多肽菌素在长牡蛎人工育苗生产中的应用

多肽菌素作为一类具有抗菌活性的生物短肽,是一种可以替代抗生素的生物肽。为了推广多肽菌素在水产养殖中的应用,本研究以长牡蛎(Crassostreagigas)人工育苗为基础,以添加2×10_(–6) mol/L青霉素钠为对照组,以添加5个不同浓度(2×10_(–6)、4×10_(–6)、6×10_(–6)、8×10_(–6)、10×10_(–6) mol/L)多肽菌素为实验组,研究多肽菌素在长牡蛎人工育苗生产中的应用。结果显示:(1)在长牡蛎种贝培育方面,培育前8天各组差异不显著(P 0.05),培育后期添加6×10_(–6) mol/L多肽菌素组存活率均最高,对照组最低,且培育至32天时该实验组均显著高于其他组(P0.05)。(2)在长牡蛎幼虫培育方面,幼虫壳高日增长量在添加6×10_(–6) mol/L多肽菌素组中最大,为11.57μm/d,而对照组仅为9.61μm/d;幼虫存活率方面对照组始终最低,而添加6×10_(–6) mol/L与8×10_(–6) mol/L多肽菌素组均保持较高存活率,显著高于对照组(P 0.05)。(3)在长牡蛎幼虫附着变态方面,添加6×10_(–6) mol/L多肽菌素组附着率最高、附着时间最短,且均与对照组差异显著(P0.05)。(4)在长牡蛎稚贝培育方面,稚贝壳长日增长量实验组均高于对照组,且随添加浓度的上升,日增长量也随之增加;稚贝存活率在添加6×10_(–6) mol/L多肽菌素组达到最高,与对照组差异显著(P0.05)。结果表明,使用多肽菌素与使用青霉素钠相比,多肽菌素显著提高了整个牡蛎培育过程中的存活率、生长速度、及附着变态率,这也为多肽菌素在贝类育苗生产中的推广提供了基础依据。     

春季珠江口水域鱼卵和仔稚鱼的分布及其与环境因子的关系

根据2004~2007年春季珠江口水域10个站位的鱼卵和仔稚鱼调查资料,着重就鱼卵和仔稚鱼的数量分布和年际变化及其与环境因子的相关关系进行研究.结果表明：其鱼卵和仔稚鱼隶属于9目33科58种（类）,以鲈形目种类数所占比例最高（为53.4%）,其次为鲱形目（为20.7%）.鱼卵和仔稚鱼大致分成半咸水性、近岸性和近海性3个生态类群.鱼卵和仔稚鱼优势种类共9种,其中鱼卵优势种为6种,仔稚鱼的也为6种.青洲附近水域是春季鱼卵和仔稚鱼的最主要分布区域之一.鱼卵和仔稚鱼数量的年际变化明显,鱼卵和仔稚鱼个体数量的最大值均出现在2006年.水温、pH值和溶解氧含量是影响鱼卵个体数量的较显著因子,盐度和溶解氧含量为影响仔稚鱼个体数量的较显著因子.盐度、pH值及溶解氧、悬浮物、叶绿素a含量对鱼卵和仔稚鱼种类数均有不同程度的影响.     

Toxic effects of several phthalate esters on the embryos and larvae of abalone Haliotis diversicolor supertexta

As the most widely used plasticizers in the world, phthalate esters (PAEs) are potential endocrine disruption compounds (EDCs). In the present study, the toxicity of dimethyl phthalate (DMP),diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP) on embryogenesis and larvae development of the marine univalve Haliotis diversicolor supertexta was examined in laboratory. The results show that the malformation of embryos appeared during the experiment, such as embryos died or lysed, small transparent flocculent rings studded on the periphery of the embryo, and the larvae could failed to hatch. In embryo toxic test, embryos incubated at the highest concentration of DMP,DEP and DBP solutions showed significantly high abnormal rate compared with the control, while DEHP solutions displayed no significant difference. In larval toxic test, in all concentrations of DMP, DEP and DBP solutions, larval settlement rates were low significantly than that of the control. Similarly, DEHP solutions show nearly no effect on the larval settlement. The order of toxicity on embryos and larvae is DBP>DEP>DMP>DEHP. Being a simple and easy stimulation to indoor spawn, sensitive to environmental factors, and short culture time, the embryos of 1-1. diversicolor supertexta can be used to indicate toxicity of the PAEs.     

