春季繁殖鮸鱼亲鱼血清中雌二醇、孕酮和睾酮水平变化分析

模拟鮸鱼自然繁殖生境,采用调控水温、光照,并结合注射生物激素,促使鮸鱼在春季达到性成熟,以春季繁殖鮸鱼亲鱼为材料,检测了其血清中雌二醇(E2)、孕酮(P)和睾酮(T)变化情况。结果表明:1~3月,E2、P和T含量很低;从4月份开始E2、P和T含量逐渐上升;5月份E2、P和T的含量急剧上升,最大值分别到达416.8±254.6 pg/ml、1.75±0.41 ng/ml和0.39±0.18 ng/ml;6月份E2、P和T维持较高的含量;多次催产后到7月份,E2、P和T明显下降,均处于较低水平。说明E2、P和T的检测较准确地反映了人工控制条件下春季繁殖鮸鱼亲鱼的生殖生理活动。     

利用地下采矿水养殖棘腹蛙的初步研究

对地下采矿水养殖的棘腹蛙在翌年的繁殖行为、产卵时间、产卵量、受精率与孵化率以及水温、pH值等进行了观察记录,并对养殖水温和翌年棘腹蛙的繁殖情况进行了曲线估计回归分析。研究结果显示:在利用地下采矿水人工养殖的条件下,棘腹蛙在翌年能正常繁殖,其最适繁殖水温为21～23℃;最初产卵时间由原来的5月份提前到2月份,繁殖期由原来的5～9月份延长到2～9月份;繁殖高峰期在5～6月。     

棘腹蛙规模化人工繁殖技术的研究

棘腹蛙(Paa boulengeri)营养价值高,是一种重要的经济动物,为了充分利用湖南省宁乡县的地下采矿水,变废为宝来养殖棘腹蛙,为棘腹蛙的人工规模化养殖提供基础数据,作者于2007年8月～2008年10月,在位于湖南省宁乡县煤炭坝镇的长沙棘腹蛙繁育研究中心内,对地下采矿水养殖的棘腹蛙在翌年的繁殖行为、产卵时间、产卵量、受精率与孵化率以及水温、pH值等进行了观察记录,并对养殖水温和翌年棘腹蛙的繁殖情况进行了曲线估计回归分析。研究结果显示:在利用地下采矿水人工养殖的条件下,棘腹蛙在翌年能正常繁殖,其最适繁殖水温为21～23℃;最初产卵时间由原先的5月份提前到2月份,繁殖期由原先的5～9月份延长到2～9月份;繁殖高峰期是在5～6月份。     

半滑舌鳎亲鱼培育技术研究

2003—2006年进行了半滑舌鳎亲鱼培育试验。试验结果表明,半滑舌鳎雌鱼生长速度明显超过雄鱼;通过强化饵料营养和调控水温、光照等技术,亲鱼可自然产卵,产卵期27~32 d;雌亲鱼近3周龄时首次性腺成熟;产卵量、受精率和孵化率随亲鱼年龄的增长而提高;半滑舌鳎亲鱼在20℃以下时仍可产卵、受精,但受精卵不能孵出仔鱼。     

浙南飞云江口棘头梅童鱼的资源调查和研究

对浙南瑞安飞云江口海域的棘头梅童鱼的繁殖习性、资源变化、生长、食性等进行了调查和研究。每年5~6月,棘头梅童鱼向飞云江口海域产卵场集中进行产卵活动,未见有秋季产卵现象,产卵水温19~25℃,产卵多在大潮水的几天里,产卵一般持续3个潮水。     

河川沙塘鳢亲鱼培育及促熟产卵技术研究

为研究河川沙塘鳢亲鱼培育和促熟产卵技术,满足其大规模养殖生产的苗种需求,2011-2012年,在池塘条件下,进行了河川沙塘鳢亲鱼强化培育和繁殖试验,并在产卵规律和采卵技术方面进行了探索。结果表明,在自然环境条件下,通过亲鱼的优选、培育期水流控制、各阶段饵料营养强化等一系列调控措施,可促进亲鱼性腺发育,使其达到性成熟并自然产卵。河川沙塘鳢亲鱼在水温达到15℃时开始产卵,其最适产卵水温为18~20℃,水温高于22℃时,产卵量开始下降。整个产卵期自3月下旬至5月初,其中4月份为产卵高峰期。试验共获得鱼卵48.9万粒,其中4月份获得鱼卵37.5万粒,受精率为66.7%,而3月份和5月份不仅产卵量少,受精率也明显较低。     

