鱼类早期发育阶段摄食行为研究现状

对鱼类早期阶段的摄食行为研究进行了综述。重点阐述了胃含物分析法、饥饿对摄食的影响、摄食器官的形态发育特征与摄食行为的关系、食物选择及其生理生态因子对摄食的作用。初步探讨了仔稚鱼饥饿后的捕食量和捕食速度的变化,并结合食物保障,分析了食物选择性指数I在鱼类摄食行为研究中的应用。     

Hypoxia-based habitat compression of tropical pelagic fishes

Large areas of cold hypoxic water occur as distinct strata in the eastern tropical Pacific (ETP) and Atlantic oceans as a result of high productivity initiated by intense nutrient upwelling. We show that this stratum restricts the depth distribution of tropical pelagic marlins, sailfish, and tunas by compressing the acceptable physical habitat into a narrow surface layer. This layer extends downward to a variable boundary defined by a shallow thermocline, often at 25 m, above a barrier of cold hypoxic water. The depth distributions of marlin and sailfish monitored with electronic tags and average dissolved oxygen (DO) and temperature profiles show that this cold hypoxic environment constitutes a lower habitat boundary in the ETP, but not in the western North Atlantic (WNA), where DO is not limiting. Eastern Pacific and eastern Atlantic sailfish are larger than those in WNA, where the hypoxic zone is much deeper or absent. Larger sizes may reflect enhanced foraging opportunities afforded by the closer proximity of predator and prey in compressed habitat, as well as by the higher productivity. The shallow band of acceptable habitat restricts these fishes to a very narrow surface layer and makes them more vulnerable to over‐exploitation by surface gears. Predictably, the long‐term landings of tropical pelagic tunas from areas of habitat compression have been far greater than in surrounding areas. Many tropical pelagic species in the Atlantic Ocean are currently either fully exploited or overfished and their future status could be quite sensitive to increased fishing pressures, particularly in areas of habitat compression.     

鲁烟Ⅰ号防治主要蚕病技术的研究

为取代治疗真菌病防僵药物、治疗细菌病抗生素类药物及防治蚕病,笔者研制了蚕业消毒新药——鲁烟Ⅰ号。经中试,鲁烟Ⅰ号对家蚕病毒、真菌、细菌等主要蚕病的病源具有很好的杀灭效果,用鲁烟Ⅰ号作为防治主要蚕病的药物,取代了传统养蚕中的多种药物,用药方便,取得了良好的效果。     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.     

Nearshore fish assemblages associated with introduced predatory fishes in lakes

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22种海水鱼中ACEI的制备及其化学修饰

以取自中国黄海的22种鱼类为研究对象，测定其鱼肉组织上清液的酶解物对血管紧张素转化酶（ACE）的抑制作用。从6种商业用酶和1种新型海洋低温碱性蛋白酶（MLAP）中，筛选出MLAP作为酶解制备ACEI的理想水解酶。以该酶水解上述22种海水鱼鱼肉组织上清液，并将水解液经Sephadex G-25凝胶层析和DEAE Sepharose阴离子交换层析，得到ACEI纯品。测定各类ACEI体外抑制ACE的活性发现，这22种海水鱼中以缇鱼（Engraulis japonicus）所产ACEI活性最高，其余鱼类无显著差异。以缇鱼制备血管紧张素转化酶抑制剂（ACEI-22），并对ACEI-22作进一步研究，结果发现，ACEI-22对自发性高血压大鼠（SHR）有降压效果，但不显著；ACEI-22经聚乙二醇化学修饰后，修饰率为68％，且给药SHR后，大鼠收缩压显著降低，与相同条件下同剂量的卡托普利的降压效果相当。故聚乙二醇修饰的ACEI-22可有效地降低SHR的血压。     

Social learning in fishes: a review

Animals acquire skills and knowledge from other animals, and fish are no exception. There is now strong experimental evidence that many species of fish exhibit social learning and traditional behaviours. Here, we review the literature pertaining to social learning in fish, focusing on (i) antipredator behaviour, (ii) migration and orientation, (iii) foraging, (iv) mate choice and (v) eavesdropping.     

Persistence of native fishes in small streams of the urbanized San Francisco Estuary,California: acknowledging the role of urban streams in native fish conservation

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软包装即食醉鱼制品细菌学品质安全分析

对上海市场常见品牌的软包装即食醉鱼制品感官、理化、细菌学品质状况进行定性和定量研究,并对潜在病原菌安全性进行评价。结果表明,产品水分含量、水分活度、pH和盐分含量分别为43.50%~56.97%,0.93~0.97,6.07~6.73,2.41%~6.63%,差别较大;细菌菌落总数、耐热菌落总数分别是1.8×102~4.2×105cfu/g,38~3 800 cfu/g;厌氧菌落总数和金黄色葡萄球菌均低于10 cfu/g。由细菌总数计数平板分离256株细菌,鉴定残存主要细菌菌群为芽孢杆菌(34.0%)、葡萄球菌(27.3%)、玫瑰小球菌(14.0%),并出现少量的棒状杆菌(5.5%),表明热杀菌强度不足。产品中残存有一定数量的蜡样芽孢杆菌,对其潜在危害有待进一步研究。     

前氮后移对杂交中稻及其再生稻产量的影响

以20个杂交中稻组合为材料,在前氮后移与重底早追两种施氮方式下,研究了前氮后移对头季稻及再生稻产量的影响。结果表明,前氮后移有助于提高杂交中稻组合头季稻及再生稻产量,且高于重底早追施氮方式,但各杂交组合间表现各异。其中,内5优306、蓉18优447、德香4103、内5优317和川谷优7329这5个组合前氮后移处理头季稻比重底早追处理显著或极显著增产,乐优198、宜香优800、蓉优1808、冈比优99、冈优725、德香4103、炳优900、F优498、内5优317这9个组合的再生稻产量前氮后移处理比重底早追处理高。综合考虑头季稻产量和再生力,两季总产较高的组合为宜香优800、内5优317和蓉18优447。