Abstract:The short-snout ice--fish, Neosalanx tangkahkeii taihuensis Chen, is one of commer- cial fishes in lake Taihu. In the autumn of 1975 we carried out experiments in artificialfertilization and hatching of the fish in Taihu. As a result, we obtained 543 prelarvaeand 465 samples of the developing eggs. According to our experimental studies, it is proposed that the period from Octo-ber eighth to twenty--fourth may best be set as a prohibited period of fishing in order toprotect this fishery resource.

Abstract:This paper is written to assure that the water layers in Tsingtao district are suitable forthe growth of Porphyra yezoensis and Porphyra suborbioulata and to present references for abetter development and a higher production of Porphyra cultivation. The experiments werecarried out from December, 1963 to April, 1964, in the Middle Harbour (中港), Tsingtao. The results obtained are as follows: 1) Porphyra yezocnsis can grow extremely well from December to April in the followingyear. Their increase in volume in the course of 91 days, is from 0.54 cm² to 154.12 cm². 2) The water layers fitting them best in the littoral zone are 0.5-1.5 meter over thestandard level. In these layers they do not only show rapid growth but also show good colours.(The volume increase of plants growing two meters above the Standard level is, within 58days, only one-tenth of that growing one meter above the standard level). The growth of Por-phyra yezoensis is hindered. In the layers of two meters or more above the standard level. Th-eir pigments fade, they turn to be quite pale, and they die off in the end. 3) Porphyra yezoensis which have been growing in littoral zone and have been later tran-splanted into the sea water do not suffer any deterimental effect on their growth. And whatis more, they grow very well in an ever changing weather with no sunlight before the Mouthof March. It is the authors' finding that the layer which suits their growth best is the one thatlies between the surface water and 0.5 m. below. 4) The growth of Por phyra suborbiculcata in the littoral zone is the same as that of porphyrayezoensin.Porphyra suborbiculata growing two meters above the standard level is scarcely existing.The migration of Porphyra suborbioulata from the littoral zone into the sea water favours theirgrowth. The speed of growth becomes much faster. Based upon the experimental results, the authors hold that full attention should be paidto the growing layers of Porphyra duriug their cultivation in the littoral zone, and the authorsdeem it necessary that, in the time the cultivation in the littaral zone is going on. attentionshould also be given to the hanging method of their cultivation in a big scale. Although thegrowth of Porphyra in nature is confined in the littoral zone, it is not correct to considerthe surface layer to be unsuitable for their growth. It is shown by the experimental resultsthat Por phyra raised in the water layers from the surface to 0.5 meter below grow fairly well, especially before March and they over-match those cultivated in the littoral zone. This phe-nomenon is perhaps produced by the relatively stable surroundings , viz. appropriate conditionsof temperature and sunlight. The authors consider it to be desirable to raise Porphyra byhanging method at this depth. The cultivation by hanging method is particularly practicableto spread the cultivation areas. It can be practised in shallow waters which are unsuitablefor the cultivation of Laminaria. The cultivation of Porphyra by the hanging method is alsoan easy job.

Abstract:Feeding Experiments were designed to measure the growth of grass carp fingerlingswhen fed with different proportions of enzymatic fiber meal containing 10--12% crudeprotein, mixed with other ingredients. Fiber was obtained from the waste of the sugarand paper manufacture industries. Experiments on food nutrition of fingerlings werereplicated three times in six suspended 14 M² netcages, each stocked with 500--700 fin-gerlings, their weight ranging 2. 42--9. 90 gm. Results indicated that feeds containing60% enzymatic fiber could substitute for the cereals which had been used by the tradi-tional technique as staple food in fingering culture. Field experiments were conducted inthre 666 M³earthen ponds, each stocked with 3000 grass carp fingerlings for a periodof 103 days. The pellet, composed of 60% enzymatic fiber and other ingredients andcontaining 19. 15% crude protein level, yielded a 61. 8--116% increase in productionand saved 70% cereals as compared with the results secured in the control ponds in whichfingerlings were fed solely with cereals. Pellets of the same composition were used in anarea of 119 mu(1 mu = 666M²)to feed commercial-sized fishes,their weight averaging 500gm. The daily feed allowance approximated 1--2% the weight of the fish. The total fishyield after eight months was 62% higher than that of the previous year. Pdrotein requirements of the grass carp fingerlings: (1) the optimal protein level ofthe diet, determined by both methods of polynominal regression and parabolic curve,was found to be 22.77--27.66%. The protein effciency ratio decreased with the in-crease in protein content of the diet according to the formula, Y= 29.2786 -- 0. 52968 X;(2) carcass analyses by the paper-chromatography method revealed 18 amino acids.Growth proved to be satisfactory when the composition of the pellet diet contained theessential amino acids. The growth rate exhibited a negative relation with the content ofcellulose in the diet.

