Abstract:The stages of development of the medusae, Rhopilema esculenta from fertilizedegg, planula, scyphistoma, strobila, and ephyra to young medusae were observed inlabolatory and described in this article. The medusae are dioecious. Fertilized eggs develop exteral to the parent body.planulae are formed 7 hours after fertilization. Most of the planulae metamorphose intoscyphistomae with four tentacles in 3 or 4 days, then 16 tentacles in 15--20 dayswhen the scyphistomae grow up. During the course of growth and after full growth,the scyphistomae continuously form podocysts, from which new scyphistomae bud out.It is a way of asexual reproduction. Two months later strobilation takes place attemplature 18--20℃. Generally a strobila can produce 6--10 ephyrae. A typical ephy-ra possesses 8 pairs of rhopalar lappets, 8 rhopalia and 4 gastric filaments. Lappet istalon-shaped and usually has 4--6 branches, the distance between the tips of the twosymmetrical lappets being 1.5--3.0 mm. It needs about 15 days for the young medusaeto grow to about 20 mm in diameter of the umbrella when cultured in laboratory, andmay attain 50 mm in diameter within 30 days. In the sea the medusae need 2 to 3months of growth from ephyra to maturity with umbrella 250--450 mm in diameterin the Liaodong Wan.

Abstract:On the basis of species discrepancies of responsiveness to LRH--A, serum gonado-tropin (sGTH) levels of the mature female carps and immature female silver carpwere compared after cardiac injections of LRH-A at two different timos of a day.Fish sera were sampled at intervals either within 1 hour or during a 24--hour period.The sGTH concentration was measured by radioimmunoassay. In all cases, dealingwith the mature fish held under 18--20℃ two distinguished peaks were observed,one within 5 minutes and the other 5--6 hours later. The second peak was notdetectable in immature fish. This may signify that the second surge of GTH was moreimportant than the first in inducing spawning. When carp was subjected to lowertemperatures (11-13.5℃), the occurrence of the peaks was much delayed, which is inaccordance with the fact that when water temperature drops down beyond optimum,the response to the analogue is prolonged or even suppressed as has been found in farmpractice. When silver carps receiving LRH-A 23 days after the first ovulation which wasinduced by the same hormone analogue, the sGTH pattern was similar but higher in magnitude. Anatomical examination showed that ovaries had significantly proceededto the IV stage of maturation. though the GSI values were lower than that prior to thefirst ovulation. The long-term effect of LRH--A in terms of acceleration of ovarianrecrudescence in the postspawning phase of the reproductive cycle was apparent.

Abstract:By using the technic of tissue culture we have successfully established a strain ofcomplex of epitheial-like and fibroblast-like cells from the snout tissue of grass carp(Ctenopharyngodon idellus), and it is denoted as strain ZC--7901. The medium used inthe cultivation is"199" supplemented with 15% fetal bovine serum containing a mode-rate amount of antibiotics. The incubation temperature is at 25--28℃. A substrain ofsingle epitheial-like cells is also obtained from ZC--7901 cells of 11th generation, whichis named substrain ZC--7901S_1. At Present both the strain and substrain have been maintained in proliferationfor over 22 months through 120 and 90 generations respectively, and the cells ofthem are able to reproduce with approximately 1.5×10~5 cells per millilitre in con-centration. About 4 days, a monolayer cells can be found clearly in the culture. After36 hours, the index of mitotic division of the ZC-7901 is 36.5‰, while that of theZC-7901S_1 is 32.3‰; and then at 156 hours after propagation the former is gradullydecreased to 12.3‰ and the latter to 14.3‰. The chromosome number of each cell inthese two strains is 2n = 48.

