山女鳟低温养殖生产性能观测试验

在年均水温8℃的高寒地区进行了生产性山女鳟养殖试验。发眼卵至12、22月龄鱼育成率分别为70.7%和56.4%,平均体重分别为41.58 g和213.0 g,单产分别为9.2 kg/m~2和18.8 kg/m~2。     

山女鳟人工繁育技术试验

本研究系统介绍了山女鳟人工繁育的主要技术要点，从山女鳟的亲鱼选择及培育、人工采卵、人工孵化等方面进行了系统介绍。本次研究内容主要来自黑龙江水产研究所渤海冷水性鱼类试验站的山女鳟人工繁育的主要过程及一些相关资料。池养山女鳟2年性成熟，产卵排精后死亡率很高，寿命2—3年，多为2年，及少可达4年。山女鳟繁殖时间是10月至11月份，繁殖水温在13℃以下，水温15℃左右开始产卵，怀卵量与鱼体大小成正比例，多在300粒左右，卵重占鱼体重的23—24％。满2年的山女鳟大的可达500g左右。416g重亲鱼，可采卵1360粒，760g重的亲鱼，可采卵2799粒。卵为端黄卵，球形，沉性。直径3．5—6．0mm。卵黄淡黄色或橙黄色，受精卵孵化积温达200℃进入发眼期，积温400℃破膜孵出。人工养殖条件下山女鳟1周年生长最高可达130g，平均值为56g。采用挤腹采卵，取精，干导法人工授精，待受精止水膨胀后放入桶式孵化器进行流水孵化。     

山女鳟生物学及其养殖

黑龙江水产研究所于1996年12月从日本东京水产大学和新潟县内水面水产试验场引进山女鳟Oncorhvnchus ma-sou mason发眼卵1.2万粒。经3年多试验养殖,从发眼卵至亲鱼育成及人工繁殖取得了全人工养殖的成功。证明我国的冷水资源适于山女鳟的生长、发育和成熟,山女鳟可以成为我国养鳟业的新品种。在日本,20余种鲑鳟鱼类,山女鳟和大鳞大麻哈鱼被认为是最好吃的2种鱼,其特点是肉质细嫩,鱼味浓郁。又因其形体姿态优美、适于游钓而倍受青睐,自古就称其为“山女鱼”、“山溪女王”,是最受欢迎的淡水游钓鱼类。60年代做为日本政府计划山女鱼被开发成养殖鱼类。引进后取名为山女鳟。     

山女鳟同工酶的研究

采用淀粉凝胶电泳方法，对山女鳟的肝脏、肌肉等组织的LDH、MDH、IDH、ADH、EST、SOD等同工酶进行电泳，并对其表型进行生化遗传分析。结果表明，在检测到6种同工酶是由13个基因座位编码；其中m-MDH基因座位呈多态，其多态座位比例为7.6%，平均杂和度为0.059。在生化遗传水平上山女鳟表现出较低的遗传变异。     

山女鳟早期发育及低温耐性观察

将发育积温242℃.d的山女鳟发眼卵置山溪中进行流水孵化。在日均水温4.8℃环境下,发育积温达382℃.d时开始有少数鱼苗孵出。此后在日均2.3~1.5℃,最低0.2℃环境下历时36d,发育积温达456℃.d时全部孵化出膜,孵化率90.2%。最早出膜的孵化稚鱼在日均水温1.5~3.7℃,最低0.2℃环境下历时93d,发育积温达668℃.d时开始上浮。受精后172d发育积温达762℃.d时全部上浮,上浮率77.3%。驯饲一个月的稚鱼育成率63.2%。雏鱼孵化及形态机能发育正常,表明山女鳟在日均水温4.8~1.5℃,最低0.2℃的低温环境中可以正常地进行早期发育。     

山女鳟人工受精孵化技术初步研究

从日本引进的山女鳟发眼卵育成亲鱼后,以挤腹法采孵,取精,干导法人工受精,经30－60分钟止水膨胀后入桶式孵化器进行流水孵化,发展率25．2％,孵化稚鱼畸形率5．1％,患脐囊白点症的占7．3％,稚鱼体质软弱,受精后1－分钟内采用免膨法将卵将卵直接入桶孵化,发眼率59．4％,孵化稚鱼98％以上发育正常,畸形率3．6％,水质澄清孵化水温12℃试验组发眼率95．1％,孵化率94．0％,孵化稚鱼体质良好。     