Abstract:A study has been made on the gonadal development and histological changes of thehypophysis in the mullet (Mugil soiuy Basilewsky) from three environments differingin salinity: seawater, freshwater ponds, and oligohalinous-water ponds (salinity2‰).The results of experiments on the induced spawning of mullet reared in freshwater andoligohalinous-water ponds are given, and some measures which might be effective ininduced spawing are suggested. Environmental salinity effects the relative size of the RPD (rostral pars distalis)and the PPD (proximal pars distalis). And the increase in size of the RPD is accompaniedby an decrease in size of the PPD. In mullets collected from freshwater and oligoha-linous-water ponds, the RPD is 61. 3% larger than that of fish collected from seawater.And the activity of prolactin-secreting cells is also stronger. On the other hand, the PPDof the former is 45. 8% smaller than the latter, and the gonadotrops are less active, asdemonstrated by staining reaction. The development of the oocytes of freshwater or oligohalinous water pond culturedmullets does not go beyond a point in between the early and the middle stage of phase IV. Only a few oocytes can develop to the middle stage (mean oocytes dismeter 780μ). Mostmullets in such a state failed to induce spawning. Only two females were successful ininducing spawning from which we obtained 34 and 17 larvae respectively that lived 17-48 houres. Male mullets cultured in freshwater or oligohalinous-water ponds may reachsexual maturity.

Abstract:The heat supply for the circulating air in tunnel driers of partial recirculatingwaste moist gas comprises of four heat comsumptions. (i. e. the sensible heat of exhaustgas, heat of evaporation, heat of elevation of materials and transport equipments, andthe heat loss during drying process). The temperature (t_c) and humidity (x₀) of mixinggas are calculated by means of corresponding equations with clear conception. The following suggestions are consulted with the aid of mathematical treatment: 1. The total heat supply calculated with other different methods can also be sum-marized into four similar terms. 2. The sensible heat and heat of evaporization either with dry or wet base are pro-ved to be perfectly identical with the real case. 3. The values obtained for the properties of air mixture from the tunnel drier bothby I-X chart and by calculation are in close agreements. 4. The choice of parameters of drying medium is considerably important in dryingprocesses design. Acompanying the velocity of drying medium, the teperature (t₂) andhumidity (x₂) of the exhaust moist gas are suggested as basic parameters.

Abstract:Two-boat trawl is generally in use for fishing prawn (Penaeus orientalis) at Po Haiarea in autumn. Po Hai is not only the main fishing ground for prawns, but is also thespawning and nursery ground of many commercial fishes. Unfortunately, a considerablenumber of young fishes have been destroyed in the prawn trawing every autumn. It is avery serious problem for the fish stock, so that, a new two-boat long square prawn trawlwas designed in 1974--1977, in order to increase catching efficiency and to reduce thedamage on young fishes. The characterstics of this newly designed trawl are: its square was twice as largeas that of the original one, the side panels were added to increase the covered net moutharea and the height of trawl, in order to prevent prawn in jumping over the headline ofthe net when they touc on the ground rope, and its cod-end mesh size was increased to50 mm. Consequently it saves a large quantity of young fishes from escape. The experimental results are satisfactory. In comparing with the old trawl model inwater tank, the principal advanges of new trawl model are the lower resistance, the higherheadline and the larger area of the covered mouth. The fishing operations have provedthat the eatching efficiency is increased over 40% and the damage to young fishes redu-ced over 60%.

