SWELLING OF FISH MITOCHONDRIA

The physical properties of fish liver and rat liver mitochondria were compared as a function of temperature and osmotic pressure. The data indicate that fish mitochondria are more flexible and swell at a more rapid rate over a 0 to 30°C temperature range, whereas the rates of swelling at 30 to 40°C are comparable. The swelling rates of both fish and rat mitochondria vary with temperature and approximate the Arrhenius relationship. Apparent energies of activation for swelling averaged 26.5 kcal and 12.9 kcal for rat and fish, respectively. Fish mitochondria were less stable than rat mitochondria to osmotic variation, and the disparity in initial swelling rates became increasingly greater with lower osmotic pressure. The hypotonic swelling of both fish and rat mitochondria was readily reversed osmotically; however, there was a very rapid decay of reversal in fish mitochondria and only a very slow decay in the case of rat. All the data indicate that under comparable conditions the fish mitochondrial membranes are more flexible and presumably more permeable and labile than rat mitochondrial membranes. The findings are discussed in relation to the general metabolic implications and the possible contributions of the membrane constituents to membrane behavior.     

配养滤食性鱼对投饵网箱养鱼负荷力的影响

本文用现场围隔实验的方法研究了养鱼水库中配养鲢对投饵网箱养鲤负荷力的影响。共用围隔30个,每个围隔水深5m,容积14.3m~3。实验中观测了理化指标8项、生物指标5项。实验结果表明配养鲢不仅在溶氧(DO)、化学需氧量(COD),总磷(TP)等方面明显改善了水质,而且还降低了浮游植物、浮游动物和浮游细菌的数量。配养鲢对投饵网箱养鲤的净产量,生长率,饲料效率都有显著地提高;使鲤、鲢的总负荷力和总鱼产量各自都提高了35％。并已查明,投饵网箱养鲤与水库配养鲢的适宜现存量比例3:1优于2:1。     

FISH AND FISHERIES OF WETLANDS

SUMMARY

The three major wetland types have characteristic fish communities. River-associated wetlands harbour a rich diversity of fishes which can either survive habitat desiccation during the dry-down, or migrate to and fro with the flood. Endorheic wetlands have a lower diversity of species which are typically ‘r’-selected relative to mainstream riverine or lacustrine forms. Marine wetlands have a variety of peripheral or marine forms, but are not discussed in this account. The dynamics of wetland fish communities are determined by periodically changing abiotic factors, especially water temperature and water level, and biotic factors, especially food availability. Water level fluctuations have several important functions and result in pulses of nutrient input and fish abundance. Wetland fish stocks can usually be sustained as long as the pristine flood regime is retained, but disruption of the flooding pattern interferes with fish breeding and nutrient flow. Fishing yields may be directly correlated with the flood history during the previous two years. Wetland fishes play an important role by converting the resource at the base of the food chain, i.e. living plants, detritus or epiphytes, into food for higher trophic levels. The need to identify and conserve key food supplies is emphasized. Wetland fisheries are relatively poorly developed in southern Africa with notable exceptions, e.g. Pongolo floodplain, Okavango swamp, Lake Liambezi, Elephant Marsh on the Shire River, but even in these systems the resource is probably underutilized.

The need to consider the socio-economic implications of upgrading a subsistence fishery are emphasized, and further study on the effect of water level fluctuations on major trophic pathways and on multispecies fisheries is encouraged. Because of the urgent need to manage wetland fisheries, various short-cut methods to obtain first-order estimates of fish production, yields and growth rates should be used until more data are available. The need to manage a floodplain holistically for both the aquatic and terrestrial phases is stressed. In addition, inocula (re-colonizing life history stages) should be conserved to accelerate the recovery of endorheic wetland fish stocks after a drought. As wetlands are of fundamental importance to lake or river metabolism and provide vital breeding and feeding areas for fishes, they should be given the highest conservation priority. Cost-benefit analyses should therefore be performed before any large scale manipulations of wetlands are performed.     