鄱阳湖翘嘴鳜规模化繁育及健康养殖技术综述

优选野生鄱阳湖翘嘴鳜成熟个体为亲本,强化培育至5月初开展人繁。♀:♂=1∶1~1.5,一次性注射混合激素,自然产卵,雌体剂量为LRH-A10~12ug HCG700~800 IU/kg。水温23~25℃时效应时间25~27h,催产率90~100%,受精率50~60%,孵化率85%以上,水温24~26℃需30~31h出膜。采用同步繁殖的团头鲂苗作开口饵料鱼,采取投喂充足的适口饵料鱼、严防低溶氧综合症和NH3-N中毒、遍洒福尔马林和硫酸铜防治原虫病等措施,育苗成活率由20%提高到60~70%。针对滨湖地区和自然水体野杂鱼丰富的特点,总结了池塘套养、自然水体混养和网箱养殖商品鳜模式,探讨了池塘主养及饵料鱼配套技术,建立了健康养殖操作规程。     

乌苏里拟鲿人工繁育技术初探

为研究乌苏里拟鲿的人工繁殖和苗种培育技术,2011年5月和6月从吉林省鸭绿江地区采购两批亲鱼运回安徽进行了繁育试验。注射人工催产激素促熟催产,人工授精,水泥池流水孵化,土池施肥培水并用粉料培育鱼苗。试验结果:第一批次催产雌鱼260尾、雄鱼56尾,水温22.0～22.5℃,产卵率为35%,平均受精率55%;孵化水温19.5～23.0℃,因感染水霉,仅获得300多尾鱼苗。第二批次催产雌鱼275尾、雄鱼60尾,水温24.0～25.5℃,产卵率50%,平均受精率65%;孵化水温24.5～28.3℃,由于孵化期间使用亚甲基蓝防治水霉,孵化率达到75%。两个批次共繁殖鱼苗19万尾,培育出全长4.5～5.5cm的鱼种6万尾,培育成活率31.58%。     

用人绒毛膜促性腺激素（HCG）诱导鲻鱼产卵

Shehadeh和Ellis(1970)报导过在鲻鱼自然繁殖季节期(12—2月,夏威夷),用鲑鳟鱼脑垂体,结合用Synahorin [Teikoku激素Mfg．Co]对鲻鱼进行注射,诱导产卵,获得成功。     

国外简讯

美国试养裸首梳唇隆头鱼　　将捕获的裸首梳唇隆头鱼暂养在黑色水槽中 ,设置气石并以 PVC管作隐蔽物。水槽上方用黑塑料布遮盖 ,布下用日光灯照明。冬季 1 0 h光照 1 4 h黑暗。从 1 1月 2 5日养至翌年 3月 1 7日。投喂鱼、蟹、贻贝等饵料。 1 1～ 1 2月份水温 5.5℃～ 9℃ ,平均 7.4℃ ;1～ 3月份水温 3.8℃～7.8℃ ,平均 6℃。鱼躲藏在隐蔽物中基本不活动。 3月 1 7日将水温提升至 1 4℃ ,光照由 1 0 h增至 1 3h。隆头鱼于 3月 31日产卵 ,4月 2日有大批卵孵化。此试验将裸首梳唇隆头鱼的自然产卵期从 5～ 8月份提前至3月底。将初孵仔鱼分…     

Reproduction of Penaeus kerathurus using eyestalk ablation

In a preliminary experiment on the induction of sexual maturity in Penaeus kerathurus by unilateral eyestalk ablation, spawning was obtained in 94% of the females treated. The time necessary to reach the spawning stage appeared to be closely related to the stage of natural physiological development of the gonads and the length of the photoperiod, the period between ablation and spawning decreasing from 69 days for females treated in November to about 10 days for females treated at the beginning of their natural reproductive period in May/June. Spawning after treatment was repeated up to eight times, sometimes at intervals of less than 10 days, without showing a decrease in the amount of fertile spawn. The mean number of fertile eggs per spawn was 78.400, which is not significantly different from the corresponding mean obtained previously after thermal stimulation of almost mature breeders; the hatching percentage, 67%, was also similar. Often only the anterior and median lobes of the ovaries are included in the spawning process. The discharged spawn is nearly always completely free of matrix material. It is anticipated that induction by eyestalk ablation could allow a considerable extension of the growing season and of the area suitable for culture.     

异齿裂腹鱼人工规模化繁殖技术研究

2010年4～6月,对野生异齿裂腹鱼(Schizothorax o' connori)人工规模化繁殖技术进行研究,并初步进行产后亲鱼恢复培养技术研究.对108尾雌鱼进行干法人工授精,共采卵104万多粒,孵出仔鱼62万多尾.其中45尾雌亲鱼自然成熟,共采卵46.8万多粒,平均受精率和孵化率低于人工催产雌鱼卵.人工催产83...     

