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.

Bycatch of Shrimp Fishery in the West Coast of Madagascar： Case of Otolithes argenteus （Cuvier, 1830）

An increasing interest of the economic operators on the bycatch of shrimp fishery endangers bycatch species to over-exploitation risks. This study provides a better knowledge regarding to the current status of one major component of the bycatches Otolithes argenteus （O. argenteus） caught in the shrimp fishery area along the West coast of Madagascar using the morphometric analysis. Individual body weight and body measurement were carried out on 565 specimens collected from the sale＇s society of seafood （SOPROMER） in the Capital city. Results show a high proportion of small fishes like as immature young individuals. A ＂negative allometry＂ growth type within the juveniles to become ＂isometric allometry＂ for the adult, large size was observed. Marine environment is favorable to the development for the whole population of the O. argenteus species. The morphometry approach helped to better understanding of the characteristics and the operating status of the O. argenteus population thus constitute as a tool in establishing a sustainable fisheries management strategy in Madagascar.

Corollary of Marine Eco-system Sustainability by Addressing the Issues of Bycatches

The issue of bycatch in the fisheries sector has been a major concern for the marine biologists over few decades in terms of conservation of marine eco-system and sustainability of the fisheries sector and marine biodiversity.As far as the concept of Bycatch is concerned,these are the unwanted species having less commercial importance,which in most of the cases disposed into the seas onboard or are caught during fishing.The article discusses the social,economic,cultural,and environmental impacts in addressing the issue of bycatch.The concern regarding bycatch is relatively new in the horizon in Indian perspective though it is often considered a major issue faced by developed nations since long.The problem of bycatch poses a serious threat to livelihoods and food security as it acts as a precursor to depletion of the food sources for local consumption with adverse social,economic,cultural,and environmental impacts.The adverse effects of by-catch can be mitigated through commercialisation of bycatch and making profits from the sale of bycatch,opening up of new markets for bycatch species or products,uses of bycatch as fishmeal and application of bycatch reduction devices(BRDs).Reorientation of the present monitoring system to collect fisheries data,strengthening technical know-how,bringing effective policy intervention,efficient co-management,and sincere and honest efforts in reducing bycatch and discards may provide a considerable impact towards sustainability of marine eco-system.

Smaller bar spacings in a Nordmøre grid reduces the bycatch of redfish(Sebastes spp.)in the offshore Northern shrimp(Pandalus borealis)fishery of eastern Canada

The offshore Northern shrimp(Pandalus borealis)bottom trawl fishery in eastern Canada currently uses 22 and 28 mm bar spacing Nordmøre grids to limit bycatch from using small mesh codends.However,a recent rebound of juvenile redfish(Sebastes spp.),that can pass through the grids,has greatly increased bycatch.To address this concern,this study investigated the effectiveness of 17 and 15 mm bar spacing Nordmøre grids in a twin-trawl(paired)configuration against the traditional 22 mm bar spacing grid.Size selectivity analyses showed that the 17 and 15 mm grids resulted in no significant reduction in shrimp catch across all length classes.The 17 mm grid significantly reduced redfish bycatch for all length classes and the 15 mm grid significantly reduced redfish bycatch for individuals larger than 95 mm total length.Less redfish entered the codend with the experimental grids,however,the overlap in width between redfish and Northern shrimp limits the overall sorting efficiency of the grids,leaving some redfish still vulnerable to capture.

长江口鳗苗定置网多样性调查

为探明长江十年禁渔工作实施后长江口鳗苗定置网兼捕鱼类种类组成,于2023年2—4月在长江口禁捕区北界外海域(31°42′—31°43′N,122°10′—122°16′E),收集鳗苗定置网内渔获物118网次。共采集到兼捕鱼类5482尾,隶属25科47属64种。其中,海洋性鱼类26种,河口性鱼类31种,洄游性鱼类5种,淡水性鱼类2种。发育阶段包括从后弯曲期到成鱼期,其中幼鱼最多,占总兼捕鱼类尾数的52.39%,其次是稚鱼,占23.61%。相对重要性指数(IRI)分析结果表明,优势种为矛尾虾虎鱼(Chaeturichthys stigmatias)和拉氏狼牙虾虎鱼(Odontamblyopus lacepedii);重要种为刀鲚(Coilia nasus)、大银鱼(Protosalanx hyalocranius)、安氏新银鱼(Neosalanx anderssoni)、莱氏舌鳎(Cynoglossus lighti)、鲻(Mugil cephalus)、赤鼻棱鳀(Thryssa kammalensis)、陈氏新银鱼(Neosalanx tangkahkeii)、凤鲚(Coilia mystus)、棘头梅童鱼(Collichthys lucidus);以上11种鱼类占总兼捕鱼类尾数的84.77%,占总兼捕鱼类重量的87.51%。兼捕鱼类数量2月最高,4月最低,渔获物重量也呈相同趋势。渔获物中兼捕经济鱼类共47种,平均每网44.13尾。采集鳗苗1363尾,平均每采集1尾鳗苗,兼捕经济鱼类3.82尾。结果表明,鳗苗定置网对非目标兼捕鱼类以及一些经济性鱼类的早期资源存在严重损害。

