草亲鱼烂尾病的发生及防治技术

草鱼烂尾病又称尾柄病，其传播快、死亡率高。草亲鱼患烂尾病实属罕见。但若治疗不及时或防治不得法，将会导致草亲鱼死亡，造成重大经济损失。自１９９１年以来，我场草亲鱼曾４次发生烂尾病。我们经几年的摸索，采取综合防治措施，效果显著。现总结如下。１发病情况１９９１年８月，我场１２口２．１公顷亲鱼池中有５口首次发现了草亲鱼烂尾病，虽经治疗仍死亡３５尾。１９９２年７月底又发生烂尾病，死亡７尾。１９９３年２月，我场淘汰了原有全部草亲鱼，进行了清塘消毒，启用了１７５组后备草亲鱼。１９９６年８月中旬，我们再次发现了…     

草亲鱼出血病的治疗

草亲鱼出血病的治疗１９９４年６月，我场草鱼繁殖结束，亲鱼转池后十余天就出现了草亲鱼严重死亡现象，经确诊为草鱼病毒性出血病。一、症状：６月１６日早晨，１０号池就出现了４尾草亲鱼死亡，１１号池也有３尾死亡，并有数十尾病鱼浮边，两池亲鱼基本上停止吃食。病鱼...     

草亲鱼打印病的防治

草亲鱼打印病的防治前几年，我场草亲鱼曾经患过打印病，经综合防治已经痊愈，且产卵量不仅不低于未患病前，甚至大大超过以前。现将我们的防治方法介绍如下：一、症状１．草亲鱼的打印病类似鲢鳙鱼的打印病，但又不完全相似。病鱼腹部两侧，离尾鳍约５～１０ｃｍ处，出现...     

大口鲶亲鱼打印病的防治方法

大口鲶又名南方大口鲶、河鲶等．属鲶科．是大型经济鱼类。笔者1995年在广东省潮阳市中顺苗种场工作期间．观察到蓄养的大口鲶亲鱼及后备亲鱼发生了打印病。而大口绍亲鱼打印病及防治尚未见报道。故将发病、防治情况报道如下：一、鱼池基本情况中顺苗种场所租用的亲鱼池位于潮阳市河溪镇养鳗场．共三口，原为养鳗场旧成鳗池。面积均为650m2，水源为蓄水池水．平均水深1．1m，PH值6．2-6．7．透明度25─30cm，沙土底质，池壁表面粗糙。二、发病情况病鱼是在1995年5月3日拉网检查亲鱼成熟情况时发现的，三地均有发病现象。1号池共捕亲鱼34尾…     

草鲢鳙亲鱼打印病的防治方法

笔者在地区淡水水产研究所从事亲鱼培育时，发现打印病对几种亲鱼危害严重，几乎百分之八十五的亲鱼患病。对此，进行观察并采取了以下综合防治措施。     

亲鱼的病害防治

亲鱼细菌性烂鳃、肠炎、赤皮病用漂白粉和大蒜或五倍子进行预防。打印病按每立方米水体用１克漂白粉全池泼洒预防。锚头鳋病按每立方米水体用０．５克９０％晶体敌百虫，间隔２周，连续全池泼洒２～３次进行预防和控制。另外，要防止产后亲鱼死亡。操作不细心，造成严重机械损伤；亲鱼成熟度选择不当，性腺发育未达到催产水平而催产。这两种情况都容易引起亲鱼产后死亡。还有催产剂用量过大，也可导致亲鱼死亡。防治方法如下：１．拉网操作要小心，避免鱼体受伤。尽量减少拉网次数，减少亲鱼受伤的机会和体力消耗。拉网进行角度要遵照操作规…     

用敌百虫、高锰酸钾合剂和漂白粉治疗草亲鱼打印病

草亲鱼打印病是人们常见的一种鱼病，其症状；亲鱼肛门附近的两侧皮肤、肌肉发炎出现红斑；病灶形状有圆形、椭圆形，严重者有1—2方寸大小的鳞片脱落，肌肉充血发红。感染了此病的亲鱼食量减少，体质受到极大的影响。对此，过去我们采取多种治疗措施，但效果欠佳。1986年我们改用敌百虫、高锰酸钾合剂和漂白粉综合治疗草鱼打印病，收到了良好的效果。     

