Abstract:The cultivation of purple laver in Guangdong province was started in September,1966. The conchocelis of Porphyra haitanensis T. J. Chang et B. F. Zheng wereintroduced from Fujian province and their thallus were cultivated following spore-collecting. Guangdong province is situated in the subtropics region, the harvest scasonof P. haitanensis is very short and the yield is low. Since a well adaptable species isnecessary to select several species of purple lavers from different regions of Guangdongcoast were collected and cultivated in January, 1974. During the period of cultivationtill the spring of 1977 the experiment had shown that P. guangdongensis adapted tohigher temperature better than P. haitanensis. During Novermber, 1978 to January, 1979 some measurements of respirationwere made and the results had shown that the rates of O₂consumption, CO₂releasedand the respiratory quotients of P. haitanensis were much higher than those of P.guangdongensis at the same temperature. Especially at 25℃ the differences of the ratesof O₂consumption and CO₂releasing for both species were very significant(ρ0.001). During December, 1979 to January, 1980 the rates of photosynthesis for bothspecies under different temperature were also measured. The experiment showed thatof P. guangdongensis at 30℃ (19.53μl O₂/mg d. w./h)and P. haitanensis at 23℃ (20μlO₂/mg d. w./h.) the rate of photosynthesis reached to maximum. While the raise ofwater temperature the rates of photosynthesis decreased. The ration of photosynthesis and respiration of P. guangdongensis were higherthan that of P. haitanensis within the temperature range of 25-33℃. The data fromindoor experiments agreed with the results of outdoor cultivation. P. guangdongensis is recognized to be better adapted to higher temperature and having faster growththan P. haitanensis

Abstract:In generally , to make sure of sperm enter into lii ing egg zs considerable coif-ficult. V he got eeellent obserations by use of the elot.roni scanning microsenpe.he results pan be summarised as follows: 1.intured egg he bream 3legaLobru·mrc G-minrrbds Riehardsun is snrru-ended hr the thick chorion. There is : Panel-Iike depression on the chorion nearbythe nnim,l pole. L miorupyle is at tha haftzn of tho depression. L nicrupylar tubr,5 dia.n ieier, c;onnels the ruicrupyle into the protoplasmic gerruirzal disL. I heaerosomles sperm cont:zct vth tbc egg rytaplasm through this nlicropylar tube. Inzddition, tliere are numerous infinitesimal pares arc found all over the surface ofrh.)rion. 2 .he spna oI the breanz enter into tho egg instantly, and all mioropylar t.nhesare sealed by the fertilised ping ithin 30 seconds after insemizicztion, the sherzn entrzsthc cgl; and cxst the flagellum. 3. tllthough only one sperm is alloned to enter into tho egg not·lolly，but agreat quntity of super auizzerary sperms is eoessfrry to raise the rate of ert ilition.Hone-er, more than one sperm enters into the egg, the number of chronosrunill he riscd than the normal axxd cause abortion early enahrogeneaia, thus aferfed plug is Formed at the inner openhg of the micropylar tube.

Abstract:The ratios of mannuronic acid (M) to guluronic acid (G) of sodium alginatesextracted from 9 species of brown seaweeds, Sargassums and Laminariea, collectedalong the coast of China, were determined. Among them, Sargassum siliquastrum andS. henslowianum have higher content of G and lower M/G ratios of about 1, and La-minaria has higher content of M and higher M/G ratio of 2. The M/G ratios are lowered from 1.13 in the original alginate to 0.16 in thefractionation product after oxalic acid hydrolysis for S. siliquastrum, from 0.82 to0.14 for S. henslowianum and from 2.01 to 0.09 for Laminaria. But those of thefractionation products by MgCl_2-EtOH precipitation are less lowered. The average molecular weight and degree of polymerization of the sodiumalginates tested are generally decreased after oxalic acid hydrolysis to about 2,000 and10, respectively. The inhibition efficiencies of sodium alginates from differient species of brownseaweeds prior and after oxalic acid hydrolysis on the absorption of ⁸⁵Sr in the gastro-intestinal duct of rat indicate that the sodium alginate from Sargassum siliquastrumgives the best efficiency, enhancing from 66% prior hydrolysis to 78% after hydro-lysis, followed by that from S. henslowianum, incroasing from 56% to 64% and by that from Laminaria, from 27% to 56%, respectively. The inhibition efficiency of sodium alginate from S. siliquastrum on the absor-ption of a mixture of ¹⁸³Ba, ⁸⁵Sr and ⁴⁷Ca indicates that it is remarkably effective on¹⁸³Ba, increasing from 14% before hydrolysis to 77% after oxalic acid hyrolysis.