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。

福建沿海鲸鲨时空分布初探及保护对策

搁浅、误捕和救助记录是研究野生动物分布和获取其基本生物学数据的重要来源,尤其是对那些缺少系统性野外调查的物种。本研究收集了福建沿海2006—2019年间鲸鲨(Rhincodon typus)的搁浅、误捕和救助记录,初步探讨福建沿海鲸鲨的时空分布情况,并提出相应的保护对策。共收集福建沿海鲸鲨搁浅、误捕和救助记录30例,包括搁浅10例、误捕18例和救助2例,其中福州鲸鲨记录大部分在平潭岛附近,这可能与平潭海域上升流带来的丰富生物资源有关;所有记录中有28例(93.3%)发生在6—10月,表明夏秋季可能是鲸鲨在福建沿海活动的高峰期。此外,有体长记录的22条鲸鲨中,17条(77.3%)为幼年个体,可能是因为幼年鲸鲨偏好在高生产力的近岸海域聚集以获取充足的食物,因此也更容易搁浅或被误捕。较多的误捕记录(60.0%)提示渔业活动对鲸鲨有较大威胁。因此,建议建立全省甚至全国性的鲸鲨搁浅误捕数据库,进一步严格和规范渔业管理,改进渔具以降低误捕鲸鲨的概率,加强对公众(特别是渔民)的宣传教育,以更好地保护这一濒危物种。

小鳁鲸的一些生物学测量数据

2004年6月山东省威海石岛的渔民偶然误捕了一头须鲸,经作者鉴定,此标本系小鳁鲸(Balaenoptera acutorostrata)。主要鉴别特征:头背面的嵴明显;左右鳍肢各有一白色的横斑;有282对白色的鲸须板。同时还对其进行了较详细的观察和测量,值得一提的是此鲸存有异常现象:有一假脐,乳沟位于生殖裂后端而非生殖裂的两旁。

欧洲地区选择性虾拖网渔具的研究进展

虾拖网渔业是世界上兼捕、抛弃问题最为严重的渔业。为了缓解虾拖网渔业的这一突出问题,世界各国、各组织的研究人员在世界各主要虾拖网渔业中开展了多样而有效的选择性研究。北大西洋北方长额虾Pandalus borealis拖网渔业、东北大西洋和地中海海螯虾Nephrops norvegicus拖网渔业是欧洲开展选择性研究最早、最全面的渔业,作者从上述2种虾拖网渔业及其兼捕、抛弃特点出发,通过对渔业中有关的尺寸选择性和种类选择性研究,特别是兼捕减少装置(BRD)的设计开发进行归纳和总结,结合渔业中有关兼捕减少技术措施的介绍,探讨了这2种渔业中选择性研究的特点及其对其他渔业选择性研究的借鉴意义,为我国今后开展虾拖网渔业选择性研究和渔业立法提供一定的参考依据。

热带海域选择性虾拖网渔具的研究进展

捕虾拖网,特别是热带海域捕虾拖网渔业的兼捕和抛弃是全球最为突出的渔业问题,而选择性渔具的开发是解决这一问题的主要技术手段。美国东南沿海和澳大利亚沿海对虾拖网渔业是典型的热带海域捕虾拖网渔业,在这些海域的捕虾拖网渔业中,大型海洋生物(海龟)和鱼类兼捕共存的特点使得选择性研究主要是以种类选择性为主,选择性装置研究也主要集中在海龟释放装置(TED)和鱼类兼捕减少装置(BRD)上。通过归纳和对比这两种渔业中所开展的选择性研究,找出选择性虾拖网研究的共性和个性,结合不同渔业中有关兼捕减少的法律法规,为中国今后开展虾拖网渔业选择性研究以及虾拖网渔业相关技术措施和法规的制定提供参考依据。

伪虎鲸的一些生物学测量数据

2003年12月山东省石岛的渔民偶然误捕了一头海豚,经作者鉴定,系伪虎鲸。主要鉴别特征全身呈暗黑色,体细长,背鳍狭长而呈镰刀形,胸鳍前缘有一特有的隆起,即所谓的“肘部”,牙齿大,呈圆锥形,上颌齿数为17,下颌齿数为20。同时,还对其进行了较详细的观察和测量。

