• Volume 3,Issue 2,1966 Table of Contents
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    • >PAPERS
    • A PRELIMINARY STUDY ON THE POPULATION OF THE RIBBON FISH,TRICHIURUS HAUMELA(FORSK?L),ALONG THE SOUTHEASTERN COAST OF CHINA

      1966, 3(2):106-118.

      Abstract (2000) HTML (0) PDF 552.14 K (1549) Comment (0) Favorites

      Abstract:Samples of spawning shoals were collected from five principal spawning grounds along the southeastern coast of China.Basing upon the comparative analyses of the morphological characters and serological study,together with the data on tagging experiment and the fishing seasons,the results are sum- marized as follows: The averages of meristic and morphometric characters between spawing shoals show slight statistical differences and the frequency distributions of meristic characters,such as the dorsal rays,the gill-rakers,etc.,are similar in different spawning shoals.Corresponding antigens,such as muscle proteins of different spawning shoals are serologically indistiguishable,but serologic diffe- rences have been found between muscle proteins from different species of rib- bon fishes.These relationships are represented graphically in a three dimension- al model.The results of the precipitin test closely follow conclusions drawn from morphologic evidence.Hence,the authors consider that these five spawning shoals,from Haichiao,Tachen,Niushan,Hsiungtitao and Chiehshih,belong to the same group,the so-called southern local population.They coexist in the same geographic district and are not completely isolated during spawning sea- sons.

    • EXPERIMENTS ON INTERCULTURE OF UNDARIA PINNATIFIDA(HARV)SUR.WITH LAMINARIA JAPONICA ARSCH

      1966, 3(2):119-129.

      Abstract (1838) HTML (0) PDF 769.43 K (1366) Comment (0) Favorites

      Abstract:1.Experiments were conducted at Shantung Marine Cultivation Station, 1963,on the interculture of Undaria pinnatifida(Harv.)Sur.on the bamboo rafts used primarily for the cultivation of Laminaria japonica Arsch.It was proved that the method of interculture was successful in the increase of pro- duction. 2.It was reported that for a short period of 60 days'interculture,the influence to Laminaria's growth was very slight and temporary,and it was possible to produce 850 kgs.of Undaria,about equivalent to 17% of Laminaria per mou. 3.In the event of extending the intercultural period to 80 days,the yield of Undaria could be increased to 1,000~1,200 kgs.,about equivalent to 20~24% of Laminaria per mou.Although the extension of time somewhat hindered the growth of Laminaria,yet one month after the harvest of Undaria, normal growth would soon be recovered. 4.It was concluded that the intercultural method provided a favorable means for developing commercial cultivation of Undaria,inasmuch as its ex- clusive culture was not considered to be economical.

    • A PRELIMINARY STUDY ON ARTIFICIAL CULTIVATION OF SPATS OF MACTRA ANTIQUATA SPENGLER

      1966, 3(2):130-139.

      Abstract (2296) HTML (0) PDF 756.37 K (1481) Comment (0) Favorites

      Abstract:1.The present paper deals with the artificial fertilization,embryonic de- velopment,metamorphosis and the process of settlement,with special refer- ence to the living habitat of larvae and the artificial rearing of spat,of a com- mon edible clam—Mactra antiquata Spengler. 2.Ripe eggs of superior quality can be obtained by means of collecting eggs through dissection and by washing and settling eggs.Immediately after fertilization,it is necessary to renew fresh seawater,to wash off surplus sper- matozoa and unfertilized eggs,and to keep the developing embryos in a sus- pended condition.Under the favorable environment,the hatching rate can rea- ch as high as 95%,or even higher. 3.The range of favorable temperature for the embryonic development lies between 17~24℃,the most favorable temperature being 20~24℃. 4.The range of favorable salinity for early development,i.e.from fert- ilization of eggs to blastula stage,is closely related to that of adults.The ra- nge of salinity increases with larval development;but the range of favorable salinity for spats appears to be more restricted than for larvae. 5.Within the range of light intensity between 500~2500 lux,the trocho- phore larvae are markedly positive towards light,i.e.positive phototropic. The veliger larvae,on the other hand,are negatively phototropic,but not very marked. 6.The trochophore larvae show a definite reaction towards the color of light,being positive towards green,yellow and white light. 7.When the larvae are rearing outside the laboratory,the filtered sea- water(changed daily about half of the original amount)can fulfill the food requirements of larvae which are capable of developing normally through me- tamorphosis to the stage of attachment. 8.The chief enemies of larvae are certain bacteria and carnivorous pro- tozoans which can be kept under control by changing water constantly,so as to keep the culture-medium clean.The rate of survival of larvae will be enha- nced by taking such measures. 9.Within the range of favorable temperature the larvae require 11~13 days to complete the development from the straight-hinged larvae to the sta- ge of settement.It is possible to accelerate the growth-rate of larvae by rais- ing the temperature. 10.The size of newly-hatched larvae lies between 208 X 189~225 X 209μ. They attach to the substratum by secreting byssus.The larvae under 1 mm. in body-length have,however,no strong desire for settlement. 11.The larvae under 1~2 mm.in body-length begin to lead a more sta- ble life of settlement.Those inhabiting the fine sand are growing faster than those inhabiting the soft mud;whilst those without the means of settlement are growing slowest.

