上海地区樟树红蜡蚧生活习性的初步观察

红蜡蚧在上海地区年发生1代,以受精雌成虫越冬。孕卵量于5月底、6月初达到高峰,孵化高峰于6月中旬。雌、雄成虫于8月中旬陆续羽化。在室外喷雾40倍花保、80倍花保、2000倍30％C酰甲胺磷、3000倍30％乙酰甲胺磷和2000倍25％灭幼脲三号,7d后的校正死亡率分别在89．00％和100％。     

基于碳、氮稳定同位素技术的大亚湾紫海胆食性分析

为掌握大亚湾紫海胆(Heliocidaris crassispina)的食性特征,应用碳、氮稳定同位素技术对2015年8月所采集紫海胆样本的稳定同位素特征、营养级和食性特征进行了初步研究。结果表明,大亚湾紫海胆平均δ~(13)C值为-(13.35±1.21)‰,平均δ~(15)N值为(9.14±0.38)‰,平均营养级为2.11±0.14。不同壳径紫海胆之间的碳、氮稳定同位素比值无显著性差异(P0.05)。大亚湾海域紫海胆生活环境周围生物δ~(13)C值分布范围为-20.76‰~-9.93‰,δ~(15)N值分布范围为-0.16‰~14.99‰,营养级范围为1.34~3.77。大亚湾主要生物种类可划分为悬浮物、初级生产者和初级消费者、次级消费者、顶级消费者4个营养组群,其中紫海胆属于次级消费者。8月份调查海域珊瑚稀少,大型海藻密度低且死亡降解形成颗粒有机物(Particulate Organic Matter,POM),陆源POM随降雨大量流入大亚湾,导致紫海胆在8月份摄食偏向碎屑食物链,主要食物来源为POM,平均贡献率为67.3%;其余摄食种类为沉积物(Sediment Organic Matter,SOM)、裂叶马尾藻(Scagassum siliquastrum)、底栖硅藻、浮游动物及浮游植物,平均贡献率分别为9.7%、9.3%、6.7%、3.7%及3.3%。大亚湾紫海胆摄食种类与其栖息地底栖生物存在重叠,具有一定的食物竞争关系。研究表明,分析紫海胆食性特征对了解其所在生态系统中营养级水平具有重要意义。     

池养条件下革胡子鲶仔幼鱼摄食习性与生长的初步研究

本文报道了在人工饲养条件下革胡子鲶仔幼鱼的摄食习性和生长的研究结果。仔鱼孵出2或3日,尚残存卵黄囊时即行开口摄食。仔鱼适口的开食饵料是轮虫,随着鱼体的生长,摄食枝角类、桡足类和摇蚊幼虫的比例迅速增加。幼鱼昼夜摄食强度有一定的节律,夜间18:00～22:00时摄食强度最大。经测量和数理统计分析,确定革胡子鲶仔幼鱼的全长与日龄呈直线关系,体重与日龄和全长对体重的关系均为幂函数关系,并计算出它们相应的回归方程式。     

贵阳红枫湖鲢、鳙的食性研究

鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis)是滤食性鱼类,具有净化水体的作用。从2007年开始,贵阳市每年向红枫湖投放500万鲢、鳙进行水体富营养化的治理。为了分析红枫湖鲢、鳙对饵料资源的利用情况,在2010年10-11月研究了鲢、鳙的摄食强度,在2011年5-6月研究了鲢、鳙的摄食强度、食物组成及比例等方面。结果表明:鲢、鳙的总摄食率分别为98.00%、96.93%;冬季鲢、鳙的饱满指数范围分别为44.13～99.79%、46.12～127.00%,春季鲢、鳙的饱满指数范围为53.27～245.14%、49.94～234.32%,鲢、鳙春季的饱满指数显著高于冬季。在食物组成上,鲢的肠道有36种藻类,鳙的肠道有31种藻类。从个数比例来看,鲢、鳙食物中浮游植物占个数组成比例的99%以上,浮游动物很少;但从重量比例来看,浮游动物在鲢、鳙体内分别占(50.993±2.214)%、(90.799±2.321)%。选择性指数E表明鲢对蓝藻门的浮游植物有较大的选择性。     