Indoor Spawning and Egg Development of the Red Claw Crayfish Cherax quadricarinatus

In 1991 and 1992, indoor hatchery experiments were conducted with red claw crayfish Cherax quadricarinatus a large tropical crayfish from northern Australia. Six fiberglass tanks were stocked with 40–190 g mature red claw crayfish at 10/m² and a 1:2 male to female ratio. Water temperature was maintained at 28 ± 1 C. Photoperiod was provided by natural daylight in 1991 and controlled lighting in 1992.
With natural lighting, monthly spawning rates (% of females spawning/month) ranged from an average of 15% during months with less than 12 h of light per day to over 35% in months with more than 12 h of light per day. Peak spawning occurred from May to July, too late to obtain juveniles for spring stocking. During the second year, photoperiod was increased from 10L:14D in December to 14L:10D in February and maintained at this level until July. Red claw spawning increased with increasing day length. Peak spawning rates of 50% per month and higher occurred from March to May. Spawning rates decreased dramatically after May, even though photoperiod and temperature remained constant. Eggs per spawn increased with an increase in female size. Fecundity average 7.3 juveniles per gram of body weight for females from 40 to 190 g, regardless of size. Egg color was useful for predicting stage of development.     

Oocyte Development and Induced Spawning of Smallmouth Bass (Micropterus dolomieui) in Response to Photoperiod and Temperature Manipulation: Preliminary Results

Smallmouth bass ( Micropierus dolomieui ) in Quebec spawn between the end of May and mid-June. Wild broodstock (4 to 8 years old) and laboratory-reared ones (0+ years old) reared in a water recycling system were submitted to different temperature and photoperiod regimes to extend their natural spawning period. Oocyte maturation followed in vivo showed that oocytes developed to stage III in both cases but final maturation and ovulation was limited to the laboratory-reared bass and this, a month before the normal spawning period, at 20.5 cm TL. Exogenous factors are examined, specifically duration of long photoperiod and vital space related to non-spawning of wild broodstock.     

Effect of varying density and water level on the spawning response of African catfish Clarias gariepinus: Implications for seed production

The development of a reliable methodology for spawning of African catfish, Clarias gariepinus without the use of hormone injections would greatly improve the prospects of aquaculture in Africa. Earlier work has shown that it is possible to produce C. gariepinus fingerlings by subjecting the broodfish to a physical stress of reduced water depth and/or increased temperature. The hypothesis that C. gariepinus could be induced to spawn through a combined physical stress of lowered water level and increased stocking density was tested in concrete tanks. Three water levels (25, 50 and 75 cm) and three stocking densities (2, 4 and 6 pairs of broodfish at a 1:1 sex ratio in each hapa) were tested. Water depth in the tanks and brood fish density in the hapas affected spawning success. The percentage of spawning females was significantly higher when broodfish were stocked at 2 and 4 pairs in each hapa at water levels of 25 cm or 50 cm. There was no significant difference in spawning response between the 25 and 50 cm depths while a significant difference was seen between the 75 cm and both 25 and 50 cm depths. The results indicate optimum levels and densities for enhancing spawning success in C. gariepinus.     

Conservation of spawning time between years in lumpfish Cyclopterus lumpus and potential impacts from the temporal distribution of fishing effort

Lumpfish, Cyclopterus lumpus L., has an extended ovary development period and a relatively long spawning season. It therefore seems unlikely that individuals spawning later in the season would be able to recover from spawning and develop their gonads in time to spawn during the early part of the season the following year. The hypothesis that individuals spawning early or late in a spawning season would spawn early or late the following year was tested using fish tagged in Iceland between 2008 and 2017. The tagging date and recapture date the following year were positively correlated with an average of 356 days at large (DAL). Fish sampled from the fishery indicate that tagging/recapture date gives an indication of spawning time. From this, it was concluded that spawning time in the current year can be used to predict spawning time the following year. As fishing effort was greatest at the end of April/beginning of May, it seems likely that fish that come to spawn at this time will be subject to a higher fishing mortality. Therefore, they will be less likely to spawn successfully than fish spawning earlier or later in the year. If spawning time is under genetic control, then this could have consequences for the spawning phenology of lumpfish.     