鱼类多样性的遗传基础

鱼类的多样性正伴随着地球的生物多样性危机而日益受到关注。对鱼类多样性的阐释也成为研究中的热点之一。“机会垂青于有所准备的基因组”。目前的研究表明,基因组的可塑性（ｐｌａｓｔｉｃｉｔｙ）成为物种分化、形态演化以及适应环境改变等的遗传基础。本文侧重于染色体水平,即鱼类染色体数目变化极大、染色体倍型多态、鱼类性别决定系统的多态和超数染色体（Ｂ染色体）的存在提示鱼类基因组的可塑性很强;同时鱼类在基因组中存     

鱼类饲料的污染物

饲料源包括牧草干草料、青绿饲料、青贮饲料、能量饲料、蛋白质饲料、维生素添加剂、矿物质添加剂,还有药物、色素、激素、粘结等添加剂,其中除了矿物质和粘结添加剂的膨润土外,都是有机物。       

鱼类细胞因子研究进展

免疫系统是指机体识别和消除异物的防卫系统,主要功能是防御和维护机体自身稳定。鱼类免疫系统包括细胞免疫和体液免疫;细胞因子(Cytokine)是其中重要的组成部分。细胞因子是一类由免疫细胞和非特异性免疫细胞合成或分泌的小分子多肽物质,具有调节多种细胞生理功能的作用。在一般状况下,细胞因子的分泌量很低,或处于失活状态;但在机体的免疫细胞或组织受到刺激发生新的基因转录后,其含量将会大幅度上升,并识别细胞上高亲和性的表面受体,以协同形式结合其他的细胞因子或者抗病毒分子发挥生物学效应,发挥免疫调节作用。       

哈拉哈河上游的鱼类区系和资源现状

哈拉哈河上游的鱼类采集到１４种和亚种,分水于４目６科,其中鲤科８种,占５７．１％。区系组成分归５个区系类群,其中属于全北区的北方山地,北方平原和北极淡水类群鱼类有１０种,占７１．４％,这与该河系具有适于冷水性鱼类栖存的生态条件密切相关。     

鱼类早期生活史阶段的自然死亡

阐明鱼类早期大量死亡的机制,不仅在理论上具有重大意义,而且在实践上将给整个人类社会带来巨大的经济效益。因此,围绕着鱼类早期死亡而展开的经济鱼类补充量变动的研究,一直是本世纪鱼类早期生活史川研究领域和渔业生态学研究的中心论题。同时,研究鱼类早期自然死亡,对于推动我国野生鱼类资源的保护和持续利用这一最新研究 领域的发展,亦将起重要的作用。然而,由于卵和仔鱼自然死亡的原因和程度的实录证据,目前还很少获得(原因是卵和仔鱼死后很快分解,网具采样所获大都是活体);因此,定量分析鱼类早期自然死亡还有很大困难。但是,现已提出的一些现象、假说、观点、理论和研究方法,为探索这一难题,提供了重要途径。       

氦氖激光对鱼类生长的影响

本试验采用氦氖激光(632.8nm)以不同的功率和不同功率密度,或者不同的辐照方式,辐照孔雀幼鱼(Poecilia reticulata)、尼罗罗非鱼(Oreochromis niloticus)和淡水白鲳(Ephippus orbis)。实验结果表明,He-Ne激光辐照对三种幼鱼的生长均有促进的作用,并且不同的功率和功率密度的影响是不同的,适当的激光参量会产生较佳的影响效果。     

水库对投饵网箱养鱼的负荷力

本文用１８个１４．３ｍ￣３的围隔组成的围隔群,以鲤为材料,研究了水库对投饵网箱养鱼的负荷力。实验中观测了水温、透明度、ｐＨ值、溶氧、化学耗氧量、生化需氧量与非离子氨等环境因素的变化。结束时将这些变化与我国渔业水质标准相比较,查明该负荷力约为３０００ｋｇ·ｈａ￣（－１）,建议增加２５－３５％的安全储备,以最大载鱼量１８００－２３００ｋｇ·ｈａ￣（－１）作为推荐值。     

菱湖鱼病工作站:现代科学改造中国传统养鱼业的序曲

1953年,为帮助菱湖鱼农解决鱼病问题,中国科学院水生生物研究所在浙江省吴兴县菱湖镇建立了中国第一个鱼病工作站。自1953年5月成立至1956年3月撤离菱湖的近3年间,以倪达书为站长的菱湖鱼病工作站科研人员以四大家鱼为主要对象,在菱湖及周边养鱼区开展了鱼病病原调查、防治试验和门诊,在病原的分类鉴定和有效杀灭药物的筛选等方面取得了较大进展,对十几种流行广、危害大的主要鱼病,结合群众养鱼经验并通过试验研究,找到了有一定疗效的药物和治疗方法,总结出一套比较完整的防病养鱼措施并向全国推广,改变了当地鱼农"鱼病不能治"的保守观念,同时还为浙江省和全国各地鱼区培养了大批鱼病防治干部。菱湖鱼病工作站确立了中国鱼病防治的良好传统,开创了中国的鱼病学科,奠定了中国鱼病学基础,并为国内培养了众多鱼病防治人才,可谓现代科学改造中国传统养鱼业的序曲。