一头罕见伪虎鲸的测量(英文)

2005年10月山东省荣成市远洋渔船的渔民偶然误捕了一头海豚,经鉴定,系伪虎鲸,且为畸形。主要鉴别特征:全身呈暗黑色,体细长,背鳍狭长而呈镰刀形,胸鳍前缘有一特有的隆起,即所谓的"肘部",牙齿大,呈圆锥形,上颌齿数为14,下颌齿数为16。同时,还对其进行了较详细的观察和测量。畸形表现在:左右口角的形状不一;左鳍肢前缘有一明显的二分叉;雌性,乳沟内无乳头,但经解剖发现腹内却有一胎儿,系雄性,体长1.8m,体重40kg。

印度洋金枪鱼渔业中鲨鱼兼捕率

鲨鱼作为金枪鱼渔业中主要兼捕种类之一,其兼捕率却较少见报。本文利用印度洋1950～2010年金枪鱼渔业生产统计数据,分析了不同作业渔具的鲨鱼兼捕率。结果表明,印度洋金枪鱼渔业中鲨鱼平均兼捕率为9.30%,其中流刺网、线钓、延绳钓、围网以及其他作业渔具兼捕率分别为22.14%、16.27%、2.59%、0.43%和56.95%,且流刺网的鲨鱼兼捕量为最高。该区域兼捕鲨鱼共计19种(包括未定种),每种作业渔具未定种的捕捞量占比最高。建议在印度洋海域有针对性地发展选择性渔具,加大鲨鱼物种鉴别和数据统计能力,综合利用兼捕物种,增加经济价值。

长吻飞旋海豚的一些生物学测量数据

2003年11月山东省石岛的渔民在黄海水域偶然误捕了一头海豚,经作者鉴定,系长吻飞旋海豚(Stenella longirostris),国家Ⅱ级重点保护动物,是黄海水域的首次记录。其主要鉴别特征:喙细长;背鳍略呈三角形;尾柄很高,具有结缔组织构成扩大的嵴;齿数:右上颌47枚,右下颌50枚,左上颌47枚,左下颌51枚。同时,还对其进行了较详细的观察和测量:此海豚系雄性,体长1.828 m。为长吻飞旋海豚的保护以及管理措施的制定提供了基本的参考资料。

库克群岛海域海洋环境因子对沙氏刺鲅兼捕率的影响

为了减少沙氏刺鲅(Acanthocybium solandri)的兼捕率,文章利用2012年9月~2012年11月在南太平洋库克群岛海域延绳钓渔业调查数据(包括钓钩深度数据,温度、盐度和叶绿素a质量浓度垂直剖面数据,作业参数和渔获统计数据),采用逐步回归的方法建立钓钩预测深度计算模型,利用统计和聚类分析的方法分析沙氏刺鲅的兼捕率与水层和温度的关系,并根据沙氏刺鲅兼捕率最高的水层推断得出其兼捕率最高的盐度和叶绿素a质量浓度范围。结果表明,库克群岛附近海域沙氏刺鲅兼捕率最高的水层和温度分别为40.0~80.0 m和26.0~28.0℃,推断得出沙氏刺鲅兼捕率最高的盐度段为36.30~36.90,叶绿素a质量浓度为0.070~0.243μg·L^(-1)。建议把钓钩深度设置到80 m以深、水温低于26℃、盐度高于36.90、叶绿素a质量浓度高于0.243μg·L^(-1)以减少延绳钓渔业中沙氏刺鲅的兼捕率。

The Development and Operational Testing of an Underwater Bait Setting System to Prevent the Mortality of Albatrosses and Petrels in Pelagic Longline Fisheries

Longline fisheries for tunas and tuna-like species present an existential threat to many populations of albatrosses and petrels worldwide. To prevent this form of mortality we developed a new technology designed to deploy baited hooks underwater beyond the dive depths of?seabirds (6 - 10 m for the species most commonly caught). The underwater bait setter is a stern-mounted, hydraulically-operated and computer-controlled?device that catapults?baited hooks underwater in a steel capsule?connected to hydraulic winches by Spectra&reg;rope. Baits are flushed from the capsule by water pressure through a spring-loaded bait release door. The chief engineering challenges in the developmental stageswere ensuring:?1) bait delivery?to target depths with cycle times (time from release to recovery) that were practical for fishing operations;?2) bait retention in the capsule (no drop-outs) on the descent phase of the cycle;?3) baits, upon?release at target depth, were not drawn up the water column on the capsule recovery phase (from possible hook-ups and/or suction);and?4) the retention of baits?on?hooks post-release from the capsule was not affected by the mechanical release underwater. Operational trials with the final version of the capsule yielded?satisfactory cycle times to depths of 6 - 10 m. All baits were retained?in the capsule on the descent and?released as required?at target depths (n = 606 deployments). Bait retention on hooks post release from the capsule and retention on hooks hand-set at the surface (the conventional method) were statistically indistinguishable.?The underwater bait setter is modular in construction and can be fitted to all types of vessel sterns.

