厦门港的中华白海豚 Ⅴ.对水生生活的适应

1994～ 1 999年 ,在厦门港 2 0个中华白海豚监视站进行观测 ,实施了87航次跟踪拍照 ,对 7头幼仔和 6头成体标本进行了现场测量和解剖。第二次下水的中华白海豚既具备哺乳动物纲最基本的特征 ,也在运动 (游泳 )、水下生殖和哺乳、呼吸和感觉 (包括声纳 )等方面产生了一系列对水环境的适应。     

码头施工中几个细节问题的建议

通过威海港码头工程施工实践,提出了卸荷板下棱体抛石和水下整体平面施工方法,还就系船柱和护舷预埋螺栓的施工标准提出了建议。     

厦门港的中华白海豚Ⅲ.牙齿和年龄

对厦门５头中华白海豚成体和６头哺乳期的幼仔,进行齿的形态、齿式、内部构造和磨损情况的研究;根据齿的切片判断年龄,５头成体９～３０岁,年龄大小和体表颜色及齿的磨损程度密切相关。出生后的幼仔齿包埋在齿龈中,其齿数、齿式和成体一样。     

伊洛瓦底海豚被追逐时回声定位信号特征变化的初步分析

本文的研究基于文莱湾浅水域的一头野生伊洛瓦底海豚水声定位信号的调查数据。在记录期间,有一艘渔船突然开启发动机,惊扰了其附近的一头伊洛瓦底海豚,接着渔船开始两次连续追逐海豚。这期间海豚回声定位信号的变化情况被记录下来。当伊洛瓦底海豚受惊吓被追逐时,信号的声压级、每分钟嘀嗒声信号串的发生次数、每个嘀嗒声信号串中的脉冲个数和平均脉冲间隔都发生了相应的变化。平均的脉冲间隔在事件发生的瞬间立即增大,并在追逐期间呈现轻微下降趋势。脉冲间隔的增大对应着探测距离的增加,代表着海豚对未知区域的探索能力,制约着它的逃离速度。数据记录结果的分析表明,伊洛瓦底海豚会根据外界干扰对发出的回声定位信号进行调整,改变自己对潜在危险的探查能力。分析结果同时提醒我们需要随海豚生存环境的噪声进行管理,避免突然的发动机操作或者追逐它们。     

Toothed whales in the northwestern Mediterranean: insight into their feeding ecology using chemical tracers

Risso’s dolphins, pilot whales and sperm whales rarely strand in the northwestern Mediterranean. Thus, their feeding ecology, through the analysis of stomach contents, is poorly known. The aim of this study was to gain further insight into the segregation/superposition of the diet and habitat of Risso’s dolphins, pilot whales and sperm whales using chemical tracers, namely, stable isotopes (δ¹³C, δ¹⁵N) and organochlorines. Significantly different δ¹⁵N values were obtained in Risso’s dolphins (11.7 ± 0.7‰), sperm whales (10.8 ± 0.3‰) and pilot whales (9.8 ± 0.3‰), revealing different trophic levels. These differences are presumably due to various proportions of Histioteuthidae cephalopods in each toothed whale’s diet. Similar δ¹³C contents between species indicated long-term habitat superposition or corroborated important seasonal migrations. Lower congener 180 concentrations (8.20 vs. 21.73 μg.g⁻¹ lw) and higher tDDT/tPCB ratios (0.93 vs. 0.42) were observed in sperm whales compared with Risso’s dolphins and may indicate wider migrations for the former. Therefore, competition between these species seems to depend on different trophic levels and migration patterns.     

Photogrammetry using in-field calibration: a non-invasive tool for predicting sex and life stages tested on Hector's dolphins in the wild

Accurate data on sex and life stage are essential for building realistic population models, which in turn are essential for sustainable conservation management. This case study develops and validates an improved photogrammetry method that allows for in-field calibration. The method was used to measure Hector's dolphins’ dorsal fins in the wild. Seven independent measurements of one dolphin resulted in a coefficient of variation of 1.39% for fin base length and 2.33% for fin height. Test measurements on shore at different distances and angles resulted in a mean error smaller than 1% up to a distance of 10?m and an angle of 40°. Dorsal fin dimensions from necropsied Hector's dolphins were analysed to evaluate the potential of predicting sex and life stage based on a dorsal fin measured in the wild. Dorsal fin shape was significantly related to sex. However, sex estimations based on this model turned out to be not accurate enough to replace traditional sexing methods for Hector's dolphins. Fin base length was significantly related to life stage for females. Estimations based on this model appear to be accurate.     

