池养条件下似刺鳊(鱼句)早期发育阶段的摄食与生长特性

对人工培育的似刺鳊(鱼句)(Paracanthobrama guichenoti)仔鱼、稚鱼和幼鱼的生长与摄食节律进行了研究.结果显示,在1~70日龄间,似刺鳊(鱼句)全长平均日增长率为3.55%,体重平均日增长率为11.26%,头长/全长值随着13龄的增长而变小.全长(L,mm)与体重(M,mg)的关系式为M=0.001 2 L2-0.056 4L+0.650 4;体重(M,mg)与日龄(D,d)的关系式为M=0.004 3 e0.0936D;全长(L,mm)和日龄(D,d)的关系式为L=0.015 4 D2-0.012 8 D+8.196 5.在饵料充足的条件下,20日龄晚期仔鱼全天均有很高的摄食发生率,小高峰出现在8:00时;40日龄稚鱼则表现出明显的昼夜摄食节律,属于典型的白天摄食类型,日摄食率2.337 6%.20 13龄仔鱼和40日龄稚鱼饱食后分别经6 h、5 h整个消化道排空.在水温25℃及饥饿空胃状态下,10日龄仔鱼只经3 d即开始出现死亡个体,经5 d全部死亡;20日龄仔鱼经6 d开始出现死亡个体,经9 d全部死亡;40 13龄稚鱼经7 d才开始出现死亡个体,10 d后全部个体均死亡.     

池养条件下似刺鳊鮈早期发育阶段的摄食与生长特性

对人工培育的似刺鳊鮈（Paracanthobrama guichenoti）仔鱼、稚鱼和幼鱼的生长与摄食节律进行了研究。结果显示,在1～70日龄间,似刺鳊鮈全长平均日增长率为3．55％,体重平均日增长率为11．26％,头长／全长值随着日龄的增长而变小。全长（L,mm）与体重（M,mg）的关系式为M=O．0012L^2-0．0564L＋0．6504;体重（M,mg）与日龄（D,d）的关系式为M=O．0043e^0.0936D;全长（L,mm）和日龄（D,d）的关系式为L=0．0154D^2-0．0128D＋8．1965。在饵料充足的条件下,20日龄晚期仔鱼全天均有很高的摄食发生率,小高峰出现在8：00时;40日龄稚鱼则表现出明显的昼夜摄食节律,属于典型的白天摄食类型,日摄食率2．3376％。20日龄仔鱼和4013龄稚鱼饱食后分别经6h、5h整个消化道排空。在水温25℃及饥饿空胃状态下,10日龄仔鱼只经3d即开始出现死亡个体,经5d全部死亡;20日龄仔鱼经6d开始出现死亡个体,经9d全部死亡;40日龄稚鱼经7d才开始出现死亡个体,10d后全部个体均死亡。     

不同饵料密度和盐度下褶皱臂尾轮虫的生活史特征

为探索低盐驯化褶皱臂尾轮虫规模化培育的可行性,本实验以小球藻(Chlorella vulgaris)为饵料,在饵料密度1.0×10⁴、1.0×10⁵、1.0×10⁶、1.0×10⁷和1.0×10⁸ cells·mL^-1下,采用单个体培养法,研究了盐度23及盐度6的褶皱臂尾轮虫(Brachionus plicatilis)的生活史特征。结果表明：随着饵料密度的升高,两组盐度轮虫的生殖期、平均寿命、产卵量、生命期望、净生殖率、世代时间和种群内禀增长率均呈现出先升高再降低(P<0.05);盐度6的轮虫在饵料密度1.0×10⁶、1.0×10⁷和1.0×10⁸ cells·mL^-1下的生殖前期显著小于饵料密度1.0×10⁴和1.0×10⁵ cells·mL^-1下的生殖前期(P<0.05);盐度23的轮虫...     

食蚊鱼摄食特性及其与浮游动物和环境因子的关系

2008年11月—2009年4月,利用分时段采样法对广州暨南大学明湖内食蚊鱼在秋季(11月)、冬季(12—2月)、春季(3—4月)3个季节的摄食特性进行了研究,探讨其与湖内浮游动物群体数量动态、光照和水温的关系。结果表明:食蚊鱼主要以浮游动物为食,对枝角类和桡足类有较强的选择性;明湖日平均水温与浮游动物日平均丰度在3个季节间有显著差异,而食蚊鱼消化道饱满指数的差异不显著;食蚊鱼消化道饱满指数在这3个季节的变化与浮游动物丰度、水温、光照在这3个季节的变化无明显的相关;无论哪个季节,食蚊鱼在白天时段(10:00—18:00)的消化道饱满指数均高于夜间(22:00—6:00),表现出白天高峰型的摄食节律;光照是影响食蚊鱼昼夜摄食节律的主要因素,而水温、浮游动物丰度的昼夜变化与食蚊鱼的昼夜摄食节律没有显著相关。     

