Abstract:The present paper deals with the morphology of the olfactory organs of the skates, rays and chimaeras, in correlation with the classification and ecology. Anato- mical investigations had been carried out in 42 species belonging to 25 Genera. 17 Families, 5 Orders and 2 Subclasses.According to the size of the opening and diameter of the olfactory sac, they all belong to the cup-shaped pattern, usually the opening of the olfactory sac is larger or at least 2/3 to the long diameter of the sac. They can be divided into 3 subpatterns, e. g. 1) Elliptical subpattern as in most skates and rays, 2) Broad and compressed, kidney-shaped subpattern, as in Rhinopteridae and Mobula (fig. 12, 13), 3) Rosetteshaped subpattern, the rachis is broad in the middle of the sac and the primary lamellae are arranged in rosette shape, such as in chimaeras. The primary lamellae in the former two subpatterns are arranged in pinnate parallel shape.Detailed measurements show that the olfactory epitbelium grows by increase in size and number of primary and secondary lamellae. The number of primary and secondary lamellae in same species and same size of different individuals are almost similar. The number of secondary lamellae are numerous in the middle portion of the olfactory sac and gradually decrease to each side (Table 1,2). The shape of secondary lamellae have 3 patterns, viz. 1) needle-shaped; 2) leaf-shaped; 3) double-leaf shaped.The skates and rays are called "Olfactory fishes", they possess particular acute sense of smell; the olfactory organ is more important than the visual organ. According to taxonomical and ecological features they are divided into 3 groups: 1)in Pristidae, Rhynchobatidae, Rhinidae, Rhinobatidae the dorsal and caudal fins are well developed and the tail portion strong. They have no nasoral groove, anterior nasal flap less developed, the nostrils are almost entirely exposed, the olfactory tentacles are very short, the inner wall of the olfactory sac and the free edge of primary lamellae bear numerous placoid scales, which can prevent objects entering into nostrils to damage the lamellae. The current of water through the olfactory sac is induced by the forward motion of the sawfishes and guitarfishes. Their primary lamellae are numerous. 2) in Rajidae, Urolophidae, Dasyatidae, Gymnuridae the inner margin of anterior nasal flap is joined across a broad isthmus in front of mouth and expanded rearward on either sde as an extended curtain, the expossed nostrils are small and have nasoral groove. The tentacles on the upper free side of primary lamellae are well developed, those on the anterior side near incurrent opening are larger and longer than those on the posterior side. The current of water passing through the olfactory sac is induced by the movement of tentacles. The number of primary lamellae are very few, and in the Torpediniformes being the fewest. 3) in Myliobatidae, Aetobatidae, Rhinopteridae and Mobulidae, they can "fly" swiftly in the water. The inner nasal valve is well developed in Aetobatidae and Rhinopteridae. The current of water through the olfactory sac is induced by the forward motion of the rays, and by movement of tentacles. The number of primary lamellae is 126—216 in Myliobatidae and Aetobatidae but in Mobulidae 242—254.

Abstract:Five different kinds of canned fish were tested on petri plates with two specially constructed mutants of Salmonella typhimurium——TA98 and TA100(Ames Test).Mutagenic activity was detected in the smoked fish of the five samples. It showed that this processed fish contained base-pair substitution mutagens which required metabolic activation.The smoked fish which was clearly positive in the test should be considered as potential human health hazards, and should be thoroughly tested in animal systems. These studies have shown that the smoked fish might possibly present traces of polycyclic aromatic hydrocarbons.

Abstract:The method and steps of in-door indueed breeding of Huditapes Philippinarum is discribed in this paper: The sex-matured parent elams should be air-dried for a period and then soaked in ammonia sea water by adding with diluted solution of famale sexual glannds for inducing spawingThe results obtained from the experiments are as follows: Spawning could be successful with 1/2—24 hours of air-drying. Generally, the optimun period of airdrying should be controlled within 16-hours. The range of effective concentration-of ammonia and seawater for inducing was 0.00015—0.00225N. The best results are obtained from the parent clams soaked in 0.00075N of ammonia and seawater with addition of female sexual gland solution at a concentration of 25—150mg/L for 14 hours. The sucess rate reaches to 96.2%.The characteristics for the method described above are: short cryptic period, usually within 30 minutes; high spawning rate about 72—100% during the natural spawning season high festility, The rates of fertilization, incubation and the development of larvae into the viliger stage nearly reach to 100% and they can normally develop into spats under in-door conditions.

Abstract:The present paper deals with the freeding habit of the filefish Navodon septentrionalis (Günther) distributed in the outer region of Dong Hat.There have been examined and analysed 852 samples which were collected from the bottom trawling explorations during the period from January to June in 1974 to 1976. The results may be summarized as follows:1.Naxodon septentrionalis is a kind of omnivorous fish mainly feeding on the planktonic crustaceans as well as mollusca and corals.2.There are two peaks of feeding activity occurring in February to March and May respectively and the valley is in April, probably concerned with breeding activities.3.Thefeeding activity and the food composition of filefish varies in different areas, the southern shoal being the highest, the middle one the second, and the northern shoal the lowest.4.The feeding habit of Navodon septentrionalis also exhibits the phenomenon of diurnal vertical movement.