Abundance and distribution of avian and marine mammal predators of sardine observed during the 2005 KwaZulu-Natal sardine run survey

Opportunistic observations to determine the relative abundance and distribution of marine mammal and seabird predators of sardine Sardinops sagax were carried out during a dedicated multidisciplinary research survey off the South African east coast in June and July of 2005 that was timed to coincide with the annual sardine run. Associations between different predator species, between predators and clupeoids, and between predators and oceanographic variables, were examined. Species’ distributions were primarily separated by latitude and distance from shore. Bryde's whale Balaenoptera edeni, African penguin Spheniscus demersus, Cape cormorant Phalacrocorax capensis and West Coast round herring Etrumeus whiteheadi were predominantly found in the cool southern part of the survey region. Peak sardine run activity occurred within 4 km of shore at the northward limit of a strip of cool water (<21 °C) stretching along the East Coast. The principal predators associated with this activity were common dolphins Delphinus capensis and Cape gannets Morus capensis, and their nearshore distribution was associated with sardine and East Coast round herring E. teres. Few clupeoids were encountered along the KwaZulu-Natal continental shelf, although patches of high sardine abundance were recorded near the shore immediately south of Durban. It is clear that during the 2005 survey the sardine run terminated in this region, probably as a result of the nearshore intrusion of warm water from the Agulhas Current.     

海豚妊娠分娩哺育期间的观察及护理

野生海豚的妊娠、分娩及哺育过程很难进行科学、系统地观察监测，人工饲养海豚的繁殖情况却屡见报道。我馆于2003年3月20日从日本购进6头雌性太平洋瓶鼻海豚(Tursiops truncatus aduncus)，其中1头编号为“270”的海豚于2003年6月19日顺利产下1头雄性幼仔，作者对其母子进行每天24h看护达2周之久。此后的1年中，幼仔生长良好。本文就海豚“270”的妊娠、分娩及哺育过程进行详细描述，并将工作人员对“270”母子采取的护理措施作一具体说明。     

Organohalogen contaminants in striped dolphins (Stenella coeruleoalba) from Japan: Present contamination status, body distribution and temporal trends (1978-2003)

Organohalogen contaminants including PCBs, DDTs, CHLs, HCHs, HCB, PBDEs and HBCDs were determined in striped dolphins (Stenella coeruleoalba) found stranded at Gogo-shima (n = 6, 2003) and collected from Taiji (n = 15, 1978-1992) in Japan. All target compounds were significantly detected in all the specimens, indicating ubiquitous contamination of oceanic cetaceans in northwest Pacific Ocean. Examination of body distribution of organohalogens in the six specimens from Gogo-shima showed no significant difference in concentrations among the analyzed tissues, except for brain, which had lower levels possibly due to the existence of blood-brain barrier. For evaluating temporal trends, archived blubber samples of adult male stripped dolphins collected in 1978, 1979, 1986 and 1992 were analyzed. Concentrations of PCBs, DDTs and HCHs did not change significantly during 1978-2003. In contrast, remarkable increasing trends of PBDEs and HBCDs were observed, suggesting growing consumption in Japan and surrounding countries in recent years.     

Interelement relationships and age-related variation of trace element concentrations in liver of striped dolphins (Stenella coeruleoalba) from Japanese coastal waters

Concentrations of 19 trace elements (V, Cr, Mn, Fe, Co, Cu, Zn, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, Hg, and Pb) were determined in the liver of the striped dolphins (Stenella coeruleoalba) collected around Japan during 1977–1982 to examine the sex difference, age dependence, and interrelationships among trace elements. Tissue distribution of trace elements was also investigated in one adult and one fetus specimens. Generally, concentrations of Se, Sr, Ag, Cd, Cs, Ba, Hg, and Pb were higher in the tissues of adult than those of fetus, whereas the opposite trend was observed for Cr and Tl. There were no significant sex differences in the trace element levels in the liver. Significant positive correlations between age (0–26.5 years) and hepatic concentrations were found for Ag, Se, Hg, V, Fe, Pb, and Sr, suggesting their age-dependent accumulation in the liver. In contrast, hepatic concentrations of Mn and Zn decreased with age. Significant positive relationships were observed between Se, and Hg, Ag, V, Fe, and Sr in the liver.