Abstract:The scales of the striped mullet, Mugil cephalus Linnaeus, used for age de-termination were collected from Xinglin Wan of Xiamen, a brackish water bayinclosed by dam, during the period from September 1961 to October 1962. Thedistinction between the true annulus and the false annulus has been described. It isconfirmed that breaks were formed annually, dividing the scale into zones whosedimensions were related to tbe growth of the striped mullet. New annuli began toappear mostly in the months of October and November. The striped mullet matures at3 years old and the growth rates decreased after the adult stage. The length--weight relationship formula was calculated to be W= 6.492×10~(-5)L~(2.7768), the relationship between the scale length and standard length was expressed tobe R= 0.031 L-0.8359, where W, L and R represent body weight (excluding gutand gonads) in grams, standard length in mm and scale length in mm respectively. Itwas found that the growth of the striped mullet in Xinglin Wan corresponds to vonBertalanffy's growth equation, then we obtain W_t = 4864(1 - e~^{(-0.818(t+1.171))}~a, L_t = 685. 1 (1-e~^{(-0.818(t+1.171))}.Here W_t is body weight (excluding gut and gonads) in grams at the age of t, and L_t isstandard length in mm at the age of t. In order to increase the production of thestriped mullet in Xinglin Wan, it is necessry to prohibit the capture of young fish,suggested minimum legal harvestable age and size of this fish may be 2.5 years old,450mm in length and 1500 grams in weight.

Abstract:This paper describes some observations made mainly on the growth of raftculturedmussels (Mytilus edulis L.) in Jiaochou Wan, Shandong Province. The growth rate ofthe mussels varies with the season and with age. In the first year, they grew very ra-pidly in shell length during the period from August to October, the average increment was about 10 mm per month and the greatest increment was reached in October. AfterNovember their growth rate became gradually slower until it almost ceased or entirelyceased to grow in February the next year. At the end of the first year, the maximumlength reached about 40--45mm. Compared with the first year, the growth ratewas slower during the second year, with the increment averaging 5 .7--6. 0 mm permonth in the period from April to August, the greatest increase was jn July. As tothe reared spring spats, the growth rate reached its peak in August and Septemberduring the first year, 1--2 months earlier than that of the natural ones. The increase in shell weight of the natural spring spats transplanted from Yantaiand Dalien are shown in Figure 4. Generally speaking, it Increased markedly fromMay to October, with the maximum value of 2 grams per month in August, 1 monthlater than the peak increase in shell length. The increase in shell weight was faster inthe second year than in the first year and about 80% of the total shell weight was incr-eased during the second year. In the winter although the increment became slower, the flesh still continued toincrease and reached its peak again in late March the next year, and the mean indivi-dual dried flesh weight then was 1.2--1.3 grams. From April to May the flesh weightdecreased markedly due to the spring spawning, after which it began to increase againfrom June and reached its fall peak at the beginning of October, the dried flesh weight then averaging 2. 5--3. 0 grams. From mid-October to November it decreased once morebecause of the onset of the autumn reproduction, and gradually recovering again fromDecember onward. The reared autumn spats fertilized at the beginning of October, transplanted toand cultivated in the sea in mid-December, grew to 7-8 mm long in late May or earlyJune the next year, during which time they were suitable for attachment to cultureropes in flowing water, These spats grew to about 59mm in late March the third year,every 60 individuals weighing about 1 kilogram, They were harvested at this size. The spats attached on wharves grew rather slower and were less than 20mm inaverage length through a full year, attaining only 1/3 the length of those grown onthe cultivating raft.

Abstract:Naturally the habitat of the sea cucumber (Stichopus japoicus Selenka) is in thenorthern China Sea. Experiments were carried out to transplant them to the southern China (Xiamen) for the purpose of culture and artificial breeding. They were able tolive in the indoor concrete tanks, both adults and juveniles developed very well attemperature 27-29℃ in summer. After four months the adults attained sexual maturity. They spawned twice in Ap-ril 1978. The fertilized eggs hatched and developed into more than twenty thousandsjuveniles. A part of them were reared in indoor tanks, In August, juveniles grewto about cm². in length. Food of the larvae mainly consists of Dicrateris shanjiiangensis, Platymonas,Nitzschia, Bunaleilla and Torulopsis, among them Dicrateria is the most favorableone.