    • >RESEARCH NOTES
    • MEASUREMENTS OF THE INDIVIDUAL WEIGHT OF PLANKTON IN PO-HAI AND YELLOW SEA

      1966, 3(2):142-149.

      Abstract (2034) HTML (0) PDF 1.18 M (1554) Comment (0) Favorites

      Abstract:Plankton samples were collected in 1960~1963 from Po-hai and Yellow Sea for the purpose of studying mainly the marine zooplankton and the feeding habits of economic marine fishes.The individual weight of those species of zoo- plankton and a few species of diatoms which might serve as food for economic fishes had been measured in various seasons and at different stages of develop- ment(or at different lengths).Species more than 0.5 mm.in size were mea- sured by weight.Those less than 0.5 mm.were measured by volume and then the avearage volume multiplied by the specific gravity(1.04).Ten groups of zooplankton were measured,including 27 species,10 kinds of larvae,2 kinds of eggs and 4 species of Coscinodiscus(Tabs.1~5). The results of the individual weight measurements of zooplankton in Po- hai and the Yellow Sea showed that:(1)The female is always larger in size and heavier in weight than the male in all species.(2)There exists a marked seasonal variation in individual weight of zooplankton,i.e.the largest in wei- ght always appeared in winter(Dec.-Feb.),the medium in spring(March- May),and the smallest in summer(June-Aug.)and autumn(Sept.-Nov.).

    • ON THE BIOLOGY OF CYPRINUS PELLEGRINI IN TWO LAKES OF YUNNAN

      1966, 3(2):150-155.

      Abstract (1959) HTML (0) PDF 333.02 K (1431) Comment (0) Favorites

      Abstract:Cyprinus pellegrini Tchang is an important food in both Singyun Lake and Chiloo Lake,attaining some 70% and 30% of the total yields of these lakes respectively.In this paper,the results of the biological study and the situa- tion of intraspecific differentiation of this fish in these lakes are presented. Age determination has been made on scales,the annuli being demarcated by intersection of the adjacent bands of circuli.Actual measurements of the body lengths and weights for various ages and the calculated boty lengths from scale reading are given.The fish measure on average 135 mm in body-length when one year old,197 mm,242 mm,and 288 mm when 2-year old to 4-year old of age respectively. The length-weight relationship of Cyprinus pellegrini of Singyun Lake can be expressed by the equation W=0.00001283L(3.0917),and that of Chiloo Lake, by W=0.00002181L(2.9875).Graphic representation of these two equations indi- cates that with the lengths being the same,the fish of Chiloo Lake possesses a greater body weight. This fish partly attain maturity when 1-year old and all are mature at 2- years of age.The breeding season of this fish in both lakes extends from April to September,but most individuals lay eggs in May and June.The eggs are adhesive,and are usually deposited on higher aquatic plants. Food studies based on contents of digestive tracts show that this fish is a zooplankton feeder.It feeds chiefly on cladocerans and copepods. Analysis of body-length composition of five catches,comprising nearly 2000 individuals,points to the preponderance of 1-year old and 2-year old age groups, individuals of more advanced age being rare in the catches.This leads us to think that the stock is on the way of diminishing as an effect of intentive fishing. Suggestion with regard to fishery management in these lakes is proposed.

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