中西太平洋金枪鱼延绳钓主要渔获物垂直结构的初步研究

根据2012年7~11月金枪鱼科学观察员在中西太平洋采集的钩位深度以及渔获物的钓获钩位数据,分析了各钩位的上浮率和钓获鱼种的垂直分布结构,并比较了不同鱼种垂直分布的差异性。结果表明：（1）钓钩绝对上浮率变化范围为0.49~44.73 m,相对上浮率的变化范围为0.65%~16.69%,平均绝对上浮率为23.29 m,平均相对上浮率为8.87%。（2）12种主要渔获钓获深度范围差异很大,大魣（Lampris guttatus）的平均钓获深度最浅,为75.92 m,蓝枪鱼（Makaira nigricans）的平均钓获深度最深,为228.19 m。聚类分析显示12种主要渔获物可以分成3种垂直分布结构。（3）11种主要兼捕渔获钓获深度均与长鳍金枪鱼（Thunnus alalunga）钓获深度呈显著性差异。

Additional Records of the American Elephantfish <i>Callorhinchus callorynchus</i>(Chondrichthyes, Holocephali, Chimaeriformes) in Southeastern Brazil

Chimaeras, fish in the order Chimaeriformes, are among the rarest and least studied fish in the class Chondrichthyes (cartilaginous fish). Previous records have indicated that a species of chimaera known as the elephantfish, or cockfish, Callorhinchus callorynchus, may be found in marine waters off southeastern Brazil, as far north as the state of São Paulo. Here we report that C. callorynchus, caught with bottom gillnet, was found in an urban fish market in the city of Rio de Janeiro (~23˚S). This and other records from a variety of places call into question the distribution limits of the American elephantfish in the southwestern Atlantic Ocean and whether, at least seasonally, this species may often be found as far north as the state of Rio de Janeiro. Because of scientific and conservation interests in the poorly known Chimaeriformes, we recommend long-term monitoring of the fish catch in ports along the southern Brazilian coast, to better understand the natural history of the intriguing chimeras.

热带西太平洋帆蜥鱼胃含物组成分析

根据中国金枪鱼延绳钓渔业观察员于2017年9月至2018年1月在热带西太平洋(165°45′E～178°00′W,03°02′S～18°34′S)采集的138尾帆蜥鱼(Alepisaurus ferox)样本,对其胃含物组成进行了研究。结果显示,帆蜥鱼胃含物中共鉴定出61种(类)生物,分属鱼类、软体动物、甲壳类、多毛类、刺胞动物和海樽类等6大类44科。此外,还观察到了同类相食现象以及塑料垃圾。胃含物的Shannon-Wiener多样性指数(H')为2.71,Pielou均匀度指数(J')为0.67,饵料优势指数(D)为0.12。相对重要性指数(IRI)分析结果显示软体动物为帆蜥鱼的主要食物,其IRI为7 573.31,占IRI总和百分比(IRI%)为53.11%。在科一级水平上,褶胸鱼科、帆蜥鱼科、龙骨螺科、翼管螺科、单盘蛸科、爪乌贼科、刺虾科、宽腿鰯科、Eurytheneidae和浮沙蚕科为其优势饵料。

张网渔具霞水母兼捕减少装置的初步研究

近年来,霞水母的旺发严重影响了东、黄海秋冬汛张网渔业。为了维持渔业生产的正常进行,利用霞水母和目标渔获物的个体大小以及行为特性的差异,通过在网囊前安装网目长度为45cm的分隔网片和释放口所组成的兼捕减少装置(BRD)来释放霞水母。根据2000年和2001年的海上试验显示,该装置能有效减少霞水母兼捕,平均释放率达91.29%;而目标种类的平均逃逸率为13.35%,其中梭子蟹、鲳鱼的逃逸率较高,分别为52.84%和33.44%,带鱼和小黄鱼的逃逸率较低,分别为5.23%和6.27%,棘头梅童鱼的逃逸率为9.14%;同时由于霞水母的释放,使得作业中的暴网事故明显减少;霞水母BRD自设计开发、试验以后,得到了广泛的运用,自2003年起,已在江苏省启东市所辖350余艘张网渔船上全面推广应用。