池养刀鲚(Coilia nasus)鱼种的摄食与生长

采用生长测量、摄食节律评估的方法研究了人工养殖备件下刀鲚(Coilia nasus)的摄食和生长特性,旨在为刀鲚积累基础生物学资料,同时为大规模开展刀鲚的池塘养殖提供参考.结果表明:经过153 d的生长期,刀鲚的平均体长从最初的(12.41±2.21 )cm增加到(21.25±2.08)cm,体重从(5.83±0.91)g增加到(40.58±12.98)g;体长与日龄为线性相关(L=0.0558t+13.102,R2=0.97),体重与日龄为指数相关(W=6.5699e0.01231,R2 =0.98),体重与体长之间呈幂函数关系(W=0.0006L3.5924)幂指数b值接近3;刀鲚鱼种有明显的昼夜摄食节律,4:00-8:00是刀鲚鱼种的摄食高峰期,12:00左右摄食活动基本停止,16:00起摄食强度又明显回升,属晨昏摄食;此外还发现,枝角类、桡足类、日本沼虾和(鱼叚)虎鱼是培育刀鲚鱼种较为适宜的饵料生物,但其不同发育阶段适宜饵料生物有所不同,摄食量与饵料的种类和数量有直接关系.     

温度、盐度和食物条件对西藏拟溞摄食强度的影响

报道了不同温度、盐度和饵料条件下西藏拟溞的摄食强度、西藏拟溞对不同饵料生物蛋白核小球藻(Chlorellapyrenoidesa)、牟氏角毛藻(Chaetoceros muelleri)、湛江等鞭金藻(Isochrysis zhanjiangensis)、亚心形扁藻(Platymonas subcordiformis)、盐藻(Dunaliella salina)、新月拟菱形藻(Nitzschiella closterium)的选择性以及摄食节律。结果表明,在适温范围(2 20℃)内,西藏拟溞的滤水率、摄食率随着温度的升高而增加,14 16℃为西藏拟溞的适宜温度。在盐度20时,西藏拟溞的摄食率最高,幼、成溞对等鞭金藻的摄食率分别为1.88 ng C/(ind.h)和3.46 ng C/(ind.h)。西藏拟溞对角毛藻的滤水率和摄食率均随着龄期增加而增加,而对等鞭金藻呈相反趋势,但二者的日粮均随体长增大而减小。幼、成溞的滤水率和摄食率随食物密度变化的趋势基本一致,均是在盐藻密度为1×106 ind./L时均最高,分别为0.194、0.221 mL/(ind.h)和0.030μgC/(ind.h)和0.034μgC/(ind.h)。幼溞对6种藻的食物选择性为角毛藻小球藻盐藻扁藻金藻拟菱形藻;成溞为扁藻角毛藻盐藻金藻小球藻拟菱形藻。幼溞、成溞均对角毛藻和盐藻的选择性较好。西藏拟溞的幼溞和成溞对牟氏角毛藻的摄食有相同的节律,在15:00 17:00和01:00 03:00时有两个摄食高峰,在09:00 11:00和23:00 01:00有两个低谷。     

黑斑原仔稚鱼藏匿行为研究

文章研究了黑斑原(Glyptosternum maculatum)仔稚鱼对缝隙的喜好行为、对底质颜色及种类的选择行为,旨在优化苗种培育模式,改善其养殖条件。结果表明:黑斑原仔稚鱼对缝隙的喜好日间(7:00—20:00)显著高于夜间(21:00—6:00; P<0.05);开口22d、23d和25—30d对缝隙无喜好行为(P>0.05),且夜间(开口6d、11—13d除外)对缝隙无喜好行为(P>0.05);开口12d、13d、15d和24d仔稚鱼表现出对较小缝隙(0.9 cm)的喜好性(P<0.05);开口2d和3d仔稚鱼表现出对底层缝隙的喜好性(P<0.05);开口5d、6d、8—21d和24d仔稚鱼表现出对表层缝隙的喜好性(P<0.05);在(400±50) lx光补偿条件下仔稚鱼对底质颜色无明显的喜好性;在(10±2) lx光补偿条件下仔稚鱼对黑色底质的喜好性显著于白色底质(P<0.05)。仔稚鱼日间具有较强的藏匿行为,喜好藏匿于较小的缝隙中,并在弱光补偿条件下喜好黑色底质。仔稚鱼的藏匿特点,为优化苗种培育和改善苗种培育环境提供了重要的...     

