四种重金属离子对侧扁软柳珊瑚的毒性及其摄食行为的影响

本实验通过48h的急性毒性测试,来了解重金属Cu2 、Zn2 、Cd2 、Pb2 的污染环境对侧扁软柳珊瑚(Subergorgiasuberosa)的影响程度,以认知重金属对海洋生物尤其是柳珊瑚所造成的伤害.实验的结果显示,Cu2 的半致死浓度约为0.13mg/dm3,Zn2 为8.69mg/dm3,而Cd2 为10.84mg/dm3,Pb2 为8.49mg/dm3;亦即Cu2 污染对侧扁软柳珊瑚毒性影响最大.另外,在实验的观察中也发现,受到伤害的珊瑚中常会刺激黏液的分泌,在较高的浓度下则会造成其共肉组织的溃烂致使整株珊瑚部分或整体的死亡.在摄食影响的研究方面,侧扁软柳珊瑚在Cu2 浓度分别为0.02、0.05mg/dm3的污染环境下捕食丰年虫(Chirocephalus)的行为与正常珊瑚间有明显差异(p<0.01),经过Cu2 污染环境后的珊瑚虫(polyp)常常不能有效地捕食到丰年虫,甚至捕食到丰年虫却不能将其顺利吞咽而造成丰年虫从其触手中逃逸.数据显示正常珊瑚虫捕食丰年虫的成功率平均达85.42%,而受0.02mg/dm3Cu2 影响的珊瑚虫则为57.58%,受0.05mg/dm3Cu2 影响的则仅为24.24%.     

Size Selective Predation by the Asteroid Pisaster ochraceus on the Bivalve Mytilus calif ornianus: A Cost-Benefit Analysis

Abstract. When simultaneously presented with equal numbers of four sizes of clumped Mytilus californianus (20, 35, 55 and 85 mm shell length), Pisaster ochraceus (arm length of 70-110mm R) showed a preference for the medium sizes (35 and 55mm length). Prey-size preference was positively correlated with predator size. Mean prey-digestion times (insertion of the stomach, opening of the valves and digestive period) decreased significantly following fiiing of an artificial gape between the valves of mussels. When presented with different sizes of clumped filed mussels, starfish still chose medium mussels, indicating that stomach insertion, valve opening, and digestion rate may not be important constraints determining size selective predation. Measurements of the force required to dislodge mussels from the substratum and conspecifics showed an increasing exponential relationship with mussel size. Size selective feeding may be an energy maximizing and time minimizing strategy, where energy gained from choosing larger mussels is balanced against disproportionately increased costs in energy and time of removing large mussels from the substratum.     

Diel vertical migration of Euphausia pacifica (crustacea, euphausiacea) in relation to molt and reproductive processes, and feeding activity

We investigated the diel vertical migration of Euphausia pacifica in relation to molt and reproductive processes and feeding activity in April and September 2001 at fixed stations off northeastern Japan. The vertical distribution of this species was shallower in April than in September during both day and night, which was partly explained by a high surface temperature (19°C) and the existence of a subsurface chlorophyll maximum in September. It has been demonstrated for the first time that diel vertical migration of this species is influenced by molt processes because upward migration of molting individuals was restricted compared with non-molting ones. Feeding activity of molting individuals was reduced throughout the day, being lower than or similar to the daytime feeding activity of non-molting ones. The percentage of molting individuals was least (2–4%) among the gravid females, which suggests that gravid females molt less frequently than other stages of females and males. Molt and reproductive processes therefore seemed to be coupled in this species.     

摄食对锯缘青蟹溞状幼体生长和呼吸的影响

本文采用实验室和现场测定相结合的方法，研究了锯缘青蟹溞状幼体摄食率、摄食和饥饿对幼体生长发育蜕皮以及呼吸的影响.实验结果表明锯缘青蟹第一期溞状幼体(Z     

养殖条件下暗纹东方鲀摄食与食性的初步分析

本文报道了养殖条件下暗纹东方Tun的摄食行为和不同生长阶段食物组成的变化，肠道食物分析表明，除主食配合饲料外，同时也摄食一些天然饵料（底栖类及小杂鱼等）。其肠长与体长呈直线相关，回归方程为Y．2.85x-32.36(X为体长，Y为肠长，单位：mm，相关系数R^2=0.9987),肠长为体长的2.35-2.74倍。同时对其食性的相关问题进行了讨论。     

2000年秋季黄、东海典型海区叶绿素a的时空分布及其粒径组成特征

分析了 2 0 0 0年秋季黄、东海几个典型海区的叶绿素 a调查资料 ,结果表明 :在没有温跃层存在的海区 ,叶绿素 a的垂直分布是均匀的 ,昼夜 (2 4 h)变化的幅度也很小 ,且上、下层不同粒径的浮游植物所含叶绿素 a的比例变化也不大。但在明显存在温跃层的海区中 ,叶绿素 a的垂直变化明显 ,昼夜变化的幅度较大 ,且在温跃层的上、下方显示相反的变化规律 ;不同粒径浮游植物叶绿素 a的比例组成在温跃层上、下方明显不同 ,在温跃层的下方 ,较大粒径 (2～ 2 0μm,>2 0μm)的叶绿素 a所占的比例明显大于其在表层水中所占的比例     

水产饲料企业信息化的若干问题

在滚滚而来的信息革命浪潮中，水产饲料企业应当如何面对.针对饲料企业的特点和信息构成情况，本文在建立企业内部网，开设企业与外部信息交流站点及开展电子商务等方面提供参考.