Distribution of whitemouth croaker (Micropogonias furnieri, Desmarest 1823) larvae in the Río de la Plata estuarine front

Whitemouth croaker (Micropogonias furnieri) larvae obtained and hydrographic data collected in the Rio de la Plata estuary (35°S–56°W) between 1987 and 2000 were used to explore the early life stages spatial and temporal distribution patterns and their relation to oceanographic features. The spatial distribution, restricted to a band in the inner part of the estuary, coincided with the bottom salinity front and the maximum turbidity zone (MTZ, turbidity front). Larvae were present during the warmest months (October through May) within a range of 14–24.5 °C temperature and 0.9–33 salinity. A vertically stratified sampling performed in the region where the largest abundance was found (December 2005 and March 2006) was used to test the hypothesis that larvae retention occurs in the bottom salinity front.The vertically stratified sampling showed larvae throughout the water column with high predominance in the river–estuary transition zone. A positive correlation between abundance and the bottom salinity horizontal gradient was found. The size analysis showed that the largest individuals (>10 mm SL), probably undergoing the settlement process, inhabited near the bottom and that the smallest (<10 mm SL) were present in the whole water column. Length distribution along the front showed no trend.Results support the estuarine retention hypothesis of previous studies on whitemouth croaker gravid females, eggs distribution and outcomes from a numerical simulation model. Retention in the salinity front/MTZ would allow larvae to benefit from food accumulation in the region, the high turbidity level provide shelter against predators and retention in the estuary secure closeness to the main nursery ground.     

饥饿对日本囊对虾幼体发育、摄食及存活的影响

本实验研究了饥饿对日本囊对虾蚤状幼体Ⅰ期发育、摄食及存活的影响。结果表明．饥饿对对虾幼体的变态存活有显著影响，饥饿时间与变态率及变态时间呈线性关系．饥饿对日本囊对虾幼体首次摄食影响显著。本实验中，日本囊对虾的蚤Ⅰ幼体的PNR100应为40h。     

长江口及其邻近水域鱼卵、仔鱼的种项组成与分布特征

鱼卵、仔鱼作为海洋生物的被捕食者、捕食者,不仅种类多,而且数量大,常是研究海洋生态系统重要的组成部分.通过对鱼卵、仔鱼的调查研究,可了解和掌握鱼类产卵场和产卵期,确定中心渔场的位置和寻找产卵鱼群,鱼卵仔鱼尚决定着资源的补充,从而为资源量的估算提供理论基础.     

大西洋浪蛤(Spisulasolidissima)人工繁殖 初步试验

1999年5～6月对大西洋浪蛤进行人工繁殖试 验。结果表明,大西洋浪蛤一年能达到性成熟,一个繁殖季节产卵一次,卵为球形,卵径为 50～60μm;在23℃左右水温下,受精卵经16～20h发育成D形幼虫,幼虫浮游期为16～20d; 壳长260～290μm时为附着变态阶段。幼虫培育盐度要求在16以上。     

冠瘤海鞘同种群聚的化学诱因初步研究

研究了不同浓度的冠瘤海鞘成体被囊萃取物和幼体萃取物及不同的幼体密度对冠瘤海鞘(Styela canopus)幼体附着和变态的影响.结果表明,冠瘤海鞘被囊萃取物和幼体萃取物在5%和10%的浓度下均促进冠瘤海鞘幼体的附着和变态,但被囊萃取物的诱导效果明显强于幼体萃取物;幼体密度高于25只/cm3时,促进冠瘤海鞘幼体的附着和变态;幼体密度低于10只/cm3时,幼体的附着和变态不受密度影响.这些结果提示海区中冠瘤海鞘的同种群聚可能与其被囊或幼体内含诱导幼体附着和变态的化学因子有关.     

金钱鱼早期发育的观察

金钱鱼Scatophagus argus是一种具有观赏和食用价值的重要海水经济鱼类。文章对金钱鱼受精卵的胚胎发育过程和胚后不同发育阶段的形态特征进行了观察和描述,并对其仔、稚鱼饵料摄食情况作了初步观测。结果显示,在海水温度27.0~28.5℃、盐度26‰、pH为8.10~8.25的条件下,金钱鱼受精卵历时21h 30min完成整个胚胎发育过程孵化出膜。刚破膜仔鱼全长1.60±0.04mm,4h后全长1.79±0.04mm;卵黄囊椭圆球形,长径0.63±0.03mm,短径0.38±0.02mm。在水温28.0~29.0℃、盐度22‰~26‰海水中,1日龄仔鱼全长2.23±0.05mm,体高0.47±0.02mm,卵黄囊明显吸收;5日龄仔鱼全长2.85±0.07mm,卵黄囊和油球吸收完毕,仔鱼口裂0.17~0.18mm,开始摄取粒径0.10~0.12mm的轮虫幼体;9日龄仔鱼全长3.25±0.04mm,腹鳍鳍棘原基形成,胃肠充满饵料食物,消化吸收能力增强,仔鱼群体完全进入异养生长阶段;15日龄仔鱼全长3.72±0.03mm,腹鳍伸展,出现一对雏形鳍棘,仔鱼活力极强,可轻易摄食0.12~0.18mm的轮虫和桡足类幼体;32日龄的稚鱼尾部细小黑色素粒密集,体侧出现4条褐色横纹,背鳍、臀鳍和腹鳍鳍棘及鳍条基本发育完整,颅骨后下方两侧长出一对三叶状特异形骨结节突起,口裂约0.50mm,主食桡足类和硅藻,并能够摄食少量软性配合饲料。本研究可为金钱鱼繁育生产和早期形态鉴别提供生物学依据。