An overview of cetacean strandings, bycatches and rescues along the western coast of the Taiwan Strait, China: 2010–2015

The analysis of cetacean strandings can provide fundamental information about species diversity and composition in a particular region. The present study collected and analyzed cetacean strandings, bycatches and rescues along the western coast of the Taiwan Strait, China, from 2010 to 2015. In total, 48 records, including 37 strandings, 8 bycatches and 3 rescues, involving 13 known species were collected. Among them, Indo-Pacific humpback dolphins（Sousa chinensis） and finless porpoises（Neophocaena phocaenoides） were the most common species, consisting of 31.3% and 25%, respectively. Notably, 10 out of the 48（20.8%） records were collected from the Pingtan Island and included 3 species of Mysticeti and 4 species of Odontoceti. Finally, we compared the cetacean species composition between the western and eastern coasts of the Taiwan Strait; 31 cetacean species occurred in the Taiwan Strait, indicating a relatively high cetacean diversity in this region. Systematic field surveys are urgently needed to explore the cetacean species composition, population stock and the related habitat status in the Taiwan Strait, which may improve conservation management in the future.

Towards a Standardized Approach of Cetacean Habitat: Past Achievements and Future Directions

The understanding of what habitat means for an organism as well as the underlying factors driving patterns of habitat use is still unknown for many species. Cetacean habitat has been described using a range of methodologies and variables measured over various temporal and spatial scales?that are often author-dependent. However, in order to develop an objective and sound understanding of what habitat actually means for cetaceans, a standardized approach needs to be developed. Here, after briefly reviewing the fundamental differences between terrestrial and marine habitats, we highlight the difficulty in defining a marine habitat, with a special focus on marine mammals. We subsequently provide six recommendations by which future cetacean habitat studies might be approached. This recommended approach aims to amend the way in which we think about and undertake investigations into cetacean habitat. It is believed that through this broadened approach, future cetacean habitat studies will increase our understanding of underlying driving factors of cetacean habitat, rather than just describing distribution patterns. Finally, it is stressed how the proposed approach will be more directly applicable within management frameworks and of benefit to conservation initiatives.

An overview of research efforts to understand the effects of underwater sound on cetaceans

Cetaceans are aquatic mammals living in an environment that is more suited for hearing than vision.As such,their sensory systems largely utilize acoustic cues for navigation,communication,foraging,and predator avoidance.However,the elevation of underwater sound levels from increased human activities has adversely affected cetaceans’use of sound to perform vital life functions.To address those impacts,scientific studies have been conducted to understand the behavioral,psychoacoustical,physiological,and physical responses by cetaceans that have been exposed to anthropogenic sound.These studies range from captive experiments involving auditory thresholds and noise-induced threshold shifts,to field observations of behavioral disturbance from sound exposure,to post-mortem examinations of physical manifestations in stranded animals.Over the years,results from these studies have assisted regulatory agencies in developing a series of criteria and thresholds for cetacean conservation and management around the world.This paper provides a high-level overview of worldwide research efforts that have been dedicated to understanding the effects of underwater sound on cetaceans.The review is not intended to be exhaustive but rather to capture major efforts and significant findings in this field.In addition,the review excludes synthesis studies and modeling exercises that do not involve direct research on target species.

鲸类消化道微生物研究进展与展望

作为宿主的“第二套基因组”,消化道微生物与宿主的营养吸收和免疫抵御等功能紧密相关。与陆生哺乳动物相比,海洋哺乳动物鲸类的消化道微生物是目前国内外关注较少的研究领域。已有研究表明,鲸类消化道微生物极易受到食物和栖息地环境等因素的影响,然而现阶段研究手段以基于粪便样品进行高通量测序为主。本文对鲸类消化道微生物的研究手段、群落结构、功能特征和调控策略等方面的进展进行总结和分析,并对未来发展方向提出展望和建议。

Cetacean occurrence and diversity in whale-watching waters off Mirissa,Southern Sri Lanka

