鲨鱼鳞片的研究

本文观察分析了9目21科62属189种鲨鱼的盾鳞，其中采自国内的有80种，参考国外文献和图的有109种。依照盾鳞的棘部尖突和纵嵴的数目及其基板的形态，可分为16个式型，它们的形态特征同分类及生活习性有一定的关系。     

淡水鲨鱼养殖技术

芒淡水鲨鱼是白苏氏园腹的俗称，隶属硬骨鱼纲，鲶形目，科，属。主要分布于东南亚一带，是泰国、马来西亚等地的优良淡水养殖鱼类。有黑、白二种体色，黑色的俗称淡水蓝鲨，原产泰国，１９７８年引进我国；白色的俗称淡水白鲨、原产马来西亚，１９９８年引进我国。海南省农业学校于２００１年６月在本校养殖实验基地引进１５００尾白鲨，１５００尾蓝鲨进行小面积养殖试验，取得较好成效，现将养殖试验结果报告如下。１生物学特性１．１外部形态淡水鲨鱼体表光滑无鳞，体形长而侧扁，脊部隆起，头部扁平呈圆锥形，吻短，口亚下位，前后鼻孔…     

淡水鲨的养殖

淡水鲨学名为苏氏园腹鱼芒(Ｐａｎｇａｓｉｕｓｓｕｔｈｉ),俗称虎头鲨,八丁鱼,或八珍鱼。隶属于鲶形目、鱼芒科、圆腹鱼芒属。主要分布于东南亚一带,其肉味鲜美可口,无肌间刺,是泰国、马来西亚等地的优良淡水养殖鱼类。1　生物学特征1 1　形态特征:淡水鲨体长形,体色有黑、白、灰、红四种,腹圆,没有腹棱,头部圆锥形,吻短,口亚下位,口须2对,具有一脂鳍,体表光滑无鳞。红鲨鱼即水晶巴丁鱼,多做观赏鱼饲养。1 2　生活习性:淡水鲨属于热带鱼类。在自然条件下喜栖息于水体的中下层,抗低溶氧能力较强,在污水中能长期栖息和生存。抗病能力和适…     

淡水鲨鱼人工繁殖试验总结

淡水鲨鱼学名为苏氏圆腹鲑[Pangasius、sutchi Fowler]。隶属鲇形目，（鱼芒）鲇科、（鱼芒）鲇属，主要分布于东南亚一带，是泰国、马来西亚等地的优良淡水养殖鱼类。目前我国引进的品种有体色红白相间和蓝白相间两种，所以又称红鲨和蓝鲨。该鱼体表光滑无鳞、体型长而侧扁，具脂鳍，为热带鱼类。适温范围为13～36％，生长适宜水温22～36℃，对低温的耐受能力较弱，下限水温为12℃。由于其具有食性杂、     

苏氏圆腹(鱼亡)高产养殖技术

苏氏圆腹[Pangasius sutchi(Fowier)],又称淡水鲨鱼,隶属于科,属,主要分布于东南亚一带,是泰国、马来西亚等地的优良淡水养殖鱼类,目前我们引进的品种有体色红白相间和蓝白相间两种,所以又称红鲨和蓝鲨.该鱼体表光滑无鳞,体形长而侧扁,具脂鳍.苏氏圆腹为热带性鱼类,水温下限为12℃.由于具有食性杂,生长快、耐低氧、病害少,适应性强等养殖优点,加之其肌间刺少,肉质细嫩鲜美,营养价值高,因而具有广泛的推广养殖价值.     

名优新品种 淡水鲨鱼

<正>淡水鲨鱼属圆腹属,是苏氏圆腹的俗称,因体型似鲨而被称为"淡水鲨鱼",其实和鲨鱼并无亲缘关系。又称虎头鲨、巴丁鱼或八珍鱼,主要分布在东南亚一带,有黑、白、灰三种体色,分河系与海系生长。黑色的称淡水黑鲨,原产于泰国,1978年引进我国;白色的称淡水白鲨,原产于马来西亚,1998年引入我国;灰色的称马来亚河系灰鲨,肉质较好,2000年引进我国。形态特征鱼体呈纺锤型,形长而侧扁背鳍     