Abstract:The present paper describes the many--years accumulated data of the growth rates;annual variations of surface and bottom water temperatures; the characteristics of watersystem distribution and the changes in inshore waters of Dong Hai and Huang Hai inSpring season since 1960. It has also disscussed the changes of the water tamperature in relation to the fisheries in these sea areas. There are specific the of the water temperature distribution in these sea areas inSpring season. In Huang IIai it is in the form of trough shape, the in Dong Hai it is inthe form of ridge shape. The water system of these sea areas is influenced very much bythe coastal cold water of Huang Hai, warm current of Taiwan, the fresh water currentfrom Chang Jiang and the cold water mass off the southeast coast of Qing Dao. The tem-perature changes and the variation of positions of them would greatly affect the tempera-ture statue and distribution of the whole sea area, and it seems one of the reasons that itleads the temperature distribution and variation of positions to be different each year. In combining with fishing operation, the variation and distribition of watertemperature is analysed in relation to the migration of fishes and the time of fishingseason. It is pointed out that investigation of water temperature distribution and changesin the fishing grounds is important in making fishery forecast. Some useful watertemperature indices are provided for fishery forecasting.

Abstract:The work was conducted during the growing season of fishes (from April to Octo-ber) in 1978, in Xiamen. The total number of fish studied was 1,596. The preliminary study indicated that the silver carp (Hypophthamichthy molitrix),the big head carp (Aristichthys nobilis) and the grass carp (Ctenopharyngoden idellus)all show the diural rhythm of feeding. The peak of feeding lies at 12:00--20:00. Thegrass carp usually retreats for a certain extent at 16: 00. Seasonally these three fishes takefood vigorously in July and August comparatively greater than in other months. By the method of daily average fullness index, the daily ration (the relation of thetotal weight of food taken in a day to the weight of tbe fish) is 36.2% for grass carp,11. 4% for silver carp and 6. 6% for big head carp, and the duration of feeding withina day is about 20 hours for the grass carp, and 18 hours for silver carp and big headcarp. The rhythm of feeding seems to be influenced by the following factors: the intensityof illumination, the amount of dissolved oxygen, and the temperature of the water. Illu-mination plays a very important role, both directly and indirectly, since it affeclswater temperiture and the amount of dissolved oxygen.

Abstract:The development of the digestive system of the Acipenser fry can be divided general-ly into three stages: 1. The early development stage. When the length of the fry is 12--21.5mm, theyolk sac is large, and the alimentary tract remains primitive. Then the mouth openingand four buds of barbels appear.The fry swims vertically. 2. The completion of the alimentary tract. At this stage the fry attains a length of 21.5--26mm. The mouth is active, provided with toothed jaws. The intestine, rectumand anus are finally differentiated. The fry swims in level. 3. At the completion of the digestive system. The body length of the fry attains to26. 5--30 mm. The oral cavity bears teeth, and the liver, pancreas and pyloric caeca, etc.differentiate to completion. The fry becomes bottom dwelling. The fish is typically carnivorous and bottom dwelling. The fish prefers to eat inver-tebrates, such as freshwater Oligochaetes, Chironomids, Oladocerans, Copepods, etc. Roti-fers and algae are seldom consumed. As the body length reaches 30--31. 5mm. the yolk is nearly absorbed, and the frybegins to take food

Abstract:The full grown mother of pearl ware used in the experiments of fertilization. Artifi-cial fertilization was operated in the 0. 07% ammonia sea water. High rate of fertilizationwould be obtained, when the water temperature is 25--29℃. The fertilized eggs developto trochophores in 5. 5 hrs., Under the water temperature of 28℃ and the specific gravityof 1. 0227. Twenty days later the larvae begin to be attached and turn to benthic habitat.The experiments indicate that Platymonas and yeast being used to feed the larvae seempreferable