Scientific information is vital to the conservation of cetaceans and the management of whale-watching activities.The southern coastal waters of Sri Lanka are near a narrow continental shelf and biologically abundant in cetacean species.Although the occurrence of cetaceans has been investigated in certain waters of Sri Lanka,few surveys have been conducted along the southern coast.To fill this gap,we conducted boat-based surveys from January to May 2017 to investigate the occurrence,diversity,and behavior of cetaceans in the waters off Mirissa,covering a survey area of 788.9 km2.During 55 survey days,we recorded a total of 242 cetacean sightings and identified at least 9 species(3 mysticetes and 6 odontocetes).The blue whale was the most common mysticete species(167 of 174 mysticete encounters),followed by the Omura’s whale(4 of 174)and Bryde’s whale(3 of 174).The spinner dolphin was the most common odontocete species(28 of 68 odontocete encounters),followed by the sperm whale(18 of 68),common bottlenose dolphin(13 of 68),short-finned pilot whale(5 of 68),melon-headed whale(2 of 68),and killer whale.Blue whales and sperm whales exhibited a clear preference for outer shelf and high slope areas,and blue whales were observed feeding along these waters.The present study provides near-baseline information on cetacean occurrence and diversity in whale-watching waters off southern Sri Lanka,and highlights the urgent need for proper management strategies for whale-watching activities.

A pioneering survey of deep-diving and off-shore cetaceans in the northern South China Sea

A pioneering boat-based survey was conducted in 2019,to gather baseline information regarding the presence,composition,relative abundance,and spatial distribution of deep-diving and off-shore cetaceans in the northern South China Sea(SCS).A total of 27 sightings comprising at least 8 cetacean species were recorded during the 13-day survey,including 5 deep-diving species(i.e.Risso’s dolphin[Grampus griseus],short-finned pilot whale[Globicephala macrorhynchus],sperm whale[Physeter macrocephalus],Cuvier’s beaked whale[Ziphius cavirostris],and an unidentified beaked whale[either the ginkgo-toothed beaked whale,Mesoplodon ginkgodens,or Deraniyagala’s beaked whale,Mesoplodon hotaula]),as well as 3 off-shore dolphins(i.e.pantropical spotted dolphin[Stenella attenuate],striped dolphin[Stenella coeruleoalba],and Fraser’s dolphin[Lagenodelphis hosei]).With the exception of pantropical spotted dolphins,all other species were sighted and recorded at sea in the northern SCS for the first time.The pantropical spotted dolphin was the most frequently sighted species,comprising 30%of the total sightings.Deep-diving cetaceans were mainly sighted in the northern Xisha Archipelago,whereas off-shore dolphins were distributed across the survey area.The pantropical spotted dolphin was observed in aggregations of more than 100 individuals and nearly all encountered species included calves;these findings suggested that the survey area functions as an important feeding and calving ground for various cetacean species.This pioneering survey provides fundamental information regarding cetacean fauna in the northern SCS and highlights the need to strengthen research and conservation efforts concerning these species.

Cetacean morbillivirus: A Land-to-Sea Journey and Back?

Cetacean morbillivirus(CeMV),the most relevant pathogen impacting the health and conservation of several already threatened cetacean populations worldwide(Van Bressem et al.2014),has shown in recent years an apparently increased tendency to cross"interspecies barriers"(Jo et al.2018a),thereby giving rise to disease and mortality outbreaks in free-ranging dolphins and whales(Mazzariol et al.2016,2017;Jo et al.2018b).

Annotated checklist and fisheries interactions of cetaceans in Togo, with evidence of Antarctic minke whale in the Gulf of Guinea

Based on strandings and captures,9 cetacean species,including 6 odontocetes and 3 mysticetes,are document-ed(photos and specimens)in Togo’s coastal waters(newly-recorded species marked with an asterisk):Antarc-tic minke whale(Balaenoptera bonaerensis*),Bryde’s whale(Balaenoptera brydei or B.edeni),humpback whale(Megaptera novaeangliae),sperm whale(Physeter macrocephalus),pygmy sperm whale(Kogia brevi-ceps*),short-finned pilot whale(Globicephala macrorhynchus*),pantropical spotted dolphin(Stenella attenu-ata*),common bottlenose dolphin(Tursiops truncatus)and common dolphin Delphinus sp.An anecdotal sight-ing record for killer whale(Orcinus orca)is considered reliable.The lack of Sousa teuszii records in Togo is consistent with its apparent contemporaneous absence in Ghana.The B.bonaerensis specimen,entangled in a purse seine set on small pelagics,is a first record for the Gulf of Guinea.The occurrence of this Southern Ocean species north of the equator underscores the severe gaps in our understanding of cetacean distribution off west-ern Africa.The majority of artisanal fishermen operating in Togolese coastal waters are of Ghanaian origin and are thought to promote trade and consumption of cetacean bushmeat.Because captures are illegal,enforced with some success in the main fishing centers,covert landings of cetaceans are exceedingly difficult to moni-tor,quantify or sample.Concern is expressed about pollution of Togo’s coastal waters with heavy metals due to phosphorite mining and export from the coastal basin near Hahotoéand Kpogamé.