Diet and fish choice of Eurasian otters (<Emphasis Type="Italic">Lutra lutra</Emphasis> L.) in fish wintering ponds in Hungary

The diet composition and fish preference of piscivorous Eurasian otters (Lutra lutra) were studied in two fish farm systems in Hungary using spraint (otter faeces) analysis during two wintering periods. The primary food source of otters in both fish farms was fish (97–99% of biomass). The main fish prey was small-sized, below 100 g in weight (96% in both areas), while fish prey above 500 g comprised only 0.1–0.4% of the diet. The bulk of the otters’ diet consisted of less-valued species, especially non-native Prussian carp (Carassius auratus gibelio). Consumption of commercial fish species ranged between 15 and 31% of the total diet. Otters preferred fish below 100 g in weight (Ivlev’s electivity index, E _i = 0.65–0.70), and showed a lesser preference for (or avoided) fish above 100 g in weight (E _i = −0.37–1.00). With regard to species distribution, otters preferred small (below 100 g) grass carp (Ctenopharyngodon idella), zander (Sander lucioperca), pike (Esox lucius), Prussian carp, topmouth gudgeon (Pseudorasbora parva), while they consumed common carp (Cyprinus carpio), the most important commercial species, proportionally to its abundance in the environment (E _i = −0.18–0.29).     

光裸方格星虫繁殖习性的初步观察

2011年6、7、8月每月10日,挑选♀∶♂为5∶1的性成熟光裸方格星虫(Sipunculus nudus)亲体,在水泥池中暂养20 d,观察其产卵习性、产卵量及其体腔中生殖细胞的变化。结果表明,光裸方格星虫雌雄异体、体外受精;卵母细胞分批成熟,分批产卵;产卵时间不固定,昼夜皆可产卵,但夜间产卵次数和产卵量均高于白天;大量产卵时集群游动;6、7、8月的雌光裸方格星虫平均产卵分别为:3.20×104、4.43×104、3.46×104cell,平均受精率达98.3%;6、7、8月日累计产卵量y与时间x的变化方程分别为:y=0.430 5x3-25.971x2+503.39x-582.56(R2=0.982 0)、y=0.583 3x3-33.942x2+659.04x-712.43(R2=0.984 7)、y=-0.31x3+1.4676x2+245.11x-278.22(R2=0.994 3)。6、7、8月成熟卵细胞相对百分含量分别降低4.8%、9.0%、26.0%(P<0.01);6、7月的光裸方格星虫产后具有较好的再繁殖能力。     

一种资源保护型蟹笼的初步试验

任何新渔具渔法的开发，必须同时考虑到资源保护。针对笼捕梭子蟹作业开发和推广过程中出现的蟹笼网目较小、幼蟹渔获率高等弊病，在梭子蟹入笼机制、行为习性观察基础上设计制作了资源保护（幼蟹释放）型蟹笼，并进行多次试验。结果认为，蟹笼似选择安装每只直径８ｃｍ的幼蟹释放孔装置方式，达到保护梭子蟹资源目的。     

Metabolic scope, swimming performance and the effects of hypoxia in the mulloway, Argyrosomus japonicus (Pisces: Sciaenidae)

