Abstract:The present paper deals with the larvae of tuna-like fishes collected aroundwaters of Xisha Qundao of the Nan Hai, during the period in January 1975 to May1976. The larvae and postlarvae of the tunas, tuna-like fishes, were described. Theybelong to Scombridae (Grammatocynus bicarinatus), Thunnidae (Katsuwonus pelamis,Euthynnus yaito, Auxis thazard, Thunnus thynnus, Thunnus albacares, and Thunnusobesous). The morphology of these tunas larvae were described as will as the ecology andspawning seasons. There is a close resemblance at same body length between larvae of Katsuwonusoelamis and Thunnus thynnus, in the distribution of chromatophores on the ventrallobe of the tail. The head of the former is large and long (about 30-40% of the bodylengthes) but of the latter is small and short (about 29.33-32.93%). They also differfrom each other in the following features.

Abstract:Cockspur (Echinochloa of Gramineae) is an aquatic or semi-aquatic plant widelydistributed in various parts of China. Since the year 1976, experiments of plantingcockspur in fish-pond and of submerging as green manure for the purpose of rearingfish fingerlings have been carried out. The fish yields range from 75 to 100kg/mu have been obtained without supplementary feeding or manuring. The paper deals with the techniques of planting cockspur and roaring fingerlingsin fish-ponds. An account of the dynamics of the concentrations of nitrogen andphosphorus in bottom mud and in water of the experimental ponds and of the liberationof nitrogen and phosphorus during the process of decomposition of cockspur and theinfluence on the abundance of planktons is given.

Abstract:The present paper deals with the study of the gonadal dovelopment of groy mul-lets. It is aimed at knowing whether the grey mullets can spawn or not in given condi-tions. The characteristics or oocytes in different stages of development were noticed. 1. The cycle of the sexual maturity of the grey mullets is in accordanco withthe development of the gonad. First maturation of the fish is at the third year andthe spawning time is between November and December. 2. The growth and development of grey mullets in the Xinglin Wan are similar tothose in Florida,but they are faster than those in the Mediterranean Sea and the Black Sea. 3. The grey mullets in the closed Xinglin Wan require artitificial injection withhypophyses to promote their maturation. 4. The ovaries of the Ⅱ, Ⅲ, Ⅳ and Ⅳ-Ⅱ stages, were examined in 104 femalesamples. 5. The gonad is absorbed after December, because the fish are isolated from thespawning ground in the open sea. The process of absorption is taken place from the lastten days of November to January and February next year.

Abstract:The potential fish productivity of Dong Hu according to the method of energybudget, the food supplying capacity of phytoplankton for the silver and bighead carpsand their conversion rate, and the potential productivity of the two species and therational stocking rate of their fingerlings are estimated. The annual net production of phytoplankton of Dong Hu is 80% of its grossproduction, offering a food-supplying capacity of 10, 025 tons of oxygon, or 35, 188×10~6 Kcal., equal to 61,153 tons (fresh weight) of phytoplankton. The food coefficient of phytoplankton (fresh weight) for the silver and bigheadcarps is 82 and 47 respectively, and the energy conversion coefficient is 39.18 and22.69 respectively. The potential annual production of the silvar and bighead carps of Dong Hu mayreach to 1, 368, 000 kg i. e. 789 kg/ha, or more. The number of silver and bighead carps fingerlings not less than 13.3 cm inlength to be stocked each year should be 2, 090,000 and 1, 100, 000 respectively.

Abstract:The bluish green pond "water bloom" is generally recognised as the typical waterquality of most high-yield fish ponds in Wuxi fish farms. A study of the ecology ofthe fish pond, the "water bloom", the biology of the dominant algae and its value as fishfood has been carried out. It was found that the bluish green color of the pond water mainly is formed bythe "water bloom" of a dinoflagellate(Gymnodinium sp.), which multiplies enormouslyunder the favorable conditions of adequate illumination, warmth, and heavily manuredwaters. It is very sensitive to environmental changes. If the algae are over populated,the pond water would damage and cause the suffocaiton of the pond fish. The integratedmanagement of heavily manuring, continous addition of freshwater, and the reasonableoperation of aerators will promote and control the multiplication of the algae. Microscopical examination on the digestive tracts showed that large amount of thealgae were taken by the silver carp, bighead carp and the finglings of common carp,crucian carp and tilapia. Obviously the "water bloom" of the algae effects greatly the production of fish pond.According to the statistics of the Fishery Team No.1 of Helie People's Commume, thefish ponds having "water bloom", the net yield of silver carp and bighead carp willincrease 33.4-37.5%.

Abstract:三十年来,淮河流域兴建了大批水库和闸坝,在人为控制条件下,水文情况发生了巨大变化。本文报道了对变化后淮河青、草、鲢、鳙、鳊、秦鱼类产卵场所进行的调查;对鱼卵、鱼苗的流量和成色,产卵场的分布、规模及变迁情况,产卵场的环境和促使产卵的主要外界条件作了介绍。调查的结果表明,在淮河径流调节后家鱼产卵场依然存在而且分布广泛,特别是蚌埠闸下形成了新的产卵场,对淮河、洪泽湖及运河以西各个湖泊经济鱼类的资源补充起了一定作用。为了保护资源。本文提出应对蚌埠闸、老铁桥下和信家湾——王咀子三处的产卵场规定禁渔期的建议。

Abstract:For the purpose to select suitable food for cultivation of the larvan of Ruditapesphilippinarum,a series of comparative experiments had been carried out. Several speci-es of unicellullar algae were selected for test, and the results obtained were as follows: 1. Food should be given at the stage of veliger. At this stage, the larvae showed apreferable selection for the size and activity of the feeding algae. If the small-sizedand highly multiplicative unicellullar algae could be provided in time, the period ofcultivation of the larvae might be shortened. 2. Six species of unicellullar algae were used in the tests. The result showed thatDicrateria zhanjiangensis, Cheatoceros sp., Cheatoceros simplex and Phaeodactylumtricornutum were found to be better. Survival rate could reach to 36-50%. When fedwith Heterogloea sp. growth apeed and survival rate of the developing larva were verylow. The big size and the strong activity of Platymonas sp. could hardly be graspedby the larvae. 3. If the larvae were fed with mixed food of Dicrateria zhanjiangensis andCheatoceros sp., or Dicrateria zhanjiangensis and Phaeodactylum tricornutum, the deve-lopment of the larvae and the survival rate raised to 70-71%. 4. The feeding quantity is also important in the cultivation of the larvae. Experi-ments showed that at begining the quantity should be controlled at 15000 ind./ml. perday, two days later it should be gradually raised to 40000-50000 ind./ml. per day. 5. By feeding with senescent algae, there was evident effect on the growth andmetamorphosis of the larvae. Aged Cheatoceros sp. gave no evident effect, but agedDicrateria zhanjiangensis had evident effect on the larvae and varying with the degreeof senescense.

Abstract:This paper deals with a study on the white speckle disease of garrupa, Epinephe-lus akaara (Temminek et Schlegal). Results are as follows: 1. Pathogen: Petalosoma epinephelis Huang et al. sp. nov. The white speckle disease of the garrupa is caused by a parasitic ciliate. It is foundto be a new species belonging to a new genus of Chlamydodontidae. The ciliates attackthe gills and the skin of the garrupa. The new genus (Petalosoma Huang gen. nov.)possesses both the petaloid body andthe cytostome simultaneously, and so it is quite different from the other five genera ofChlamydodontidae. The type species of this genus is Petalosoma epinephllis Huang et al.sp. nov.. The new species has the body length from 45μ to 80μ (average 67μ) and widthfrom 29μ to 53μ (average 39μ). Its ventral side bears 32-36 rows of cilia. The oralbasketris formed by 12 trichites. There is a petaloid body in the rear of the cell. 2. Symptom: The parasites irritate the skin and gills of the fish, thereby, large quantity ofslime was secreted. The skin appeared white speckles. The infected fish always swimsslow and breathe with difficulty. It would cause high mortality. (a) Bathe the diseased fish in freashwater for 4 minutes.(b) Bathe the diseased fish in 2 ppm. copper sulfate solution for two hours andrepeat text day.

Abstract:The present paper is a description of two species of acanthocephala obtained fromthe naked earp, Gymnocypris przewalskii (Kessler) of Qinghai Hu during the yearsof 1963-1964. The parasite dwells at the anterior part of the intestine of thehost. 1. Neoechinorhynchus qinghaiensis sp. nov. Body elongate, cylindrical. Proboscis short, globular in shape bears three rows ofhooks, ench row having six hooks. The apical hooks are lange and the others small. The male: Body length 1. 82-3.70 mm; width 0.33-0.60 mm. Proboscis length68. 6-114.3μ width 62.9-112.9μ. Testis ellipsoidal. situated in the posterior part ofthe body. The female: Body length 2.86-5.33 mm; width 0.49-0.69 mm. Proboscis leng-th 91.4-114.3μ; width 108.6-137.1μ. Eggs ellipsoidal, 22.0-29.5μ by 16.1μ insize. Location of the parasite: anterior part of the intestine. Discussion: This species differs from the closely related N. rutili (Muller 1780)chiefly in body size, length of proboscis hooks and shape of the eggs. 2. Echinorchus gymnocyprii sp. nov. Body elongate,cylindrical. Proboscis elongate,cylindrical, armed with 14-16longitudinal rows of hooks, each row having 10-11 hooks, unequal in length. The male: Body length 7.28-10.73 mm; width 0.77-1.53 mm. Proboscis length 777. 1-1068.5μ; width 154. 3-354.3μ. Testis situated in theposterior part of the body. The female: Body length 15.14-28.91 mm; width 1.16-1.90 mm. Proboscislength 697.1-1142. 8μ; width 371. 4-457. 1μ. Eggs elongate, fusiform. Location of the parasite: Anterior part of the intestine. Discussion: This species differs from the closely related E. salmonis Muller 1784chiefly in body and egg sizes.