Effects of photoperiod on growth and spawning efficiency of Nile tilapia (Oreochromis niloticus L.) broodstock in a recycling system

This study was conducted to evaluate the effects of photoperiod on the growth, feed conversion ratio (FCR) and spawning performance of Nile tilapia (Oreochromis niloticus) broodstock. Duplicate groups of two males (66±3.04 g) and six females (50.5±1.58 g) were stocked in 0.4 m³ fibreglass tanks in a recirculating water system at a male:female ratio of 1:3. The fish were subjected to four photoperiod treatments: 24:0 light:dark (L:D), 18L:6D, 12L:12D and 6L:18D. Light intensity was kept constant at about 2500 lx throughout the study. The fish were fed a commercial tilapia diet (35% crude protein and 16.6 MJ GE kg⁻¹) at a daily rate of 2–3% of tank biomass, twice a day, for 130 days. Males grew significantly faster than females under all photoperiod regimes. The best growth rate and FCR were attained at 18L:6D, followed by 24L:0D, 12L:12D and 6L:18D respectively. The number of eggs per female, number of eggs per spawn and number of spawnings per female were all significantly higher in the 12L:12D treatment than in all other photoperiod cycles. Interspawning intervals and days elapsed per spawn were also shorter in the 12L:12D treatment. The time to first spawning was slightly longer in the 24L:0D and 6L:18D than in 12L:12D and 18L:6D light phases. The 18L:6D and 6L:18D photoperiods produced the lowest spawning performance. It is concluded that a 12L:12D photoperiod regime should be adopted for maximum fecundity, seed production and spawning frequencies of Nile tilapia broodstock reared in intensive, recirculating systems. If maximum reproduction is desired, a near‐natural day length photoperiod should be used.     

Captive breeding of climbing perch Anabas testudineus (Bloch, 1792) with Wova-FH for conservation and aquaculture

Induced breeding of climbing perch, Anabas testudineus was conducted by synthetic hormone Wova‐FH in the intensity level of 0.1, 0.2 and 0.3 mL kg^?1 of body weight respectively. The brooders were injected one time and left to spawn in the spawning hapa in the sex ratio between male and female as 2:1. It was found that at all the intensity level hormone Wova‐FH could enhance the fishes to breed and lay eggs whereas no breeding was observed in control set. The spawning time, quantity of the brooder spawn, fertilization rate, hatching rate and survival rate were quantified in each set of experiment. The egg output/female was significantly higher in 0.3 mL in comparison with 0.1 and 0.2 mL kg^?1 of body weight. The statistical analysis showed significant (P≤0.05) effect between hormone dose on fertilization rate, egg output and hatching rate. The present experiment suggests that Wova‐FH at the dose of 0.3 mL kg^?1 body weight of fish is more effective which might be considered for raising captive population.     

Reproduction of striped bass, Morone saxatilis (Walbaum), broodstock: monitoring maturation and hormonal induction of spawning

Abstract Levels of gonadal steroid hormones were quantified in an adult striped bass, Morone saxatilis (Walbaum), broodstock during their gametogenic cycle. Blood plasma concentrations of Estradiol (E₂) and testosterone in females, or 11-ketotestosterone(11-KT) and testosterone (T) in males, were used as indicators of maturation. In both sexes, hormone levels were low in summer but increased significantly by late October to intermediate levels which were then maintained until late January. They then increased again rapidly to maximum pre-spawning values attained in late February or March, and subsequently decreased during the spawning period (April and May) with an increased incidence of spent fish with low hormone levels. The changes in blood hormone concentrations coincided with annual changes in photoperiod and water temperature that may be useful landmarks for maturation in captive broodstock. Mature females were implanted with pellets containing a dose of approximately 20 μg/kg body weight of [D-Ala⁶-Pro⁹-Net]-LHRH (GnRHa) in a matrix of cholesterol (CH) and cellulose. In April, they had not yet begun final oocyte maturation (FOM) and were too immature for conventional induction of spawning by injection with human chorionic gonadotropin (hCG). In early April, females given two 95% CH (slow hormone-release) GnRHa pellets (95/95) or females given one 80% CH (fast hormone-release) GnRHa pellet and one 95% CH GnRHa pellet (80/95) spawned within 13 days treatment (n= 4) with good egg fertility (76 ± 7% of total) and hatch rates (62 ± 15% of fertile). Females given dual fast-release GnRHa pellets (80/80) or control (Sham) pellets did not spawn or show evidence of increased oocyte diameter or development. In late April, four of six females given the 80/95 GnRHa pellet combination spawned within 9 days. Three fish produced fertile eggs (54 ± 18%). one spawned overripe eggs, and the remaining two increased oocyte diameter and maturation. Three corresponding controls did not spawn, and two of these showed clear signs of atresia within 11 days. In early May, some females were undergoing early FOM and were mature enough to be spawned by hCG injection. Three were given a single 80% CH GnRHa pellet and spawned within 6 days of treatment to produce fertile eggs (44 ± 6%). Of two other females given dual 80% CH GnRHa pellets, one spawned infertile eggs and the other failed to spawn within 9 days. GnRHa implants show promise as a technique for inducing spawning of captive striped bass broodstock although the optimum hormone delivery systems, dosages and release rates should be verified for fish at specific maturational stages.