台湾海峡鲨鱼类资源及其利用问题

鲨鱼类系侧孔类的软骨鱼类,经济价值很高,肉可食用,皮可制革,鳍条制成的“鱼翅”是名贵海珍品。鲨鱼类还是药效很高的海洋生物。世界上鲨鱼种类约为250种,其中会吃人的鲨鱼有:猫仔鲨、哈仔鲨、剑鲨、白边真鲨、大青鲨等10多种。我国的鲨鱼约有80种,按群体可分为四个群,第一个群     

鲨鱼伤人的奥秘

鲨鱼号称“海中狼“,它那贪婪凶残的本性给人们留下了可怕的印象.因而往往有“谈鲨色变“. 　　世界上有300多种鲨鱼,吃人的鲨鱼大约有20多种,其中有噬人鲨、灰鲨、双鬓鲨、虎鲨等,要是在海滨游泳或落水者若遇到这类鲨鱼,是很危险的,可谓凶多吉少.近两年来在香港和深圳海域都有发生鲨鱼伤人的事件,所以千万不可掉以轻心.……     

苏氏圆腹高产养殖技术

苏氏圆腹鱼芒 [Ｐａｎｇａｓｉｕｓｓｕｔｃｈｉ (Ｆｏｗｉｅｒ) ],又称淡水鲨鱼 ,隶属于鱼芒科 ,鱼芒属 ,主要分布于东南亚一带 ,是泰国、马来西亚等地的优良淡水养殖鱼类 ,目前我们引进的品种有体色红白相间和蓝白相间两种 ,所以又称红鲨和蓝鲨。该鱼体表光滑无鳞 ,体形长而侧扁 ,具脂鳍。苏氏圆腹鱼芒为热带性鱼类 ,水温下限为 12℃。由于具有食性杂 ,生长快、耐低氧、病害少 ,适应性强等养殖优点 ,加之其肌间刺少 ,肉质细嫩鲜美 ,营养价值高 ,因而具有广泛的推广养殖价值。为了探讨苏氏圆腹鱼芒的高产养殖技术 ,我们于 1999年进行了小面…     

南沙群岛西南部和北部湾口海域鲨鱼的种类组成和数量分布

依据2012~2013年在南沙群岛西南部和北部湾口海域进行的拖网调查数据,分析了调查海域中鲨鱼的种类组成和数量分布。结果表明,本次调查共兼捕到鲨鱼16种,分别隶属于5目10科。其中,2012年秋季航次出现鲨鱼6种,北部湾口海域以阴影绒毛鲨(Cephaloscyllium isabellum)和网纹绒毛鲨(C.fasciatum)为优势种,南沙群岛西南部海域以阴影绒毛鲨和短吻角鲨(Squalus brevirostris)为优势种;2013年春季航次出现鲨鱼13种,北部湾口海域以阴影绒毛鲨为绝对优势种,南沙群岛西南部海域以哈氏原鲨(Proseyllium habereri)和阴影绒毛鲨为优势种。鲨鱼的尾数单位捕捞努力量渔获量(CPUEN)范围为1~27 ind·h~(-1),重量单位捕捞努力量渔获量(CPUEW)范围为0.19~5.85 kg·h~(-1),在整个调查海域范围内,南沙群岛西南部海域为鲨鱼主要分布。本文调查分析结果可为掌握南海鲨鱼的种类组成和地理分布现状以及估算鲨鱼资源量提供基础资料,也可为制定鲨鱼养护等政策提供科学依据。     

The effects of climate variability on zooplankton and basking shark (Cetorhinus maximus) relative abundance off southwest Britain

At small spatial scales basking sharks (Cetorhinus maximus) forage selectively on zooplankton along thermal fronts, but the factors influencing broader scale patterns in their abundance and distribution remain largely unknown. Using long‐term sightings data collected off southwest Britain between 1988 and 2001, we show that the number of basking sharks recorded was highly correlated with abiotic factors, principally sea surface temperature (SST) and the lagged effect of SST in the previous month, but only very weakly to zooplankton density. This suggests that the changes in number of basking sharks recorded over large spatio‐temporal scales are more closely related to the availability of climate‐driven thermal resources than prey availability, whereas the converse is supported by previous studies at local scales. Taken together, these results imply scale‐dependent behavioural responses in basking sharks, with small‐scale foraging movements linked by broad scale responses to temperature variation.     