介绍一种快速治疗亲鱼中华鳋病的方法

今年5月24日，我场在检查17号塘韵鲢亲鱼时，发现该塘原有的75尾亲鱼都不同程度的患了中华鳋病(发病率100％)。病情严重的亲鱼，两侧鳃丝白白的一层呈棉絮状，在孵化季节这么高的发病率在我场还从未有过。查阅资料，对此病的治疗方法，多数是用硫酸铜、硫酸亚铁合剂或敌百虫、硫酸亚铁合剂全池泼洒，但治疗时间较长，     

亲鱼的产后护育

亲鱼的产后护育繁殖期间，亲鱼损伤很大，严重的还影响第二年繁殖，尤其是人工授精的亲鱼。我们场１９８８─—１９９１年期间，亲鱼每年繁殖完以后，有９０％由于严重的赤皮病，满身的锚头鳋和鱼鲺影响其性腺的发育，致使第二年无法繁殖。１９９１年后，我们经过分析和总...     

家鱼人工繁殖期亲鱼疾病的综合防治

亲鱼在人工繁殖时,往往因拉网次数过多,雌雄比例失调及条件的限制,而不得不采取人工授精,加之不细心操作等原因,很容易造成鱼体创伤。亲鱼放入暂养塘后,受伤处如果得不到很好处理,就容易受到病菌的感染,一般最易患水霉病、打印病、腐皮病、烂尾病。亲鱼产后体质虚弱,入塘后还易     

嘉陵江渠化对主要经济鱼类产卵场的影响

为探究嘉陵江渠化对主要经济鱼类产卵场的影响,2019年3-4月,采用历史资料搜集、访问调查和实地勘察的方法,并结合DNA条形码技术鉴定野外采集的样品。结果显示,原有60个主要经济鱼类产卵场中,41个已经消失,14个存在但已经发生改变,只有5个基本未改变;从产卵场数量、类型和规模来看,均呈减少趋势,仍存在的主要为鲤（Cyprinus carpio）、鲫（Carassius auratus）产卵场。共鉴定鱼卵1 362粒、鱼苗539尾,隶属2目2科12种。鱼卵仅3种,其中,鲤1039粒,占比76.28%;鲫312粒,占比22.91%;红鳍原鲌（Cultrichthys erythropterus）11粒,占比0.81%。鱼苗11种,包括鲤、鲫、马口鱼（Opsariichthys bidens）、麦穗鱼（Pseudorasbora parva）、峨眉鱊（Acheilognathus omeiensis）、大鳍鱊（Acheilognathus macropterus）、兴凯鱊（Acheilognathus chankaensis）、?（Hemiculter leucisculus）、短须颌须鮈（Gnathopogon imberbis）、子陵吻虾虎鱼（Rhinogobius giurinus）、粘皮鲻虾虎鱼（Mugilogobius myxodermus）;其中,兴凯鱊最多,有372尾,占比69.02%;其次为鲫59尾,占比10.95%;鲤57尾,占比10.58%;其他占比仅9.46%。研究表明,产卵场的改变主要集中在水文情势、河床底质和水生植物等方面,梯级水电站开发和采砂作业等导致河道变宽、水位上升、流速降低、卵石漫滩等生境消失、水生植物生物量减少,是原有产卵场消失或改变的主要原因。     