山女鳟耗氧量与体重、水温的关系的研究

通过对体重0．53g和75．58g的山女鳟，在7℃、10℃、13℃、16℃、19℃，5个范围耗氧的测定，研究了山女鳟耗氧量与体重、水温的关系，结果表明：耗氧量随着体重和水温的增加而增加，耗氧率随着体重的增加而减少，在13℃-16℃水温范围内，水温增加但耗氧率增加不明显，水温在16℃时，耗氧量与体重的关系为：R=0．3621W^7848(R：耗氧量mg／h．尾，W：体重，g)，在体重0．53g时，耗氧量与水温的关系为：R=0．0173T-0．0393，75．58g时，耗氧量与水温的关系为：R=0．825T-1．725(R：耗氧量mg／h．尾，T：水温，℃)。山女鳟耗氧率具有昼夜变化，表现出明显的节律性，在13：00时耗氧率达到最高值，22：00时达到最低值。山女鳟的窒息点在1．2—1．98mg／L。     

人工养殖山女鳟幼鱼的生长特性

于2004年5月30日-2005年2月30日对人工养殖条件下山女鳟(Oncorhynchus masou masou)的生长特性进行观察,观察阶段为山女鳟初孵鱼苗至11月龄。实验期间水温为自然常温(4.7~16.8℃)。结果表明:在这一生长阶段,山女鳟体质量瞬时增长率与水温变化有关,体质量增长量和增长率随水温的升高而加快,高峰出现在5月龄(2004年8月),水温为16.83℃,但山女鳟的最适生长温度还有待进一步研究确定;体质量增长量、相对增长率与体质量瞬时增长率的变化相一致;山女鳟的生长指标和生长常数在人工养殖条件下变化一致,并显现出规律性;从体长和体质量之间的关系可认为山女鳟幼鱼阶段体长和体质量的生长基本同步,生长式型为匀速生长;山女鳟幼鱼阶段的肥满度与水温变化不一致,随着月龄的变化而波动;饲料的营养配比满足不了各个生长期的营养需求,因此,对山女鳟营养需求及配合饲料的研制还有待进一步的研究。[中国水产科学,2007,14(1):160-164]     

光照强度对人工养殖的山女鳟幼鱼生长性能的影响

在水温12.1～13.9°C下和直径80 cm、高60 cm,水深40 cm的圆形选育缸中研究了不同光照强度(1200lx、600 lx和300 lx)对平均体质量为10.10±0.8g的山女鳟(Oncorhynchus masou masou)幼鱼生长和存活的影响。结果表明,光照强度显著影响山女鳟幼鱼特定生长率(SGR)、肥满度(CF)和变异系数(CV)(P<0.01),高光照强度组SGR和CF值显著高于两个低光照强度组,而CV值则是高光照强度组显著低于两个低光照强度组;高光照强度组摄食率(FI)明显高于两个低光照强度组。实验表明,适度增强光照强度有利于山女鳟幼鱼的生长,这对于优化山女鳟幼鱼培育条件具有指导意义。     

开发山女鳟增殖游钓业的可行性

近年来北京地区在发展养鳟业的同时开发了虹鳟池塘游钓业,从其兴旺景象可以想象到随着社会生活的进步,将会出现更具文化气息的鳟鱼增殖游钓业,人们会在游戏山河、垂钓鳟鱼之中去体味贴近自然的鱼水情趣。我们曾有机会了解了一些日本的山女鳟河溪增殖游钓业的情况,受其启发认为这项产业在中国也会有很大的发展空间。本文试图通过对山女鳟产业的开发及山女鳟生态习性等情况的介绍来说明开发这项产业的可行性。     

图们江马苏大麻哈鱼陆封种群在不同地区的繁殖力比较

在图们江中采集野生陆封马苏大麻哈鱼Oncorhynchus masou(Brerart),经人工养殖、繁殖获得苗种后,引种到山东、北京等地进行培育和养殖,待性成熟后再进行人工繁殖。122尾样本的统计结果表明:体质量(512±206)g的亲鱼绝对怀卵量为(1 485±797)粒,相对怀卵量(2.72±0.47)粒/g,成熟系数(20.97±3.57)%,发眼率为50%~86%,孵化率32%~88%;卵巢质量、绝对怀卵量、相对怀卵量、成熟系数与体质量存在正相关线性关系;与野生种群及原产地池养相比,体质量和繁殖力明显提高。     

In vivo and in vitro effects of Rhizopus extract on body growth and steroid production in masu salmon, Oncorhynchus masou Brevoort