Oxygen isotopic variations in modern cetacean teeth and bones： implications for ecological, paleoecological, and paleoclimatic studies

The oxygen isotope ratios(d18O) preserved in marine sediments have been widely used to reconstruct past ocean temperatures. However, there remain significant uncertainties associated with this method, owing to assumptions about the d18 O of ancient seawater which affects the temperature inferred from sediment d18 O records. In this study, oxygen isotope compositions of phosphate in teeth and bones from five different modern cetacean species, including sperm whale, pygmy sperm whale, short-finned pilot whale, killer whale, and Cuvier's beaked whale, and three fossil whales were determined. The data were used to assess whether the oxygen isotope ratios of biogenic phosphate(d18Op) from cetaceans are a reliable proxy for the oxygen isotopic composition of ocean water(d18Ow). The d18 Opvalues of modern cetaceans range from15.5 % to 21.3 %, averaging(19.6 %± 0.8 %)(n = 136).Using a greatly expanded global cetacean d18 Opdataset, the following regression equation is derived for cetaceans:d18Ow= 0.95317(±0.03293) d18Op- 17.971(±0.605),r = 0.97253. The new equation, when applied to fossil teeth and bones, yielded reasonable estimates of ancient seawater d18 Owvalues. Intra-tooth isotopic variations were observed within individual teeth. Among the selected species, the killer whale(O. orca) has the lowest d18 Opvalues and the largest intra-tooth d18 Opvariation, reflecting its habitat preference and migratory behavior. The results show that oxygen isotope analysis of phosphate in cetacean teeth and dense ear bones provides a useful tool for reconstructing the oxygen isotopic composition of seawater and for examining environmental preferences(including migratory behavior)of both modern and ancient whales.

基于水声学频差技术的镇江长江豚类省级自然保护区鱼类资源时空特征

为掌握镇江长江豚类省级自然保护区鱼类资源现状,于2020年春季(4月)和秋季(9月)利用水声学频差技术和网具调查方法同步开展鱼类资源调查,评估调查江段鱼类资源时空特征。水声学调查结果表明,调查江段鱼类资源密度均值为(0.094±0.183)尾/m^(2),鱼类单体目标强度(Target strength,TS)均值为–(57.33±5.69)dB,主要分布在–62.5-–50.5 dB,随着水深的增加,TS逐渐增大;网具调查结果表明,调查江段共采集鱼类758尾、53.53 kg,鉴定鱼类种类达48种,其中以鲤形目(Cypriniformes)鱼类占优,中上层鱼类群体数量和质量占比分别为36.15%和66.12%,长江江豚饵料鱼类(体长小于20 cm、体高小于6 cm、体重小于100 g的中上层鱼类)数量和质量占比分别为23.22%和8.72%。在时间特征上,4月和9月鱼类资源密度差异不显著(P>0.05),4月鱼类TS均值小于9月,且4月鱼类平均规格小于9月。在空间特征上,鱼类资源主要分布于和畅洲北汊和焦北滩附近水域,中上层鱼类资源相对较多,且4月鱼类资源分布相对更集中。水声学频差技术能够有效地剔除水域环境中的浮游生物信号和背景噪声信号,对于长江流域鱼类资源声学评估具有借鉴意义。研究结果可为准确评估该保护区长江江豚饵料鱼类资源,支撑长江江豚就地保护,并为长江下游鱼类资源养护工作提供科学依据。