Abstract:The hairtails, Trichiurus haumela (Forskal), is one of the most important fish inthe China Sea. In this paper the morphological charateristics of the eggs and the deve-lopment of the larvae, from hatching to about 14.7 mm in length are described. Mater-ials were obtained from artificial fertilization during the spawning season and alsocollected by plankton net at the mouth of Huang He, Bo Hai, northern part of theHuang Hai and off the coast of Qingdao in 1958 and 1964.

Abstract:The present paper deals with observations on the cycle of histological changes inovaries of the small yellow croaker, Pseudosciaena polyactis Bleeker. Samples werecollected monthly from Bo Hai and in the northern part of Huang Hai, in May, 1963to June 1964. 1) Maturity. Based upon the macro-and microscopic characteristics the matura-tion of the ovaries can be divided into six stages: Stage Ⅰ-Juveniles; Stage Ⅱ-includingimmature ovaries, and those recovered spent ovaries; Stage Ⅲ-ripening ovaries; StageⅣ-nearly ripe ovaries; Stage Ⅴ-ripe ovaries near spawning or spawning, Stage Ⅵ-spent ovaries and Stage Ⅵ-Ⅳ', Stage Ⅴ'-recovered ovaries. 2) Annual cycle of the ovaries. The ovaries enter into Stage Ⅵ-Ⅱ' in July-Aug.; Stage Ⅱ' in Sept.-Oct.; Stage Ⅲ in Nov.-Jan. (mostly in Dec.-Jan.) this is theoverwinter period; Stage Ⅳ in Mar.-May (often in April); Stage Ⅴ from mid-May tomid-June (mostly in May) this is the spawning period. After the fish releases onebatch of ova the ovary is in Stage Ⅵ-Ⅳ' (or Ⅳ') and later on developes to Stage Ⅴ'.Stage Ⅵ occurs in June. 3) Reproductive cycle Sections of ovaries of each successive age group (2⁺-15⁺)collected during the spawning season showed empty follicles. This indicates that thereproductive cycle of the small yellow croaker is of the plural cyclic type, the adultfish spawning every year. 4) Type of spawning. The ripe eggs of this fish are released at least two batchesin a breeding season. It is evident that sections of ovaries sampled from fishes beforeand after spawning all show oocytes of various sizes.

Abstract:The study on primary productivity of phytoplankton and biomass of plankton ofLongtou reservior was carried out during 1978-1979. The mean primary productivityof phytoplankton is 1.88gC/m² per day. The biomass of phytoplanton and zooplanktonare 5.764mg/L. and 0. 587mg/L respectively. Basing upon the samples of the Longtoureservoir, fish productivity of silver carp (Hypophthalmichthys molitrix) and big-headcarp (Aristichthys nobils) and rational stocking of an aquatic ecosystem are discussed.

Abstract:1. For the preparation of hypnean from Hypnea sp. prior to extraction the algaeshould be treated with Baume' 20°NaOH at room temperature for 2 days, and rinsedwith water. The treated seaweed was then extracted with 15-20 times of its quantityof 0.04% dilute H_2SO₄ solution at 100℃ for 1-1.5hr. After filtration, to the filtrateKCl was added to bring its concentration to 0.2-0.3%, and the solution was allowedto gelatinate. The gelatine was frozen, thawed and dried. 2. The gelatinous strength of hynean was affected by electrolyte markedly. Theorder of effect by cations is:Ca(⁺⁺)K⁺, Cs⁺, Rb⁺Na⁺, Li⁺, NH_4⁺, and by anionsis: Cl^-NO_3_-, SO₄-I_-CO_3_-. 3. The setting point of hynean was affected by KCl, it was increased with increa-se of concentration of KCl. 4. The culturing effects of bacteria (Salmonella typhasa, Pasteure lla pestis,Shigella dysenteriae and Brusella abortus) in bynean media and in agar media werecompared. Hypean gave better results.