Melanomacrophages in three species of free-ranging sharks from the northwestern Atlantic, the blue shark Prionacae glauca (L.), the shortfin mako, Isurus oxyrhinchus Rafinesque, and the thresher, Alopias vulpinus (Bonnaterre)

The melanomacrophage aggregates or cells (MMC) are commonly used as biomarkers of exposure to pollution in fish, albeit their numbers and morphological characteristics can be influenced not only by environmental toxins but also by a range of physiological parameters and pathological conditions. Accordingly, before we can use MMC as biomarkers in any fish species, their normal, 'background' characteristics have to be established in apparently healthy fish. The knowledge of MMC in sharks is minimal. The aim of this study was to characterize MMC from 51 free-ranging, large pelagic sharks from the northwestern Atlantic, including shortfin mako, Isurus oxyrhinchus , thresher, Alopias vulpinus and blue shark, Prionacae glauca . The rationale of this study was twofold. First, because, sharks have life histories predisposing them to the accumulation of environmental toxins they constitute good sentinel species of the health of the global marine ecosystem. Second, because many shark populations are in decline or threatened by extinction, we need to expand our understanding of their health status in order to develop appropriate protective measures. All sharks were collected by sports fishing gear between June and August in 2007. Their health condition was assessed by necropsy, morphometrics, and by microscopic examination of gonads, livers, spleens and kidneys. Routine, haematoxylin and eosin and/or Pearl's reagent-stained paraffin embedded sections were studied by light microscopy. Our results provide the first data on the morphometric and morphological characteristics of MMC in viscera of apparently healthy free-ranging sharks from the northwestern Atlantic.     

Serum steroid concentrations and development of reproductive organs during puberty in male bonnethead sharks, Sphyrna tiburo

Puberty is a critical, hormone-mediated event during which an animal acquires the ability to breed and propagate. Despite the importance of this stage in animal reproduction, little is known regarding the physiological factors that regulate and/or accompany puberty in several vertebrate groups including elasmobranchs. To address the need for such information, the present study investigated morphological and hormonal changes that occur during puberty in male bonnethead sharks (Sphyrna tiburo). Serial changes in development of claspers, paired copulatory organs in male elasmobranchs, and serum steroid concentrations during puberty were evaluated in captive-held male S. tiburo. Captive-animal studies were supplemented by observations on gonadal development, gonaduct morphology, and serum steroid concentrations in feral, peripubertal male S. tiburo. Changes in size and histological architecture of testes and gonaducts of peripubertal sharks mirrored the seasonal progression of events that occur in these structures in mature males. Claspers grew in length continuously during puberty, but sharks did not reach functional maturity until a short period before mating activity commences in the mature population. Clasper growth appeared to be strictly regulated in S. tiburo, perhaps to ensure growth of these organs to sizes deemed critical for reproductive success. Serum concentrations of testosterone, dihydrotestosterone, progesterone, and 17β-estradiol increased in both captive and feral sharks during pubertal development, and may be associated with development of the gonads and gonaducts. Differences in hormone profiles of captive and feral sharks were observed at certain periods during puberty, but their origin remains unclear. This revised version was published online in July 2006 with corrections to the Cover Date.     

Can drifting objects drive the movements of a vulnerable pelagic shark?

1. Juvenile silky sharks (Carcharhinus falciformis) regularly associate with floating objects yet the reasons driving this behaviour remain uncertain. Understanding the proportion of time that silky sharks spend associated with floating objects is essential for assessing the impacts of the extensive use of fish aggregating devices (FADs) in the tropical tuna purse-seine fisheries, including increased probability of incidental capture and the potential of an ecological trap.
2. Previous studies provided insight into the amount of time that silky sharks spent at an individual FAD but were unable to assess neither the time spent between two associations nor the proportion of time spent associated/unassociated.
3. The percentage of time that juvenile silky sharks spend unassociated with floating objects was estimated through the analysis of horizontal movements of 26 silky sharks monitored with pop-up archival tags. Under the assumption that a high association rate with drifting FADs would align the trajectories of tracked sharks with ocean surface currents, a novel methodology is proposed, based on the comparison of shark trajectories with simulated trajectories of passively drifting particles derived using a Lagrangian model.
4. Results revealed that silky shark trajectories were divergent from surface currents, and thus unassociated with FADs, for at least 30% of their time. The potential of the methodology and the results are discussed in the context of increasing FAD densities in the Indian Ocean.