我国金枪鱼围网渔业对鲸豚类误捕的影响分析

鲸豚类是中西部太平洋生态系统的顶级捕食者,近年来,金枪鱼围网渔业对鲸豚类的误捕是海洋哺乳动物保护中最令人关注的热点之一。为探讨自由鱼群和人工集鱼装置作业对鲸豚类误捕的影响,提出对鲸豚类保护的建议,笔者根据2016—2019年我国金枪鱼围网渔业在中西部太平洋海域(N 10°~S 13°,E 144°~W 149°)的生产数据,探讨自由鱼群和人工集鱼装置2种作业方式在不同区域、时间段、月份和年份下对鲸豚类误捕的影响。结果显示:中西部太平洋鲸豚类的误捕主要发生在基里巴斯专属经济区;不同时间段下,自由鱼群作业下误捕鲸豚类分布较平均,且差异不显著(P>0.05),人工集鱼装置作业下误捕鲸豚类主要集中在16:00—19:00,差异显著(P<0.05);1、7月和11月的鲸豚类误捕量较高,且自由鱼群和人工集鱼装置作业下不同月份鲸豚类误捕均差异不显著(P>0.05);自由鱼群和人工集鱼装置作业造成的鲸豚类平均死亡率分别为43.04%和33.33%,2种作业方式对鲸豚类死亡率的差异不显著(P>0.05),不同物种误捕死亡率受2种作业方式的影响存在差异性。本研究结果可为中西部太平洋鲸豚类养护管理提供科学参考。

中西太平洋延绳钓渔业鲸类兼捕的空间变化及其环境影响

鲸类物种和延绳钓渔具之间的相互作用是一种全球性现象,该相互作用威胁到鲸类物种的保护和延绳钓渔业的经济可行性。尽管认识到鲸类兼捕问题,但很少对其影响进行全面评估。根据中西部太平洋渔业委员会(WCPFC)科学机构提供的2013—2019年期间的观察员数据,利用广义可加模型(GAM)分析金枪鱼延绳钓渔业中兼捕的鲸类与时空和环境因子的关系。结果表明:在中西太平洋海域,共兼捕260头鲸类,隶属于2目5科19种,主要的兼捕对象是伪虎鲸(Pseudorca crassidens)、瓶鼻海豚(Tursiops truncatus)、里氏海豚(Grampus griseus)、短鳍领航鲸(Globicephala macrorhynchus)、糙齿海豚(Steno bredanensis)等。GAM模型对BPUE的总偏差解释率为71.7%,经度的贡献率最大为34.3%,各预测变量的相对重要性分别为经度>海表温度>叶绿素a浓度>纬度>单位捕捞努力量渔获量(CPUE)。鲸类兼捕主要由空间和环境因子所决定,其中海表温度主要影响鲸类的相对丰度,叶绿素a浓度影响鲸类的分布。未来,渔业管理者可以利用环境因子作为鲸类物种热点指标,将重点放在鲸类物种与延绳钓渔业的互动海域,以更合适的方式实施鲸类兼捕的减缓措施。

鲸豚动物吸附式声学行为记录器综述

经过数千万年的进化,鲸豚动物依靠发达的声呐系统在水下实现捕猎、探测、通信、定位与导航等行为。为探索鲸豚动物声呐机理,需要深入挖掘鲸豚发声行为。近年来,自容式的声学行为记录器已成为重要的观测途径。自容式声学记录器可附着于鲸豚动物,长期获取各类声学信号,利用多源传感器从多个角度观测动物行为状态与环境信息。文章介绍了鲸豚动物吸附式声学行为记录器的系统设计思路,描述了获取数据的后置处理方法,并进一步梳理国内外研制的发展脉络,展望了声学行为记录器在发声特性研究、生物学、生态学等多领域的应用前景,并对下一步技术突破重点提供参考。