Spontaneous maturation and spawning of milkfish in floating net cages

Milkfish (Chanos chanos Forsskal) reared from wild-caught fry and from hatchery-bred fry matured at 3.5–5.5 years (2.3–4.9 kg). Maturation and spawning of the hatcherybred fish marks the first time the milkfish life-cycle has been completed in captivity.Milkfish at various stages of gonadal development were obtained in July–October 1980 and March–June 1981 derived from wild-caught fry, and in February–June 1983 from the hatchery-bred fish. The fish were held in floating net cages 9 m and 10 m diameter by 3 m deep, located in 7 m deep water off Igang, Guimaras Island, Philippines. Annual ranges of temperature and salinity were 25–33°C and 25–38 ppt, respectively. The fish were fed commercial feed pellet (42% protein) at 1.5–2% of body weight twice daily.Sexual maturation occurred during the natural breeding season of wild milkfish in the nearby waters. Gonadosomatic index (GSI) of mature males was 0.32–3.95 (wild-caught, 0.32–3.95; hatchery-bred, 1.71–3.85). For mature females it was 1.24–8.12 (wildcaught, 1.56–7.62; hatchery-bred, 1.24–8.12). Two spawnings were recorded in August 1980 and eight in May–July 1981 from the broodstock derived from wild-caught fry, with 342–6293 eggs collected from each spawning, while 14 spawnings were observed in May–June 1983 from the hatchery-bred fish, with 770–114 000 eggs collected. The time of spawning was between 23.00 and 02.00 h. Fertilization rate was 55–99% for the broodstock from wild-caught fry and 47–100% for the hatchery-bred fish. Hatch rate varied from 9 to 80%.Factors affecting spontaneous maturation, spawning and rematuration are discussed. Although slight improvements in egg collection were obtained, further innovations in egg collecting techniques will have to be developed. The results indicate the potential for hatchery production of milkfish fry from captive broodstock and for restocking of waters deprived of naturally occurring fry.     

Passive transfer of protective immunity against ichthyophthiriasis from vaccinated mother to fry in tilapias, Oreochromis aureus

Tilapias, Oreochromis aureus, were vaccinated twice with live tomites of Ichthyophthirius multifiliis in physiological saline 1 month before spawning (test group). A control group was similarly treated but with physiological saline only. Fertilized eggs were collected from the mouths of both groups and incubated until the young reached the free-swimming stage. Free-swimming fry were also collected immediately after they were expelled from the mother's mouth in other fish of the two groups. The fry were exposed to infective tomites of I. multifiliis and thereafter returned to their holding tanks. All fry obtained from the controls without mouth-brooding died after tomite exposure. However, fry with mouth-brooding before tomite exposure showed 37.3% survival. On the other hand, fry obtained from vaccinated broodstock without mouth-brooding exhibited 78.4% survival which increased to 95.3% with mouth-brooding. The protective immunity is correlated with the titres of anti-I. multifiliis antibodies in the soluble extracts of fry tissues and the mother's plasma. The results clearly indicate that protective immunity against ichthyophthiriasis “ich” in tilapia fry can not only be derived directly from the mother via eggs but also be acquired indirectly from the mouth cavity during the brooding period. The results thus suggest that proper vaccination of mothers before spawning would effectively protect fry against a protozoan disease.     

Improving spawning synchrony in the Nile tilapia, Oreochromis niloticus (L.)

Abstract. The development stage and number of seed (eggs and fry) removed from individual incubating Oreochromis niloticus (L.) broodfish at 10-day interharvest intervals (IHI) was compared with the harvest of free-swimming fry from undisturbed fish held in a tank within the same system. Spawning synchrony and productivity were compared for (1) total exchange of females for ‘conditioned’ females after each harvest, (2) exchange of only spawned females, and (3) return of females back into the spawning tank. Improved synchrony and seed production were positively related to removal of eggs and fry from incubating females and could have important implications for broodstock management in commercial hatcheries. Allowing fish to remain undisturbed in clear water tanks may lead to inhibition of spawning activity related to the formation of hierarchies. Individual weight loss by females during incubation was correlated with stage of seed harvested and thus with timing of spawning during the interharvest interval.     