Abstract:N-paraffin yeast is a new source of protein for animal food. Recently, experiments with high and full doses of n-paraffin yeast have been made to confirm whether it is safe to feed the fish. The food used in test groups was mixed with n-paraffin yeast in different percentage 30%, 50%, 70%, and 98%, while the control group was fed on 70% of fish meal. After three months raising, the results are as follows:1. The growth rates of the test groups were higher than that of the control group, while the group with 30% of n-paraffin yeast was found to be the best of them.2. The amount of red blood cells and white blood cells, and the volume of red blood cells were all within the range in the control group.3. The chemical indices of fish blood were as follows:cholesterol, serm amylase and ZnSO_4 turbidity were all within the range of those in control group, but glutamic-pyruvic transaminase in the test group of 30% was found somewhat little higher. The reactions of the thymol turbidity showed weak positive.4. The amount of 3,4 benzo pyrene remaining in the muscle were all within the range of 0.70—0.14 p. p. b., under the permissible level (1.00 p. p. b.).5. No abnormality was found in the appearance of internal organs(liver, kidney and intestine) and microscopic examinations.6. GeneraIly, the maturity and the absolute and relative broods in test groups were higher than those in the control group.

Abstract:An attempt is made to generalize the present status of exploitation of natural resource of cephalopods in the West Pacific. This paper presents: (1) characteristics of the present exploitation, (2) an account of the biology of the economically important species,(3) resource structure and fluctuation of the catches, (4) potential stock biomass and prospects.According to the data of prey-predator relationship, 5,500,000—7,500,000 tons of potential stock biomass of cephalopods in the West Pacific were estimated.

Abstract:本文用组织学方法研究了当年池养普通鲻鱼(Mugil cephalus Linné)的雌雄同体现象。描述了精卵巢发育情况,随着月份不同,雌雄生殖细胞的比例有明显变化,10月份雌性生殖细胞占优势,到了12月份雄性生殖细胞占优势。这种现象称中间性现象(Intersexuality),也即存在性转逆(Sex-reversal);属于偶然的雌雄同体(Accidental hermaphroditism).也是幼期的雌雄同体(Juvenile hermaphroditism)。

Abstract:Cyprins carpio yuanjian wu et al. is a local type of Cyprinus carpio rubrofuscus Lacépède. Its morphological features are, head small, body spindle-shape and compressed laterally, greatly convex on dorsal surface, with dark-grey colour on the back. It lives in rivers and lakes on the plateau of subtropical region. The Red Purse Carp is a variety of the commen carp, living in the still waters of the mountainous areas in the basins of the middle and lower parts of Chang Jiang river. The external Features of the fish are head small, body short and high, with a large and fleshy belly, colour reddish orange. It is also a district variety. In 1974, the two types of carps, the Yuangjiang Carp and the Red purse Carp ♀ were artificially crossed and their F_1 hybrids display marked heterosis。 The F_1 hybrids show that the ratio of body length to body depth is from 2.35 to 2.55, higher than than of their parents. Individual hybrids can grow to an average size of about 1,000g within one year (under the condition of polyculture in a density of 30-60 individuals per mu). The growth rate of the hybrid is much higher than that of Red Purse Carp by 52.3%, that of the Yuanjiang Carp by 28.05%, and that of the wild carp in Chang Jiang river by 45.5%. It shows that the difference between the hybrids and its parents is highly significant(P0.001); the fish flesh percentage of the yearling is 77.8% on an average, the fat content in the muscles is 3.68%, the protein content is 18.37%. The adults of the hybrids are easy to be harvested. They also possess many other economical importances, such as high survival rate, diseases resistance and high fertility

Abstract:自食性鱼类是一些捕食同种幼鱼的鱼类,在补充时期自食性鱼类的幼鱼大量被同种鱼作为饵料而捕食。自食性鱼类一般在长到一定年龄(t_n龄)后才开始捕食自己同种幼鱼,所以这种鱼类在补充时期的自然死亡和本种群的t_n。龄以上鱼的数量有关。如果t_n龄以上鱼的残存量愈大,补充群体被捕食死亡部分就愈多。本文分:(Ⅰ)t_n=t′_ρ;(Ⅱ)t_n>t′_ρ;(Ⅲ)tn<t′_ρ三种情况,推导出单位补充量产量方程如(3)、(4)、(5)和(6)、(7)、(8)等式。 应用东海群带鱼各参数计算的结果,用自食性鱼类模式得出的最高产量出现在t′_ρ=1龄左右,而用Bevreton-Holt模式得出的最高产量出现在t′_ρ=3龄左右。显然自食性鱼类模式计算的结果比较符合现实情况。