The culture of the mulloway (Argyrosomus japonicus), like many other Sciaenidae fishes, is rapidly growing. However there is no information on their metabolic physiology. In this study, the effects of various hypoxia levels on the swimming performance and metabolic scope of juvenile mulloway (0.34 ± 0.01 kg, mean ± SE, n = 30) was investigated (water temperature = 22 °C). In normoxic conditions (dissolved oxygen = 6.85 mg l^− 1), mulloway oxygen consumption rate (M·o₂) increased exponentially with swimming speed to a maximum velocity (U_crit) of 1.7 ± < 0.1 body lengths s^− 1 (BL s^− 1) (n = 6). Mulloway standard metabolic rate (SMR) was typical for non-tuna fishes (73 ± 8 mg kg^− 1 h^− 1) and they had a moderate scope for aerobic metabolism (5 times the SMR). Mulloway minimum gross cost of transport (GCOT_min, 0.14 ± 0.01 mg kg^− 1 m^− 1) and optimum swimming velocity (U_opt, 1.3 ± 0.2 BL s^− 1) were comparable to many other body and caudal fin swimming fish species. Energy expenditure was minimum when swimming between 0.3 and 0.5 BL s^− 1. The critical dissolved oxygen level was 1.80 mg l^− 1 for mulloway swimming at 0.9 BL s^− 1. This reveals that mulloway are well adapted to hypoxia, which is probably adaptive from their natural early life history within estuaries. In all levels of hypoxia (75% saturation = 5.23, 50% = 3.64, and 25% = 1 .86 mg l^− 1), M·o₂ increased linearly with swimming speed and active metabolic rate (AMR) was reduced (218 ± 17, 202 ± 14 and 175 ± 10 mg kg^− 1 h^− 1 for 75%, 50% and 25% saturation respectively). However, U_crit was only reduced at 50% and 25% saturation (1.4 ± < 0.1 and 1.4 ± < 0.1 BL s^− 1 respectively). This demonstrates that although the metabolic capacity of mulloway is reduced in mild hypoxia (75% saturation) they are able to compensate to maintain swimming performance. GCOT_min (0.09 ± 0.01 mg kg^− 1 m^− 1) and U_opt (0.8 ± 0.1 BL s^− 1) were significantly reduced at 25% dissolved oxygen saturation. As mulloway metabolic scope was significantly reduced at all hypoxia levels, it suggests that even mild hypoxia may reduce growth productivity.     

东海中北部小眼绿鳍鱼食性的季节变化

根据2008年5月~2009年2月收集到的小眼绿鳍鱼胃含物样品,对其摄食习性的季节变化进行了研究。结果表明,小眼绿鳍鱼全年摄食的饵料种类数共有93种,磷虾类、长尾类和鱼类为其主要饵料类群。其食物组成存在季节差异,春季小眼绿鳍鱼以太平洋磷虾、脊腹褐虾和鳀鱼为主要食物;夏季以细巧仿对虾、脊腹褐虾、口虾姑和葛氏长臂虾为主要食物;秋季以太平洋磷虾、戴氏赤虾、细螯虾和鳀鱼为主要食物;冬季以鳀鱼、细螯虾、褐菖鲉和对虾为主要食物。摄食强度的季节变化呈显著差异(P0.05),春季最高,夏季最低;各个季节的主要饵料类群组成存在差异,但长尾类和鱼类在四个季节都有分布。通过与历史资料进行比较发现,东海小眼绿鳍鱼的食物组成与饵料生物的季节变化息息相关。     

Effects of soft-water acclimation on the physiology, swimming performance, and cardiac parameters of the rainbow trout, Oncorhynchus mykiss

Rainbow trout acclimated to soft water were submitted to an incremental velocity trial, and exhibited a 14% decrease in critical swimming speed (U _crit ∼ 1.37 ± 0.055 vs. 1.54 ± 0.044 m s⁻¹) compared to fish kept in hard water. After a standardized swimming protocol, soft-water-acclimated fish had higher blood lactate concentrations (6.5 ± 0.66 and 6.0 ± 0.64 mmol L⁻¹ (soft water) vs. 5.0 ± 0.46 and 3.9 ± 0.32 mmol L⁻¹ (hard water)), revealing a greater use of anaerobic metabolism for the same exercise. Cardiovascular parameters were investigated while fish were swimming at increasing water velocities, revealing that soft-water-acclimated fish had lower increases in heart rate (105% vs. 118% of pre-exercise values), due to higher heart rates observed during acclimation and during the first 10 min of the swimming trial. This was also reflected by the plateau in heart rate and stroke volume observed during the swimming protocol, which can be attributed to increased cardiovascular function in response to soft-water acclimation. These results are in accord with previously reported increases in blood-to-water diffusion distance, due to proliferation of chloride cells at the gills in response to soft-water conditions, and underscore the costs and limitations of soft-water acclimation. R. C. Playle—Deceased.