     

Distribution,body length,and abundance of blue shark and shortfin mako offshore of northeastern Japan,as determined from observed pelagic longline data, 2000–2014

Longline surveys have been conducted in the Northwest Pacific Ocean from 2000 to 2014 using chartered commercial longline vessels. Each year, two cruises were conducted offshore of northeastern Japan from mid‐April to mid‐June. For each longline set during the surveys, onboard scientists collected detailed biological information about the species caught, such as the size and sex, and recorded the catch numbers for all species. Blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus) have eurythermal distributions, but the application of a generalized additive model (GAM) showed that the sea surface temperatures (SSTs) at catch sites positive for shortfin mako were warmer than those for blue shark. On the basis of the GAM, the probabilities of occurrence of both sharks differed by size category: small sharks had a narrower SST range than that of large sharks. Most catches of both sharks were juveniles, and the nominal catch rate of blue shark was more than 10 times that of shortfin mako. The standardized catch per unit effort (CPUE) for both species was calculated using a generalized linear model (GLM) with negative binomial errors, or a delta‐lognormal GLM. The standardized CPUE for blue shark in the second quarter of the year peaked in the mid‐2000s and then decreased, but it has been increasing since 2012. The CPUE for shortfin mako in the second quarter generally increased, with fluctuations.     

Congruent trends in long-term zooplankton decline in the north-east Atlantic and basking shark (Cetorhinus maximus) fishery catches off west Ireland

Trends in basking shark ( Cetorhinus maximus ) fishery catches off Achill Island, west Ireland between 1949 and 1975 were examined in relation to zooplankton (total copepod) abundance in four adjacent sea areas over a 27-year period. The numbers of basking sharks caught and copepod abundance showed downward trends and were positively correlated ( r -value range, 0.44–0.74). A possible explanation for the downward trend in shark catches was that progressively fewer basking sharks occurred there between 1956 and 1975 because fewer copepods, their food resource, occurred near the surface off west Ireland over the same period. We suggest that the decline in basking sharks may have been due to a distributional shift of sharks to more productive areas, rather than a highly philopatric, localized stock that was over-exploited.     

丝足鲈的形态特征与核型

丝足鲈(Osphronemus goramy),英文名为Giantgouramy,分类上隶属鲈形目(Perciformes),长丝鲈科(Osphronemidae),原产于东南亚诸国,为东南亚的养殖对象。1998年,我所从越南引进该种鱼,见图1。由于其生长快,食性杂,易饲养,在国内已逐渐成为一个新的养殖对象。其体型奇特,尾鳍鲜红,有一定的观赏价值。因该种鱼引进我国时间不长,有关的研究很少。为了推广养殖该种鱼,有必要全面了解该鱼的形态特征以及其核型。因此本文对于丝足鲈的形态特征及核型进行了详细观察及研究。     

Blood pressure and heart rate during tonic immobility in the black tipped reef shark,Carcharhinus melanoptera

Tonic immobility was induced in black tipped reef sharks (Carcharhinus melanoptera) and heart rate and ventral aortic blood pressure recorded. Without branchial irrigation, tonic immobility was correlated with a significant depression in blood pressure and heart rate irrespective of the sharks being in air or in water. Tonic immobility with branchial irrigation resulted in a significant increase in blood pressure in sharks in air, but not in water. Heart rate was unchanged when the gills were irrigated. Intra-arterial injections of atropine abolished the bradycardia and blood pressure rise associated with tonic immobility. We conclude that, during tonic immobility, sharks are able to receive afferent information from the ventilatory system and make appropriate responses via the vagus nerve.     

Broad‐scale movements and pelagic habitat of the dusky shark Carcharhinus obscurus off Southern Australia determined using pop‐up satellite archival tags

We investigated the broad‐scale movements and pelagic habitats of large juvenile dusky sharks (Carcharhinus obscurus) off Southern Australia. Pop‐up satellite archival tags (PSATs) were deployed on three large juvenile dusky sharks (～2.2–2.6 m total length) for 6 months in Spencer Gulf during 2010. Tagged dusky sharks all migrated westward and across the Great Australian Bight (GAB) during autumn to offshore shelf waters off Western Australia. Estimated minimum distances travelled ranged from 1760 to 2736 km. Depths occupied by tagged dusky sharks ranged from the surface to 355 m. The most common thermal ranges occupied were 19–22°C. Broad‐scale movements of large juvenile dusky sharks across the continental shelves combined with periods of residency in semi‐protected gulf waters indicated that a multi‐jurisdictional management approach may be appropriate for this species.