Abstract:This paper deals with rearing larval stage of mudskipper (Boleo-phthalmus pectinirostris) in reference to the feeding, development and the effectof different feeds on growth and survival of larvae. The brood fish were injectedwith HCG during the spawning season, the fertilized eggs were obtained by meansof semi-dry method. At one day after hatching, the larvae were reared in the outdoorcement pools, fed with different types of feeds and provided with sufficientaeration. The experiments inducated that there did exist a critical period of highmortality which occurred during 3-5 days after hatching. The deepest, sharpest andfastest physiological and ecological changes during the development of larvae occurredat the time of shift from endogenous (including mixed) nutrition to exogenous oneParticulate organic detritus of benthic diatoms decomposed by natural way may bethe initial diet of larvae. High survival rate of postlarvae(42.04%) was obtained andobserved at the end of rearing experiment. In addition to particulate organic detritus,copepods (nauplii, copepodites and adults) were gradually fed from six days afterhatching, and then the postlarvae grew well, with avervage total length of 6.15mm and average body weight of 1.24 mg at 16 days after hatching.

Abstract:This paper deals with the acanthocephaliasis of carp. The work wascarried out in 1985-87 at the Third Xinmin Fishfarm of Chongming County. 233diseased fish were vivisected and 964 parasites were observed. The detail of taxologicalcrucial characteristics were checked with scanning electron-microscope. The parasiteis a new species of genus Rhadinorhynchus in family Rhadinorhynchidae. This newspecies was designated Rhadinorhynchus chongmingnensis sp. nov. The pathogen, symptom and therapy of this disease are presented as follows: 1) Pathogen: Rhadinorhynchus chongmingnensis sp. nov. The male of adultparasite is 18.25mm in average length and 1.75mm in average width, the femaleaverage length is 23.59mm and 2.58 mm in average width. All over the proboscisare covered with fine fur. The crucial characteristics of this new species are 14longitudinal rows of 29-32 hooks on the proboscis. (see table 4 in the paper). The type specimen were preserved in The Fish Disease Laboratory, ShanghaiFisheries University. 2) Symptom: The disease is not very serious at all. When once a fish carries alot of parasites, it will cause death. The parasite mainly lives in the digestive tractof fish. After the probosics bores into the intestines wall, the granuloma will formaround the worm. This disease can infect to carp of size from 9-2,050 grammes. Itwould damage 60%, if 100% of fish are infected. 3) Therpy: The daily dosage is 0.6ml carbonei tetrachloridum per kilogram offish weight, mixed in fish food. Generally, if continually treating for six days, asatisfactory curative effect would be obtained.

Abstract:The artificial rearing of larvae and juveniles of S. constricta wasconducted on the basis of the results of study on the experimental ecological condi-tions of the larvae and juveniles. The larvae and juveniles were reared under theirsuitable ecological conditions such as temperature, salinity, aeration, sanitationof the culture medium and nutrition. The result of output was satisfactory. The yieldof each unit was between 5.46×10⁴ pcs/m²and 21.06×10² pcs/m², 10-20 times as much as the output under natural conditions. Therfore, it is worthwhile to putforward this artificial rearing method. Some potential problems with regard to theartificial rearing of larvae are also discussed, and the data obtained are expected toprovide for the overall and further study.

Abstract:This paper deals with the study of extensibility of netting yarnsmade of Yilun folded monofilaments under the load below its breaking strength. Theextensible charateristic of these netting yarns includes elongation, toughness andelasticity. The results of experiment are as follows: 1. By breaking test, the elongation value of Yilun monefilament netting yarnsof the weaver's knot and the straight (knotless) acted under half knot breakingstrength is obtained. 2. The toughness and coeffecient (Q) by load-elongation curves were obtainedfrom breaking tests and by the insert value procedure of natural spline function. 3. The dergee of elasticity at various relaxed time is obtained by the elasticitytests under fixed elongation, then to get the relationships among the degree ofelasticity, diameter and relaxed time of the Yilun monofilament netting yarns.

Abstract:The growth characteristics of jellyfish (Rhopillema ascuLanta) which habitats in Liaodong Bay was studied and discussed. The results obtained with regre-ssion method are as follows:1) The relationship between the arch length of the individuals of jellyfish (L_t) and their total weight ( W_t) may be described with an equation as W_t=0.3932L_t^2.4 2) The relationship between the arch length and the diameter of the jellyfish(D_t) is linear and the regression is D_t=0.57+0.49L_t 3) The relaLianship between the weight of the umbrella-hart of individuals of jellyfish (W_s) and their total weight is linear, t.oo. The erination is W_t=1. 7743W_s一1775 4)The comgrowth pattern of jellyfish is different from that of fishes and shrimps. Since the grow of jellyfislz shrink after the first ten--day period of Septem-ber without asymptotic values, it is impossible to sliow the growth pattern of jelly-fish by means of regular asymptotic growth equation. Its growth pattern mav be rlesr-cribed with .polynomial expression as a function of time, via. L_t=4.2198+0.4146+0.2203t²+0.03824t³一0. 002249t⁶ in which,t and L_t= designate respectively the. time and arch length of jellyfish,the time unit is five-day. on this basis, the growth rate and growth pattern function of time is discussed.