木孜塔格—鲸鱼湖断裂带特征、演化及其意义

通过对东昆仑山木孜塔格—鲸鱼湖断裂在青藏高原北部陆内变形过程中形成的构造形迹、沉积建造、新生代火山活动、地球物理场变化综合研究,以野外第一手资料重建该过程的演化历史,认为木孜塔格—鲸鱼湖断裂是青藏高原北部陆内变形过程遗留的重要地质证据,卫星遥感图像上显示极为明显,它具有重要的区域构造意义。首先,发育大规模由北向南的叠瓦式逆冲推覆构造,新近纪由南向北沿构造带分布着东西向平行排列的"堑垒"相间式断陷盆地;其次还见有大量中性火山岩浆沿该断裂及其次级断裂溢出分布,成因分析表明其来源于陆内俯冲作用;第三,该断裂的走向延伸线上现今还发生较大规模的地震活动。综合分析表明,该断裂作为与柴达木地块南部构造边界断裂彼此平行的南东东向大型走滑断裂带,具有左行走滑构造分量,应是青藏高原北缘亚洲大陆向北东逃逸的主要断裂系统。

PCR扩增Sry基因进行鲸类动物性别的鉴定

哺乳动物Y染色体短臂上的Sry基因决定雄性发育方向。本研究参照哺乳动物Sry基因保守区序列设计引物 ,以非性别特异性的线粒体DNA细胞色素b基因作为阳性对照 ,用PCR扩增江豚、长喙真海豚等鲸类动物的Sry基因片断并对其进行凝胶电泳分析来鉴定鲸类动物的性别。通过此方法对 87个已知性别鲸类动物标本的检验 ,结果完全正确 ,并进一步应用此方法成功地完成了另外 33个未知性别鲸类标本的性别鉴定。由此建立了一套简单、快速。

鲸类c-mos基因的序列变异性及在系统发生分析中应用的初步研究

通过猪等的c -mos基因保守区序列设计了用于扩增鲸类c -mos基因的引物。应用此引物扩增并测定了齿鲸类 5个科 12个种 5 4 6bp的c -mos基因编码区序列。结果表明鲸类的c -mos基因遗传变异水平较低。在系统发生重建中 ,同科的物种聚为单系 ,但不能很好地解决科下亚科间的关系 ,提示c -mos基因仅适于鲸类科级以上阶元的系统发生研究。

中国沿岸小型鲸类误捕情况的调查

报道了１９９４ ～１９９５ 年对中国沿岸小型鲸类误捕情况的调查结果．调查表明，有误捕记录的小型鲸类主要有５ 种，即江豚（ Ｎｅｏｐｈｏｃａｅｎａ ｐｈｏｃａｅｎｏｉｄｅｓ） 、长喙真海豚（ Ｄｅｌｐｈｉｎｕｓ ｃａｐｅｎｓｉｓ） 、瓶鼻海豚（ Ｔｕｒｓｉｏｐｓｔｒｕｎｃａｔｕｓ） 、点斑原海豚（Ｓｔｅｎｅｌｌａ ａｔｔｅｎｕａｔａ） 和伪虎鲸（ Ｐｓｅｕｄｏｒｃａ ｃｒａｓｓｉｄｅｎｓ） ，其中以江豚的误捕率最高．１９９４ 年在山东、浙江、福建、广东、海南省和广西壮族自治区沿岸渔业误捕的小型鲸类约３０４５ ±２１２０ 头，其中江豚的误捕量约２１３２ ±１４８４ 头．误捕小型鲸类的渔具主要有拖网、刺网和张网．中国沿岸没有专门捕鲸的渔业方式．误捕的小型鲸类在沿岸居民的生活中不占重要地位，它们大部分被丢弃或廉价出售．目前尚不知道误捕对中国水域小型鲸种群影响的程度，但可能是造成数量下降原因之一．

台湾海峡厦门-东山水域瓶鼻海豚的种群密度、分布和误捕研究

台湾海峡厦门东山水域瓶鼻海豚 ( Tursiopsaduncus)的种群密度约为 0 .0 4 36± 0 .0 2 86头 /km2 ,该水域南部瓶鼻海豚的发现率高于中部和北部。问卷调查和随船出海调查表明围网作业发现和误捕小型鲸类的频率要高于拖网 ,同时拖网又高于刺网。调查期间从东山港记录到的误捕致死的 2 0头小型鲸类中 ,6头 (占 30 % )为瓶鼻海豚 ,分别由拖网和围网捕获。需要开展对当地渔民的宣传教育和加强台湾海峡瓶鼻海豚等小型鲸类的种群生物学和保护生物学的研究。

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。