鳜鱼人工繁殖及苗种培育技术初步研究

鳜鱼亲鱼的培育,重点是投喂适口、数足的饵料鱼;亲鱼的选择用外观法并结合挖卵观察,催产采用一次注射PG(或RES)+混合A型激素,用自然产卵受精的方法;提高鳜鱼苗成活率在于开口时能供给个体适宜的团头鲂及各期饵料鱼。     

花[鱼骨]人工繁殖技术的研究

本文主要研究了花[鱼骨]的繁殖生物学和人工繁殖技术。经过实验摸清了花的性成熟年龄和成熟最小型,性腺的发育状况,花的繁殖力、产卵时间和水温、雌雄鉴别等;比较了不同催产药物对花的催产效果,2008年催产率达100%,受精率95.3%,孵化率95%,获鱼苗14.12万尾。     

Survival of stocked hatchery-reared brown trout, Salmo trutta L., fry in relation to the carrying capacity of a trout nursery stream

Abstract. During the period June 1982-84 hatchery-reared brown trout, Salmo trutta L., fry were Stocked into stretches of the Owendoher. a trout nursery stream on the east coast of Ireland. These experiments were designed to examine the survival of stocked fry and to estimate the carrying capacity of the system. During the first year fry were stocked into sectors already supptorting wild fish at densities normal for the system. In the following year fry numbers were artificially reduced prior to stocking with the hatchery-reared fish. Mortality of the stocked fry was high after release with less than 33% of the fish surviving beyond the first 3 weeks. No stocked fish survived after October 1982. In the second year, however, 2-9% of the fish survived. The best survival rates were achieved where wild fry numbers were lowest. Regardless of the initial stocking density the various experiments yielded autumn fry densities (0.07-0.7 fish/m²) similar to those at unstocked sites (0.1-0.62 fish/m²).
Stocking did not increase recruitment to the 1+ group and again 1+ densities (0.15-0.35 fish/m²) similar to unstocked sites (0.07-0.39 fish/m²) were obtained at the end of each year. These results suggest that spawning and recruitment in the Owendoher yield population densities approaching the maximum carrying capacity of the stream. The system appears to support a maximum summer fry density in the region of 1 fish/m² and a maximum autumn density of 0.7 fish/m².     

翘嘴红鱼白人工繁殖及其夏花鱼种培育技术研究

对翘嘴红鱼白亲鱼的池塘驯化培育和人工繁殖技术以及夏花鱼种的培育技术进行了研究。在池塘对亲鱼进行人工培育,使其性腺发育达到成熟,经催产繁殖鱼苗获得成功,再对鱼苗进行池塘培育后获得夏花鱼种２１．５万尾。     

Predation on native fish eggs by invasive round goby revealed by species‐specific gut content DNA analyses

1. Conservation of riverine fish often aims to improve access to spawning grounds and restore longitudinal connectivity by removing migration barriers, and involves substantial investments. However, these investments also enable non‐native predators to invade upstream into spawning areas and potentially adversely affect the recruitment of threatened freshwater fish through egg or fry predation.
2. Detecting egg predation is often challenging. Visual inspections of fish gut contents may underestimate predation of soft materials such as eggs and fry, which limits the discovery of predators preying upon these life‐stages. DNA‐based detection assays may offer a more sensitive tool to assess predation of soft materials.
3. A conservation issue was confirmed by developing and applying a species‐specific DNA‐based detection assay: invasive round goby (Neogobius melanostomus) prey on the eggs or fry of the threatened common nase (Chondrostoma nasus) in Switzerland.
4. DNA‐based detection assays were also developed for five other valuable native fish species, including endangered salmonid and cyprinid river spawners. The applicability of the assays was confirmed in a series of laboratory and field feeding experiments involving eggs and fish tissue. In addition, this work provides a guiding framework for conservation managers regarding the use and applicability of different DNA‐based detection approaches for gut content analysis.
5. The results of this study could inform local conservation measures – such as temporary reductions in the density of round goby at spawning sites prior to spawning – and demonstrate how targeted application of species‐specific molecular markers may advance freshwater fish management.

     

双斑东方鲀全人工繁殖试验

对野生双斑东方鲀(Takifugu bimaculatus)人工繁殖的子一代进行人工培育,雌鱼须经三年性腺成熟,成熟系数为17.55%,雄鱼性腺成熟为两年。产卵前一个月,雌亲鱼经强化培育、催熟后,成熟系数可达到25.00%。对7组亲鱼注射LRH-A_2激素,共获鱼苗1.2048×10~6尾,其中全人工繁殖鱼苗9.592×10~5尾,对照组获鱼苗2.456×10~5尾。并就双斑东方鲀性成熟年龄等进行讨论。