云斑尖塘鳢仔鱼摄食节律的研究

对自然光照条件下云斑尖塘鳢仔鱼的昼夜摄食节律和在夜间增加不同强度外光源条件下仔鱼的摄食发生率进行了研究。结果表明,云斑尖塘鳢仔鱼具有明显的昼夜摄食节律,晚上摄食发生率是著高于白天,其摄食主要集中在光线较弱的16:00～00:00;5日龄仔鱼在100～500Lx,8日龄和12日龄仔鱼在10～100Lx光照条件下的摄食发生率要明显高于黑暗或更高光照条件下的摄食发生率。     

在人工饲养条件下鲥鱼仔鱼期开口摄食的观察

受精卵孵化后的仔鱼开口摄食阶段是鱼类早期发育的关健时期,经常引起仔鱼的大量死亡,缺乏充足的适口外源性饵料可能是造成死亡的重要原因之一。1982—1983年,利用赣江产卵场人工授精的鲥鱼受精卵在室内孵化环道中孵出的仔鱼,投喂捞取的天然浮游生物饵料进行了仔鲥有关开口摄食方面的观察,其主要结果如下:仔鱼在孵化后2.5—6.5日为开口摄食期,个体全长为4.5—7.4毫米,仔鱼通常残留多少不等的卵黄物质,为混合性开食营养类型;开口摄食期间的饵料以轮虫,桡足类及其幼体(无节幼体与挠足幼体)为主要种类,适口饵料宽度为仔鱼口宽的39—81％左右,约占仔鱼全长比例的1.5—3.8％;肠内一次饵料量为平均体重的6.72％。     

燕鳐受精卵的孵化与仔幼鱼培育的初步研究

燕鳐是黄海沿岸重要鱼种之一。本文描述了燕鳐受精卵与仔幼鱼发育的形态特点和培育条件。 烟台崆蛔岛沿岸的燕鳐,5月底开始产卵,7月结束。人工受精在船上进行。受精卵和仔幼鱼在室内用静止水进行培育。 仔幼鱼的主要饵料是皱褶臂尾轮虫和卤虫幼体。幼体在室内水泥池(0.8立方米)进行培育。 受精卵和幼体在水温20.0—27.2℃,盐度31.28—31.74‰,pH8.32—8.52,溶氧(DO)1.52—8.32毫克/升的条件下进行培育。共育成幼鱼4801尾,到1981年9月20日,幼鱼最大全长92毫米。 1982年又进行了重复试验,共育出幼体6万余尾。     

Salinity tolerance of laboratory-reared larvae of the California killifish, Fundulus parvipinnis Girard

Newly hatched larvae of the California killifish ( Fundulus parvipinnis ) reared in the laboratory, were tolerant of salinities from fresh water to 70‰. Their salinity tolerance was influenced by incubation salinity; larvae hatched in lower incubation salinities exhibited greater freshwater tolerance than those hatched in higher salinities. In gradual acclimation tests, the upper median lethal salinity for the larvae was 130‰. Freshwater tolerance of the larvae decreased with age; yolk sac larvae were completely tolerant of fresh water while larvae more than 15 days old were least resistant.     

Laboratory simulation of the effects of environmental salinity on wild‐caught juveniles of European sea bass Dicentrarchus labrax and gilthead seabream Sparus aurata

Gilthead seabream Sparus aurata and European sea bass Dicentrarchus labrax , are two important species in Mediterranean aquaculture. In the wild, their juveniles occur in brackish areas such as lagoons and river deltas. Even though the juveniles seem to favour brackish environments, low salinity incurs an energy cost for osmoregulation. This paper presents the results of a series of laboratory experiments exploring the effects of salinity on growth, feeding, food conversion, survival and maintenance energy requirements of wild‐caught juveniles. The fish were kept in the laboratory, divided in groups of 20 in small tanks of 50 l each, and supplied with biologically filtered seawater of four salinity levels (8, 18, 28‰ and natural seawater) and fixed temperature (20 ± 1·4° C). The fish were fed pelleted feed throughout the experiment. Both species showed great similarity in their responses to lower salinities. Satiation time for both species increased with decreasing salinity, while maintenance requirements (required daily ration and energy) increased as with increasing salinity. Growth and feed conversion is highest for salinities around 28‰ and lower for salinities above and below. Both species share common physiological features, and intermediate salinities are optimal for their performance in nature and in captivity.     