Abstract:The age of clam can be determined by light penetration method.When a common light penetrates the shell of clam|the stiped pattern on the shellappears clearly. The bright and dark portions of the stripes are formed respectivelyfrom May to October and from October to Mae of the next year. The time of forma-tion of dark and bright portion is very definite among all of the age groups. There-fore|the absolute age of clams can be datermined by the bright-dark boundary onthe shell or clam.

Abstract:In the course of studying the artificial hatchely rearing of seacucumber Apostichopus japonicus, it was found that the survival rate of juveniles seacucumber was low. The period of development from seedling to juvenile was anothercritical phase in its life cycle. During this phase, the juvenile were mostr susceptible tothe adverse influence of their environment. The method of mathmatical statistics was applied to test the effect of severalfactors influencing the survival rate during the juvenile stage. Four factors wereselected, viz., settling density of seedling, types of feeds, temperature of the culturemedium, and the mode of water exchange. The results from the variance analysis anddirect observation indicated that settling density and types of feeds were more impor-tant than other two factors in fluencing the survival and growth rates of juvenilesea cucumber. A settling density of about 0.2 individuals/cm~2 was optimal, of 0.5individuals/cm~2 less favorable. A filtrate of ground Sargassum proved to be the bestfood for juvenile, and the next best was a mixture of ground Sargassum and Dicra-tina.

Abstract:金鸡湖位于北纬31°17′,东经120°19′,为长江下游平原型浅水湖泊,面积717.9公顷,平均水深1.5米。1956年起人工放养,至1973年的18年间每公顷渔获量年均255千克。1974年起经营者从湖泊生态学管理原则出发,逐步实施综合增产技术措施,渔获量显著增长。

Abstract:细鳞泥鳅(Misgurnus mizolepis Gunther)是鳅科鳅属的鱼类,俗名“肉泥鳅”。个体比泥鳅大,习性与泥锹相似。底栖杂食性,很容易饲养。是一种小型鱼类,可以食用,也可做其他鱼类的饵料。除高原外,全国均有分布。细鳞泥鳅消化系统与鲤科的草鱼及鲤鱼的消化系统有不少相似处,但也有其独特性。故做此项工作,为鱼类消化系统的进一步研究,提供参考。

Abstract:Colossoma brachypomum native to Amazon region was introducedinto China mainland in 1985. After a comparative study it was identified to beColossoma brachypomum (Cuvier, 1818). The fish has following morphologicalcharacteristics: Body laterally compressed shaped; Depth 1.9±0.33; in standardlength; Head 3.8±0.47; Length of caudal pedunele 13.4±1.33; Its depth 8.0±0.63;Snout 4.2±0.89 in head; Eye 6.0±0.35; Interorbital space 1.8±0.2; Depth ofcaudal peduncle 0.6±0.09 in its length; D iii-13-15,P i-15-l7,A iii-22-23, V i-7-8;Lateral-line scales 87-94; Gill rakers 32-38. It was found in cultural practice thatthe fish is omnivorous, and can tolerate high salinity (10 PPT) and low levelof dissolved oxygen (0.48mg/L). The suitable growth temperature is 22-30℃, butit will die below 8℃. It is considered to be a potential cultivated freshwater speciesdue to its easy culture, fast growth and convenient capture with a sein. Thechromosome number of the fish is 2n=54, n=27.

Abstract:养殖鱼类的优良品种或品系,无论是原有的、引进的、还是新培育出来的,一旦因杂交而丧失了它们原有基因库中基因的配套,就很难恢复。因此,保存原始的优良品种或品系,是保护国家生物资源的重要措施。

Abstract:Pinnotheres sinensis shen is very harmful to the cultivation of Mytilus eduis linnaeus. In order to limit or eliminate its distruction, we made threeyears of investigation on the habits and propagation characteristics of P. sinensis aswell as its danger to Mytilus edulis. Emphasis was placed upon the alternation ofgeneration of P sinensis. It was suggested in the paper that the present cycle ofartificial rearing of M. edulis be changed so as to avoid the great damage caused by Psinensis.