日本鳗鲡人工育苗的进展及存在问题

鳗鲡属隶属于硬骨鱼纲（Ｏｓｔｅｉｃｈｙｅｓ）、鳗鲡目（Ａｎｇｕｉｌｌｉｆｏｒｍｅｓ）、鳗鲡科（Ａｎｇｕｉｌｌｉｄａｅ）。鳗鲡目鱼类大多数生于海洋,但鳗鲡科鱼类大部分属降河繁殖洄游鱼类,它们在海洋中产卵繁殖,幼鳗孵化后漂游到沿岸,然后进入淡水河流中成长。鳗鲡属共有１７种,广泛分布在世界各地,其中有１２种是属热带和亚热带种类。一、人工繁殖鳗鲡的研究早在３０年代人们就开始鳗鲡人工催熟的试验。１９７３年春日本北海道大学山本教授等首次获得受精卵。同年年底和次年初孵出了第一批人工繁殖的仔鳗,仔鳗存活了１２０小时,我…     

鱼类仔鱼期的摄食和生长

鱼类仔鱼期的摄食和生长殷名称（上海水产大学，２０００９０）关键词鱼类，仔鱼期，摄食，生长ＦＥＥＤＩＮＧＡＮＤＧＲＯＷＴＨＯＦＴＨＥＬＡＲＶＡＳＴＡＧＥ．ＯＦＦＩＳＨ￥ＹｉｎＭｉｎｇｃｈｅｎｇ（ＳｈａｎｇｈａｉＦｉｓｈｅｒｉｅｓＵｎｉｖｅｒｓｉｔｙ，２...     

鳗鲡人工饲养技术

鳗鲡人工饲养技术郑建平（广东省肇庆市粮食局科技中心）日本鳗鲡（ＡｎｇｕｉｌｌａＪａｐｏｎｉｃａ）属鳗鲡目、鳗鲡科、鳗鲡属，为名贵鱼类。１９９３年我们在广东肇庆市进行了日本鳗鲡（以下简称鳗鲡）的养殖试验。以后又在广东新兴县推广鳗鲡的养殖，效益良好。现将...     

日本鳗鲡人工育苗及仔鱼饲料研究

日本通过40年对鳗鲡成熟控制技术的研究,特别是近几年来采用17,20β-dihydroxy-4-pregnen-3-one(DHP)的鳗鲡雌鱼成熟诱导技术,使高质量鳗鲡受精卵的取得具有相当高的把握性。日本水产厅养殖研究所采用以鲨鱼卵冷冻干燥粉末为主要成份并含有磷虾或其它鲜鱼虾抽提液的糊状饲料,喂食人工孵化的日本鳗鲡仔鱼取得举世嘱目的突破性进展,但柳叶状仔鱼全长达到30mm以后几乎不再摄食,出现生长停滞,并已变得十分衰弱。全面攻克日本鳗鲡人工育苗难题尚待时日,特别是研制能有效促进后期柳叶状仔鱼生长并变态的全价育苗饲料已成为目前关注的焦点。     

水产资源

941962 亚马逊河中游鱼类的卵大小和仔鱼发育=Egg size and larval development incentral anazonian fish[刊,英]/Araujo-LimaC A R M//J.Fish Bio1..—1994.44(3).—371～389作者研究了亚马逊河中游鱼类14种(脂鲤目7种、丽鱼科5种和鲇目2种)的仔鱼发育和卵大小的关系。在激活时作为卵黄干重测定卵的大小(卵减去卵壳)。在发育阶段作为仔鱼干重和年龄(从激活小时)洲定仔鱼发     

长江口沿岸碎波带三种暖水性鱼类仔鱼的出现

2006年6~10月,按月在长江口沿岸碎波带设置的13个采样点,用小型拖网进行仔稚鱼多样性调查时,采集到遮目鱼仔鱼1 ind、海鲢仔鱼40 ind、大海鲢仔鱼144 ind,这是在长江口水域首次发现遮目鱼仔鱼和海鲢的仔鱼。本文详细描述了该三种暖水性鱼类仔鱼的形态特征,探讨了其水平分布与环境因子的关系,提出了长江口附近水域存在产卵场的可能性,为该三种暖水性鱼类早期生活史中的地理分布以及生态习性提供科学依据。     

日本鳗鲡的人工养殖技术

日本鳗鲡的人工养殖技术郑建平广东省肇庆市粮食局粮油科技发展中心美国青蛙养殖场日本鳗鲡（Ａｎｇｕｉｌｌａｊａｐｏｎｉｃａ）属脊索动物门、脊椎动物亚门、鱼纲、鳗鲡目、鳗鲡科、鳗鲡属。日本鳗鲡（以下简称鳗鲡）肉质细嫩鲜美，内含多种维生素、蛋白质及易被人体消...     

日本鳗鲡的生物学特征及人工饲养技术（一）

日本鳗鲡的生物学特征及人工饲养技术（一）日本鳗鲡（Ａｎｇｕｉｌｌａｊａｐｏｎｉｃａ）属脊索动物门、脊椎动物亚门、鱼纲、鳗鲡目、鳗鲡科、鳗鲡属。日本鳗鲡（以下简称鳗鲡）肉质细嫩鲜美，内含多种维生素、蛋白质及易被人体消化吸收的多烯不饱和脂肪酸，是一种风味...     

鳗鲡种质资源的研究进展

鳗鲡是鳗鲡属鱼类的统称,在分类学上隶属于硬骨鱼纲、鳗鲡目、鳗鲡科、鳗鲡属,广泛分布于全球热带、亚热带和温带地区[1-2]。鳗鲡为洄游性鱼类,具有特殊的生活史,一般在淡水中生活、海水中产卵孵化[3]。鳗鲡味道鲜美、营养丰富、肉多刺少、经济价值高,是世界性重要经济鱼类之一     

人工诱导池塘养殖鳗鲡成熟产卵以及胚胎和仔鱼发育

降海鳗鲡一直是作为研究鳗鲡人工繁殖的材料,由于降海鳗鲡的资源衰退,选用池塘养殖鳗鲡作为亲本的研究成为热点。尽管人工诱导野生降海鳗鲡获得的胚胎发育过程的研究已报道,但人工诱导池塘养殖鳗鲡的胚胎及仔鱼早期发育未见报道。本文应用池塘养殖日本鳗鲡取代野生降海日本鳗鲡进行人工繁殖,2002年的孵化批次共80次,其中大部分为人工授精卵(60次),一部分(20次)为自然产卵。受精率为(44.03±21.99)%,孵化率为(65.76±19.48)%,共计获得苗种349.9万尾。连续记录了鳗鲡的胚胎和早期仔鱼的发育过程。在水温为20.5℃时,胚胎发育需要时间为49h,所需积温1005℃.h;在水温为22.5℃时,胚胎发育需要时间为39h,所需积温878℃.h;在水温为24.5℃时,胚胎发育需要时间为34h,所需积温833℃.h。     

Hen egg yolk and skinned krill as possible foods for rearing leptocephalus larvae of Anguilla japonica Temminck & Schlegel

Usual diets for rearing leptocephalus larvae of Japanese eel Anguilla japonica include eggs of the endangered spiny dogfish Squalus acanthias (SE). We investigated the effects of alternative food materials, hen egg yolk (HEY) and exoskeleton‐free (skinned) Antarctic krill (SAK), on the growth and survival of eel larvae. We found that feed comprising whole krill including exoskeleton (WAK) containing higher levels of fluoride (37.89 mg kg^?1) was acutely toxic to eel larvae exposed to this alone. In contrast, extract from SAK containing lower concentrations of fluoride (4.25 mg kg^?1) showed no apparent adverse effects. Growth of larvae fed a mixture of SE and SAK in a feed trial of 58 days [mean body weight (BW), 6.0 mg] was about twofold higher than that of larvae fed a mixture of SE and WAK (3.2 mg) (P < 0.01). A mixture of HEY and SAK also had some dietary benefits for eel larvae, enabling them to survive for up to 58 days and to grow significantly (mean BW, 2.4 mg), compared with their initial weight (mean BW, 0.2 mg) (P < 0.001). Although additional nutritional improvements are needed, the present results suggest that combination diet HEY and SAK may be a good alternative to SE as an effective diet for eel larvae.     

Developmental changes in pituitary–thyroid axis, and formation of gonads in leptocephali and glass eels of Anguilla spp.

SUMMARY: Pituitary, thyroid gland and gonads in leptocephali of Japanese eel Anguilla japonica (19.8–32.6 mm in total length), A. obscura (45.0 mm), and A. bicolor pacifica (49.5 mm) and those in glass eels of the Japanese eel were histologically and immunohistochemically examined in order to observe the developmental changes of these endocrine organs in the Anguillidae. The pituitary, consisting of adenohypophysis and neurohypophysis in Japanese eel leptocephali over 22.5 mm, did not contain thyroid stimulating hormone (TSH) immunoreactive cells. Such cells were, however, detectable in the more developed pituitaries of leptocephali of A. obscura and A. bicolor pacifica and in those of glass eels. Conversely, thyroxine (T₄)-immunoreactive thyroid follicles could be detected in all specimens, both leptocephalic and glass eel. Only in glass eels, gonads were found in the body cavity, and these gonads harbored one or two primordial germ cells (PGC) per cross-section. Our results indicate that thyroid hormones (TH) production started prior to TSH production, and that TSH and TH are both secreted during the metamorphosis from leptocephalus to glass eel. Therefore, it is plausible that the TSH–TH axis is involved in the metamorphosis from leptocephalus to glass eel, but not in the early growth from preleptocephalus to leptocephalus.     

Larval abundance across the European eel spawning area: An analysis of recent and historic data

The abundance and distribution of leptocephalus larvae of the European eel (Anguilla anguilla, Anguillidae) were examined using ten historic and recent Sargasso Sea expeditions that were selected on the basis of having the largest number of sampling stations and highest catches. The surveys cover the period 1920–2014. Station data were recalculated to the same unit of larval density per unit area, and the irregular station positions were transformed to a regular spatial grid to allow calculation of comparable measures of abundance of the youngest (0+) leptocephalus cohort. The result is that the mean and maximum densities of 0+ leptocephali after 2007 on average have decreased by 70%–80% from the densities during the period before the drastic decrease in glass eel recruitment, which started in the 1980s. This is of the same magnitude as the change in spawning stock, if the total continental commercial landings are used as a proxy. In the same period, the glass eel recruitment in Europe has decreased by more than 95%. The conclusion is that a major cause for the recruitment decrease may be an increased leptocephalus mortality during the oceanic phase or a large geographic shift in glass eel arrival. Combining the survey data, the spatial distribution of 0+ leptocephali was concentrated south of the northernmost front in the Subtropical Convergence Zone, but high densities were also found far south of the front in the western part of the distribution area and leptocephali were present also north of the average frontal position.     

日本鳗鲡仔鱼的开口饵料和行为特征

在连续多年日本鳗鲡人工繁殖实验的基础上,研究了不同饵料对日本鳗鲡仔鱼存活率的影响,并记录了仔鱼的运动特征和摄食行为。结果显示,与对照组(不投饵)相比,投喂以鲨鱼卵、磷虾提取液为基础的饵料和以鲨鱼卵、海蜇匀浆液为基础的饵料以及微绿球藻液均提高了日本鳗鲡仔鱼的存活率,仔鱼发育至柳叶鳗前期阶段;而投喂以鲨鱼卵、卤虫匀浆液为基础的饵料和以卤虫匀浆液、磷虾提取液为基础的饵料,以及轮虫、海带+龙须菜匀浆液或海蜇以及发酵鲨鱼肉,均降低日本鳗鲡仔鱼的存活率。实验同时还研究了日本鳗鲡仔鱼的主动摄食行为,摄食时仔鱼先用吻端反复多次触碰食物,然后张开下颌咬食,证实了日本鳗鲡早期仔鱼的摄食方式是触碰后咬食。     

Expression of pancreatic enzyme genes during the early larval stage of Japanese eel Anguilla japonica

ABSTRACT: To reveal the ontogeny of pancreatic exocrine function in the early larval stage of eel, cDNAs encoding major pancreatic enzymes, trypsinogen, amylase and lipase were identified from the Japanese eel Anguilla japonica and their expression pattern in larvae was analyzed. The cloned eel trypsinogen precursor consisted of 224 amino acids and showed 82.2% identity to trypsinogen-2 of winter flounder Pleuronectes americanus . The eel amylase precursor consisted of 512 amino acids and showed 77% identity to winter flounder amylase. Eel pancreatic lipase was composed of 470 amino acids and had 58.3% of identity to human pancreatic lipase. In the eel larvae, mRNA expression of trypsinogen and amylase was first detected at 6 days post-hatching (d.p.h.), and the expression level increased between 7 and 8 d.p.h. In contrast, mRNA expression of lipase was first detected at 8 d.p.h. Eel larvae start to feed actively at 8 d.p.h. Thus, it was indicated that eel pancreas starts to synthesize digestive enzymes at 6 d.p.h. and acquires full function by the onset of exogenous feeding at 8 d.p.h.     

Digestion of larval American shad by cyprinids

Cyprinids have pharyngeal teeth for grinding food before swallowing and a continuous gut with no discrete stomach. This digestive tract structure, as well as the feeding behavior traits shown by cyprinids, makes it difficult to identify and measure the amount of food consumed by these fishes. The relations among quantity of food in cyprinid gut, time after feeding and predator size were described by log-linear multiple regression. The number of intact American shad (Alosa sapidissima (Wilson)) larvae eaten in laboratory experiments was estimated by extrapolating the regression for the amount of food in the gut over time for predators of various size. The numbers of larval American shad in guts of fish captured in the Juniata River, Pennsylvania, were not significantly different from those estimated with the equations derived from laboratory data. In view of their abundance in rivers and their potential digestion rate for larval fish, cyprinids can be expected to have a marked influence on reducing the numbers of larval American shad.     

Isolation and characterization of bacteria causing mortality in early stage larvae of captive‐bred Japanese eels (Anguilla japonica Temminck & Schlegel)

Bacteria with lethal effect on eel larvae were isolated from moribund captive‐bred eel larvae and their 16S rRNA gene sequences were analysed. Nucleotide sequence of 10 isolates showed highest similarity with Lacinutrix algicola, Crocinitomix catalasitica and Pseudoalteromonas rubra. Age‐dependent changes in the susceptibility of eel larvae were observed in response to challenge by a highly lethal isolate. Compared with 10 and 11 days after hatching (DAH), larval susceptibility to the highly lethal isolate was lower at 18 DAH. We found that the bacterial isolates have lethal effect on the captive‐bred eel larvae, especially at the early developmental stage. These results will be useful to establish appropriate culture practices for eel larvae that will improve the success of mass production of glass eels for aquaculture.     

Decreasing dietary lipids improves larval survival and growth of Japanese eel Anguilla japonica

Shark eggs-based diet is the only diet by which eel larvae can grow to glass eels in captivity. However, the high level of lipids in the diet is suggested to negatively affect eel larvae. This paper examines the effect of defatted shark eggs (DSE) and hen egg yolk (HY) on growth and survival of larvae of Japanese eel Anguilla japonica. Lyophilized shark egg and commercial HY were defatted with n-hexane, and four experimental diets were prepared using both defatted and untreated shark eggs and HY. Larvae were reared for 3 weeks by feeding the experimental diets. The highest survival rate was observed in the larvae fed DSE, and larvae fed HY showed the lowest survival rate. The best growth was found in larvae fed DSE, followed by shark eggs and defatted HY, and the worst growth was in HY-fed larvae. These results show that decreasing dietary lipids improves the nutritional value of both shark eggs and HY for eel larvae. Regulation of the dietary lipid level may positively affect the larval performance of eels by combination of ingredients with a low lipid content.     

荻芦溪日本鳗鲡的食性研究

本试验于1987年每月或隔月从福建莆田获芦溪采集日本鳗鲡(Anguilla japonica)共256尾进行该种的食性研究。结果显示鳗鲡为典型的肉食性鱼类。其主要食物为蟹类、虾类和鱼类,次要食物为摇蚊科、蜉蝣目和蜻蜓目等的幼虫。鳗鲡的摄食强度随体长增长而增强,在6—7月份最强,年平均空肠率为24.8%。鳗鲡的食物组成随季节不同和个体大小而有所差异。