This study investigated the in vivo and in vitro effects of Rhizopus (filamentous fungus) extract (RU) in masu salmon Oncorhynchus masou Brevoort. Underyearling fish were fed with RU for 16 months. Monthly changes in body growth, gonadal maturation and serum levels of sex steroids were monitored. Gonads were also incubated at 0, 1, 10, 100 and 1000 μg RU mL⁻¹ Leibovitz's L‐15 medium for 18 h. The levels of steroids in serum and cultured medium were measured. It was determined that RU‐fed immature and mature males, when compared with control groups, showed significantly higher body growth during spring, summer and the spawning period. Similarly, immature RU‐fed females showed significantly higher fork length and body weight in autumn, spring and summer. Furthermore, RU‐fed males showed significantly higher levels of serum testosterone (T) and 11‐ketotestosterone (11‐KT) levels in the pre‐spawning season, and 17α, 20β‐dihydroxy‐4‐pregnen‐3‐one (DHP) in the spawning season. In vitro RU incubation of gonads showed a dose‐dependent and significant increase in T, 11‐KT, oestradiol‐17β and DHP release in the medium. It appears that the causes of enhanced body growth and increased steroid production herein observed in salmonids are the physiologically active substances that may be present in the mycelium of the fungus.     

Olfactory nerve response of masu salmon (Oncorhynchus masou Brevoort) and rainbow trout (O. mykiss Walbaum) to clove oil and MS-222

Two anaesthetics, clove oil and methane sulphonate (MS-222), were examined for their effects on the olfactory nerve response of masu salmon ( Oncorhynchus masou Brevoort) and rainbow trout ( O. mykiss Walbaum). Exposing both species to clove oil for 3 min at concentrations of 50 and 100 mg L⁻¹, or for 10 min at 50 mg L⁻¹, did not significantly reduce their olfactory response. Directly applying clove oil anaesthesia to the olfactory epithelium significantly reduced olfactory response though after 20 min, olfactory response recovered to 70% and 52% of pre-treatment levels in masu salmon and rainbow trout respectively. Compared with the post-anaesthetic recovery of responses after clove oil (50 mg L⁻¹), buffered MS-222 (100 mg L⁻¹) with NaHCO₃ (100 mg L⁻¹), and unbuffered MS-222 (100 mg L⁻¹) treatment for 3 min, the response after MS-222 treatment declined gradually and significantly, but not after clove oil and MS-222+NaHCO₃ treatments. Clove oil appears to be an effective and relatively safe anaesthetic for salmonids with little long-term impact on their olfactory response, which plays a crucial role in their life history.     

The effect of cortisol administration on blood plasma immunoglobulin M (IgM) concentrations in masu salmon (Oncorhynchus masou)

Immunoglobulin M (IgM) is known as a main factor in the humoral immune system of teleosts. In the present study, the effect of cortisol on plasma IgM concentrations was investigated using a specific antibody to IgM in masu salmon (Oncorhynchus masou). Cortisol was orally administered each day for 2 weeks at a dose of 1 mg g⁻¹ in the diet, and for the following week the fish were fed a non-treated diet. Blood plasma samples were collected at 0, 1, 2 and 3 weeks after the initiation of treatment. Oral administration of cortisol elevated plasma cortisol concentrations to about 40 ng/ml for 2 weeks after administration and slightly reduced plasma IgM concentration; the suppression was statistically significant one week after the period of hormone administration. However, treatment with cortisol did not affect plasma concentrations of total protein or α1-protein, one of the major serum proteins, during the experimental period. These results indicate that cortisol specifically suppresses plasma IgM concentrations.     

Use of microsatellite DNA and amplified fragment length polymorphism for Cherry salmon (Oncorhynchus masou) complex identification

Formosa landlocked salmon (Oncorhynchus masou formosanus), an endemic, critically endangered subspecies of Cherry salmon (Oncorhynchus masou) complex, is only found in Taiwan. Because the eyed eggs and ungutted carcasses of Pacific salmons (genus Oncorhynchus) are imported for aquaculture and food to Taiwan from overseas every year, the requirement for preventing illegal trade or accidental commercial imports to avoid unwanted fish from contaminating the gene pool of Formosa landlocked salmon and infect them with diseases is critical for the conservation of Formosa landlocked salmon. Traditional morphology‐based species identification is impossible for salmon eggs and larvae that lack clearly defined morphological features. In the present study, the genetic differences among four subspecies (Oncorhynchus masou ishikawae, O. masou subsp., Oncorhynchus masou masou and O. masou formosanus) of Cherry salmon complex were determined from microsatellite DNA and amplified fragment length polymorphism analyses. We successfully generated a genetic marker to aid traditional taxonomy and investigate the integrity of the current taxonomic status among members of Cherry salmon complex. Use of molecular markers, in combination with traditional morphological identification, is a promising tool for identifying four closely related subspecies of Cherry salmon complex.