Effects of brackish water on growth, feed conversion and energy absorption efficiency by juvenile euryhaline and freshwater stenohaline fishes

Among six species of juvenile fishes (<6 months old), stenohaline species (channel catfish Ictalurus punctatus and goldfish Carassius auratus ) had their highest specific growth rate ( G ) and most efficient food conversion ratio ( E _C) and energy absorption efficiency ( I _E) in fresh water. Three of the euryhaline species (rainbow trout Oncorhynchus mykiss , striped bass Morone saxatilis and Gulf sturgeon Acipenser oxyrinchus desotoi ) had higher G and had more efficient E _C and I _E in 3 and 9‰ salinities than in lower salinities (fresh water and 1‰). For brown trout Salmo trutta (age 3–4 months), 9‰ was above the optimum level for G and E C. However, I _E for brown trout was not significantly different at 3 and 9‰ salinities. Over the salinity range tested, channel catfish had the largest change in G , E _C and I _E, while changes for euryhaline species were relatively small. Although all species tested survived and grew in all treatments, salinities as low as 1‰ adversely affected the stenohaline species, and 9‰ adversely affected brown trout.     

Effects of salinity on the ionic balance and growth of juvenile turbot

The effects of salinity changes (27, 19 and 10‰) on seawater-adapted juvenile turbot were studied on their plasma osmolarity and ion concentrations, on oxygen consumption, on gill Na⁺,K⁺-ATPase activity after 3 months and on growth parameters. All plasma concentrations (except chloride) were unchanged, suggesting that fish were well adapted to their environment. Oxygen consumption was significantly decreased in the 19 and 10‰ groups, where fish weighed significantly more 105 days after transfer than fish maintained in sea water. These results, and the fact that apparent food conversion rates were lower in a diluted environment, suggest that on a long term schedule growth conditions could be improved by adaptation to brackish waters (salinities between 10 and 19‰). The effects of transfer from sea water to 27, 19, 10 and 5‰ were also followed during the first 3 weeks. With salinity 10‰ a steady state was reached on day 21 with all plasma values within the same range. The significant differences observed in osmolarity, plasma ion concentrations and Na⁺,K⁺-ATPase activity 3 weeks after transfer of juveniles to 5‰ salinity, compared with transfers in higher salinities, suggest that there is a threshold of acclimation of turbot to a hypotonic environment.     

Salinity effects on oxygen consumption, gill Na+, K+-ATPase and ion regulation in juvenile coho salmon

The metabolic response of juvenile coho salmon Oncorhynchus kisutch to different salinities was examined, using whole-animal oxygen consumption rates and gill Na⁺, K⁺-ATPase activities as indicators of osmoregulatory energetics. Coho salmon smolts were acclimated to fresh water (FW), isosmotic salinity (ISO, 10‰) and sea water (SW, 28‰) and were sampled for up to 6 weeks for plasma levels of cortisol, glucose and ions (Na⁺, K⁺, Cl⁻), gill Na⁺, K⁺-ATPase activity and oxygen consumption rates. Following an initial adjustment period, plasma constituents in SW fish returned to near-FW values, indicating that the fish were acclimated to SW by day 21. Gill Na⁺, K⁺-ATPase activities on days 21 and 42 were lowest in ISO, higher in FW and highest in SW. This result is consistent with the idea that less energy would be required to maintain ion balance in an isosmotic environment, where the ionic gradients between extracellular fluid and water would be minimal. Oxygen consumption rates of swimming fish (1 body length s⁻¹), however, did not differ significantly between the three test salinities after 6 weeks. The results of this study suggest that the metabolic response of juvenile salmonids to changes in salinity is dependent on life-history stage (e.g. fry v . smolt), and that oxygen consumption rates do not necessarily reflect osmoregulatory costs.     

Effects of reduced salinities on growth, food conversion efficiency and osmoregulatory status in the spotted wolffish

No significant differences in mean mass between groups were found at any time in spotted wolffish Anarhichas minor , mean (±S.D.) initial mass 76 (±21) g, reared at salinities of 12, 17, 25 and 34‰ for 12 weeks at 8° C. Salinity did not have a significant effect on daily feeding rates, total food consumption, food conversion efficiency and protein efficiency ratio. Growth trajectories varied between groups, but no overall difference in growth was found. Plasma osmolality and plasma chloride levels decreased with salinity in a 48 h abrupt exposure trial, and in the growth experiment the low salinity groups (12 and 17‰) exhibited significantly lower values compared with 25 and 34‰. The decrease was moderate and concentrations were well within the range described for other marine species. The results indicate that the spotted wolffish is a strong osmoregulator which could be reared at various salinity levels.     

