied in the 1970s and those examined in the 1980s. The latter sea lions were smaller and/or leaner than those collected in the 1970s

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00425.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract:Two sperm whales tagged with acoustic transponder tags were tracked by sonar during a cruise from 16 to 30 October 1991 in the southeast Caribbean west of Dominica Island. The whales dove to depths of 400–600 m and more, including a dive to 1,185 m and one possibly to 2,000 m. They were tracked for periods of 3–14 h, over distances of 8.5–40 km. The tagged whales were found together four and eight days after tagging, and were tracked simultaneously for 13 h, over 31 km. Whale movements on different days at the surface averaged from 0.68 to 0.82 m/set, with dive descent rates from 0.82 to 1.13 m/set, ascent rates from 0.74 to 1.16 m/set, and horizontal movement during dives from 0.76 to 1.29 m/set. Dives lasted from 18 min to 1 h and 13 min, averaging 33 and 41 min on different days. Every track ended when tag signals became obscured at night by dense biological scatterers concentrated in offshore areas where the whales were diving. Both tagged whales appear to have been males of 15 and 11m, each dominant in different groups; but when together the larger whale was dominant, as evidenced by chases and agonistic vocalizations. The whales did not appear to react to the tags or to the sounds associated with tracking (30, 32, and 36

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00426.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00427.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00428.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00429.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1993.tb00430.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY