Abstract:The present paper deals with the changes in the Ca⁺⁺-ATPase activity ofmyofibrillar protiens from minced fish meat of grass carp (Ctenopharyngodon idellus)in refrigeration. The effect of several kinds of factor on Ca⁺⁺--ATPase activity wereexamined. The Ca⁺⁺-ATPase activity was considered to be useful in evaluating thequality of minced fish meat in the refrigerating process.

Abstract:This paper deals with the effects of protien and carbohydrate contents in feedson the growth of black carp (Mylopharyngodon piceus) fingerlings. The experimentalfeeds were composed of casein, dextrin,fish-liver oil, powder of carboxymethylcellulose, mix-mineral and suitable amount of vitamins. The black carp fingerlingsused in the experiment were 37.12--48.32 grams in average weight, and rearedunder water temperature of 24--34℃ for eight weeks.Computing by straight--line regression and parabolic regression indicates that theoptimal proportion of protien in the feed should be 29.54--40.85%. The interactionbetween protien and carbohydrate is obvious. When the fingerling were given with afeed containing 37--43.3% of protien and 9.5--18.6% of carbohydrate, the fishgrow very fast. Therefore, the content of carbohydrate in the feed for black carpfingerlings about 20% seems to be suitable.The protien content in feed directly affects the content of protien, fat and car-bohydrate in fish body and the liver. The liver starch of fish is increseased with the increase of carbohydrate content in the feed.The digestive rate of protien in black carp fingerlirgs is affected by the quantityof carbohydrate contents in the feed. When carbohydrate content below 30% in feed,the protien digestive rate can be kept at 92%; while the carbohydrate content wasincreased to 43%, the protien disgestive rate will be greatly decreased. The reason ofit may be that black carp is carnivorous.The hemoglobin of black carp fingerlings was measured. Except the starvedgroup is 5 g hem./100 ml all the rest groups are 5.8--6.5g hem./100ml. It is believedthat the composition of feed makes little effect on hemoglobin level of black carpfingerlings.

Abstract:Since 1976, a series of net-cage--culture experiments of tilapia and grass carpwere carried out in Dianshan Hu Lake, Qingpu County, Shanghai, in order to verifythe appropriate technology.In 1976, a high yield of 306 kg/36M²(8. 5kg/M²) in 135 days was obtained, butthe conversion rate of feed was very low. Therefore, another experiment in culturingtilapa was carried out in 1977. The aim of this experiment was to find out the appro-priate technique of cage culture suitable to our country. Nine 2×2×2.5 M cages wereinstalled in the Dianshan Hu Lake for the experiment. After 80 days rearing, theyields obtained ranging from 10.6 kg/M² to 35.15 kg/M². The rate of conversionrange from 2.7 to 5.2.The size of the net cage was 2×2×2.5M, and the stocking density was 4,200individuals/M², the average weight of the fingerling was 1.68g. Feeding with drypellet composed of 10% fish meal, 40% fine rice bran and 50% soybean cake, at afeeding rate of 12.2% to 2.4% fish biomasa per day. After 120 days 388 kg was harvested. The rate of conversion was 2.16, In 1980, the same procedure applied torear grass carp in cage, and an average yield of 25.09 kg/M² (net yield of 14.5 kg/M²) obtained. The Conversion rate was 2.49. The economic value of grass carp ismuch higher than tilapia.The key factors to obtain high yield can be concluded as follows: (1) The cageshould be of medium--sized (20 to 60 M²). A feeding stage is necessary to set inside thecage in order to save the waste of the feed. (2) The optimum stocking density rangesfrom 5 to 10kg/M². Mono-culture of a high valued fish is preferable. (3) The diss-olved oxygen should not be less than 3 mg/L. (4) Nutritive feed with a total protiencontent over 35% should be available. (5) According to the difference of sizes, thefeeding rate ranges from 10% to 2% of fish biomass per day. (6) Effective controlof pest and fish diseases.

Abstract:Mactra chinensis inhabits in the shallow seas or inter-tidal zones adjacent to riveroutfalls by burrowing into the muddy sand bed 2--7 cm in depth. It can ambulateto some extent and has a great adaptability to the varied environment, such as theannual water temperature varies from -- 1.9--31.5℃, annual salinity varies from8.6--34.8% and also the seasonal dilution of salinity by outpouring of fresh water.The clamr lives chiefly on planktonic diatoms. The amount and components ofthe stomach contents at different sea areas and differant seasons have been observedand it is found to be in accordance with the species which were taken as diet underthese specific enviornments.The clam is gonochorism. It reaches its sexual maturity in a full year term. Theripened sexual cells discharge in batches. Its spawning period starts in late of May atthe water temperature over 14℃. The temperature can be raised by artificial metho-ds. Expediting on parturition can be obtained by induced spawning or by running-w-ater stimulation.The ovum of the clam can be artificially fertilized and normally developed. Thelower limit of temperature for embryonic development lies near 10℃. The larvae livechiefly on small-sized unicellular algae.The clam grows fast in the first three years, especially the first two years, itssize reaches to 3 cm at the end of first year and 4--5 cm in the second year,while inharvesting its size reaches to 5 cm. At the beginning of June, its soft portion (meatportion) becomes fully developed with a most production rats of 40.32%.Appendant formation can be observed at the basal portion of outer gill of theclam.

Abstract:Studies on rheological properties of polysaccharide solution from Eucheuma gela-tinae were carried out. A sudden change on the relations of the the shear stress τ vsshear rate D, lgD vs lgτ, D vs η and the thickness index and flowing behavior indexof the polysaccharide solution was observed at temperature 50--60℃.It was found that the slope of the plot line of In n vs 1/τ based on the Arrheniusequation: n = A. e^(v/RT) at the temperature ranges of 30--50℃ was differ from that of60--80℃. It was showed that the flowing activation energy at 30--50℃ was differentfrom 60--80℃, the change of flowing activation energy occurred at 50--60℃.Because of the soddenly reducing on the thickness index of the polysaccaridesolution at 50--60℃ as pointed out above, the application temperature over 50℃ mustbe avoided in using the polysaccharide as a thickner and stablizer.It was found that thickness of the polysaccharide was higher than sodium alginateand partial hydrolytic polyacrylamide (with a hydrolytic degree of 20% and a mole-cular weight of 2.1×10⁵) and the polysaccharide from Eucheuma gelatinae was a goodthickener.

Abstract:The seasonal regularity of strobilation of edible medusa, Rhopilema esculenta,hasbeen observed for three years, the medusa were reared in three different kinds ofhabitats, i. e. the natural sea inlet, the indoor concrete tanks and aquaria in labora-tory. This paper deals with the content about the season of occurance, velocity of pd-eveloment, frequency of repetition of strobilation, number of ephyrae produced andthe development of abnormal strobila of the medusa.The strobilation begin to occur in spring each year when the water temperaturerises up to 13℃, then ephyrae are released at above 15℃. The samo individual canstrobilize repeatedly 6-13 times from the beginning of strobilation in spring to the endof antumnwhen the water temperature falls below 15℃. The first time of strobilationoften produce 5--14 ephyrae. In the course of repetition of strobilation, the number ofephyrae formed each time gradually decreases. The strobilae occurred in summergenerally only poosesses one or two segments. The average developmental period inproducing an ephyra is about 2.1 (i. e. 1-4) days. The shortest and longest intervalsbetween two periods of strobilstion are 3 and 28 days respectively, but generally isabout 10 days. The abnormally developed strobilae can be divided into many categories,i. e. develo pment in deficiency, development in stagation, development in reverseand develo pment in both ends.

Abstract:The present paper dricribes two new species of Dactylogyrus, collected fromProcypris merus Lin. in the Bo' ai, Xiyang Jiang (of the Zhu Jiang River system).Syntype-specimens are deposited in the Department of Biology, South China NormalUniversity.1. Dactylogyrus cystovagina sp.nov.(Fig. 1)Body 0.494--0.585×0.173--0.205mm. Marginal hooklets 0.021--0.039mm intotal length. Central large anchors of D.wunderi type;total length 0.059--0. 070mm,basal portion 0.044--0.047mm, point 0.023--0.027mm, inner root 0. 034--0.036×0. 010--0.011mm, outer root 0.005--0. 008mm. Connective plate 0.009--0.010×0. 043--0.057mm in size. Supplementary plate V-shaped,0.003×0.010--0.017mmm size.Copulatory organ is 0.047--0.057mm in total length. Copulatory tube curved andstrong in shape, 0.039--0.042mm in total length. Supporting apparatus is halberdli-ke, 0.047--0.057mm.Vagina is peach--like, 0.023--0.029×0.016--0.020mm in size. Description is based on 3 specimens.Remarks: This worm is similar both to D. vastator and D. minutus, but it differsthe latter in the maseures of cuticular structures of the anchors, tube and supportingapparatus. The new species is near to D. clasterocirrus in the central large anchorsand copulatory tube, but differs from the structure of the supporting apparatus andshape of the supplementary plate.2. Dactylogyrus boaiensis sp. nov. (Fig. 2)Worm of medium size, being 0.091--0.130mm wide, 0.442--0.546mm long.Marginal hooklets 0.021--0.042mm in total length. Central large anchors of D.wunderi type;total length 0.048--0.057mm, basal portion 0.042--0.043mm, point0.013--0.017mm, inner root 0.016--0.022mm, outer root 0.005mm. Connectiveplate 0.005--0.008×0.039--0.044mm. Supplementary plate T-shaped, 0.008--0.026mm in size.Copulatory organ is 0.044--0.055mm in length; Copulatory tube S-shaped, 0.036--0.052mm in length. Supporting apparatus is lotuslike, 0.029--0.039mm.Vagina resembles a magnolia in bloom, 0.023--0.034×0.008--0.010 mm in size.Description is based on 4 specimens.Remarks: The new species is distinguished from the other species of the genus byits characteristic structure of the vagina and shape of the male genitalia.

Abstract:Asphyxiation point and lethal temperature for the fingerlings of mullet wereexperimentally dertermined. It was found that the lethal high temperature for thefingerlings of mullet was 36℃ and the range of tolerance may be started from 1℃.While the dissolved oxygen droped to 1.18--0.9mg per liter, the fingerlings comeup to the water surface, and at 0.7--0.93mg pe liter (at 37℃) or 0.52--0 .42mg perliter (at 25--28℃), the fingerlings died in asphyxia.

Abstract:本文从鱼脑乙酰胆碱酯酶系统、抗冻蛋白基因调控系统、同工酶开关合成系统以及代谢系统等四个方面综述了近年来鱼类对环境温度适应的研究概况,并分析讨论这些研究结果,同时提出遗传改良某些亚热带鱼类优良品种抗寒能力差的可能性。