Relationships between larval nutritional experience, larval growth rates, juvenile growth rates, and juvenile feeding rates in the prosobranch gastropod Crepidula fornicata

Planktonic larvae experiencing short periods of starvation or reduced food supply often grow and develop more slowly, have poor survival, fail to metamorphose, metamorphose at smaller sizes, or grow slowly as juveniles. In this study, we examined the impact of short periods of food limitation at various stages of larval development on larval and juvenile growth in Crepidula fornicata. In addition, we considered whether juveniles that were stressed as larvae grew poorly because of reduced rates of food collection due to impaired gill function. For 5 experiments, larvae were either starved for several days beginning within 12 h of hatching or were starved for the same number of days following 1 or more days of feeding at full ration (cells of the naked flagellate Isochrysis galbana, clone T-ISO, at 18×10⁴ cells ml⁻¹). In one experiment, larvae were transferred for 2 or 4 days to seawater with extremely low phytoplankton concentration (1×10⁴ cells ml⁻¹). In all experiments, larvae were returned to full ration following treatment. Control larvae were fed full ration from hatching to metamorphosis. When larvae reached shell lengths of about 900 μm they were induced to metamorphose and then reared individually at full ration in glass bowls, with phytoplankton suspension replenished daily. Larval and juvenile growth rates were determined by measuring changes in shell length (longest dimension) over time. Juvenile feeding rates were determined by monitoring changes in phytoplankton concentration over 2–3 h at the end of the growth rate determinations. In general, larval growth rates for the first 2 days after the resumption of feeding were inversely proportional to the length of time that larvae were starved. However, larval growth rates ultimately recovered to control levels in most treatments. Starving the larvae caused a significant reduction in initial juvenile growth rates (first 3–4 days post-metamorphosis) in most experiments even when larval growth rates had recovered to control levels prior to metamorphosis. Juvenile growth rates were not significantly reduced when larvae were subjected to reduced food availability (1×10⁴ cells ml⁻¹), even for treatments in which larval growth rates were compromised. Mean weight-specific filtration rates for juveniles were significantly reduced (p<0.05) following larval feeding experience in only one or possibly 2 of the 4 experiments conducted. Our data suggest that although larvae of C. fornicata may fully recover from early nutritional stress, the resulting juveniles may exhibit poor initial growth due to impaired gill function, reduced digestive capability, or reduced assimilation efficiency.     

食蚊鱼昼夜摄食节律观察

以分时段采样法研究入侵物种食蚊鱼的夏季昼夜摄食节律。食蚊鱼夏季种群内有雌鱼、雄鱼和幼鱼三个不同的摄食类群,这三个类群的摄食节律差异明显。雌鱼摄食节律成双峰型,第一高峰在10:00,而最高峰在22:00,此时肠道食物团平均重量11.70±11.60mg,饱满指数为190.22±155.61。幼鱼也成双峰型,分别在6:00和18:00有两个摄食高峰,以清晨6:00为最高,肠道食物团平均重1.08±1.09mg,饱满指数为128.44±105.49。雄鱼则成单峰型,摄食高峰出现午后14:00左右,肠道食物团平均重0.71±0.96mg,饱满指数为71.80±107.65。食蚊鱼不同摄食类群间的摄食高峰交错出现,是其协调种内关系,降低种内竞争的一种有效行为机制。     

盐度对大麻哈鱼幼鱼血液生化指标及肝组织的影响

模拟大麻哈鱼幼鱼降海洄游水域环境盐度,设0（淡水对照）、5、10、15、20共5个盐度组,以体质量（26.57±6.32）g、全长（14.44±1.05）cm幼鱼分别进行130 d饲养试验,通过血液生化指标分析及肝组织观察,研究了大麻哈鱼降海期对不同盐度适应过程的生理变化.结果表明: 血清渗透压和血清Na⁺、Cl^-变化趋势与水体盐度变化基本一致.高盐度(15、20)组血清Na⁺、Cl^-、Mg²⁺含量与低盐度(5)组和淡水组差异显著;各盐度处理组血清K⁺含量均显著低于淡水组.盐度10组的血糖浓度显著高于盐度5和20组;各盐度处理组总胆汁酸与淡水组差异显著;幼鱼血清总蛋白(TP)、白蛋白(ALB)、球蛋白(GLB)含量随盐度的升高总体呈下降趋势,其中淡水组TP和GLB含量显著高于盐度15和20组.淡水组血清谷丙转氨酶（ALT）、谷草转氨酶(AST)与高盐度组差异显著.低盐度(盐度0、5)下试验幼鱼肝细胞有部分破裂现象,肝组织空泡化严重.各组试验鱼生长和成活率无明显差异,生理生化指标显示大麻哈鱼幼鱼降海期适应盐度以10～20为宜.