Abstract:This paper deals with the physical and chemical characteristics of two highlyproductive small lakes in the suburbs of Wuhan Shi in 1973. Some regularitiesconcerning the relationship botween these characterstics and the richness of thenatural food resources are recorded. In connection with the problems that arise fromthe fish farming, special investigations are made with respect to some of the quantita-tive indexes for the adequancy of the water fertility in the small lakes. Relavantequations are proposed. The essential analytical records are concluded as follows: 1. During the fish farming seasons, the quantity of dissolved oxygen is generallyfound to be 7mg/l. The oxygen content at the bottom layer is usually lower thanthat at the surface. 2. A proportion exists between the total nitrogen and the amount of ammonia.The sensonal fluctuation of the total phosphorus is similar to that of the nitrogen. Aquantitative relationship also exists between the amount of phosphate and the totalphosphorus. 3. The quantity of the aquatic micro-organisms decreases geometrically as thewater temperature rises. 4. There is a high density of phytoplankton, which has a lagged effoct on theutilization of nitrogen. It also bears a quantitative relationship with the change of theratio of nitrogen to phosphate. When the water blooming occurs and the nitrogencontent reaching to a sufficient concentration, the N/P is about 10-17. 5. There are also large amount of protozoa and rotatoria, and the seasonalfluctuations of their standing crops are directly related to the total phosphate content.Crustacea ns are few in species and low in quantity, and shows no clear relationshipto the nitrogen content. 6. The biomass of zoobenthos is quite low. There are only a few aquatic oligo-chaetes and chironomid larvae. No molluscs are found- 7. When the total nitrogen content is 6-8mg/l it denotes that the fertility ofthe water reaches to the critical value. 8. While a decreases of 1 mg/l of dissolved oxygen at the surface layer, it meansa decrease of 1.35mg/l at bottom laryer. So that when the amount of dissolved oxygenat the surface is as low as 2 mg/l, the oxygen of the bottom layer will be completelyexhausted lack of oxygen.

Abstract:The fertilized eggs of Sinilabeo decorus lungting had been obtained by artificialfertilization. Eggs were hatched in 3 different temperatures or 20℃, 25℃ and 30℃each with 100 eggs. The experiment was repeated 3 times and the results are sum-marized as follows. The development of the embryo are quite similar to that of other domestic carps-The embryo of this fish is rather sensitive to the change of water temperatures, theexperiment reveals that suitable temperature for hatching is 18-23℃ and 20℃ beingthe optimum. The rate of embryonic abnormality is rather high in this fish oven at the optimum temperature 20℃, there are still 20-35.2% abnormal embryoesproduced. The occurence of abnormalities whether it is a genetic defect of this fish orit is due to the external factors remains unknown.

Abstract:Qingfengmycin is an antibiotic produced by Streptomyces qingfengmyceticus.The antibiotic can inhibit the growth of Myxobacteria and thus it can be used as a fineprophylactic and therapcutical agent for gill-rot fish disease infected by pathogenicMyxobacteria on black carp (Mylopharyngodon piceus) and grass carp (Ctenopharyn-godon idellus). The better way of treatment is to feed the sick fishes with theantibiotic mixed with food. The therapeutical dosage of qingfnegmycin for adult fish was 2.5 million unitsper 50 kilogram body weight daily. The recovery rate was 95% when the drug wasapplied succesively for three days. For young fish a dosage of 5 million units per 50kilogram body weight was applied and the recovery rate was 72.7%. If both adult andyoung fish were given a prophylactic treatment with the antibiotic before the epidemicseason it was found that the mortality of the treated adult fish was 1% while 27% inthe control. The mortality of the treated young fish wag 15.7% while 40.3% in thecontrol. Qingfengmycin can be produced by conventional solid fermentation method.Morever, the material which used as culture medium for the Streptomyces can also beused as additional fish food. The antibiotic is non-toxic and inexpensive.

Abstract:By manuring to reproduce food organisms in the pond of mullet fry in order toraise survival rate of the fry has been successful. 648，462 fingerlings of 23.2---49.83nm in 1980 and 426,902 fingerlings of 25.45-27.85 nzm in 1981.were ubt,ined. The method of spxead maxzure cultivates suitable sire of living feud for the mulletfry. Froth the species axed quantity can he enough to meet the needs of fbe fry duringthe larvae and fingerling stages. Tho feeding habits of mullet a.rc shanged with growth. At the body length heluw2t1 rnm. they mainly Feed on ooplanhtum; the body length between 20-6q nim，theirfeed arc oohenthos and benthie. algae; body leagt.h m er 60 mm, their feed are mainlybenthic algae. The growth of mullet fry is elosaly related with the azuount of foodsupply in the pond.

Abstract:The oxygen consumption of different size Tilapia nilotica were measured andstudied under temperatures ranging from 21℃ to 26.5℃, within 24 hours in succession.The results are summarized as follows: At body weight 0.00306 kg, it is 250.76mg/kg/hr at temperaturo of 24℃; attwo-month old, body weight 0.04053 kg and 0.04289 kg, it is 136.58mg/kg/hr and154.48 mg/kg/hr respectively at 24℃; at three and half-month old, body weight0.07150 kg, it is 91.61 mg/kg/hr at 21℃; at fifteen-month old, body weight0.23300 kg and 0.43330kg, it is 67.90mg/kg/hr and 123.10mg/kg/hr respectivelyat 22.5℃ and 26.5℃; at twentyfour-month old, body weight 0.47200 kg and0.56830kg, it is 88.58mg/kg/hr and 111.58 mg/kg/hr at 22.5℃ and 26.5℃respectively. The experiments show that oxygen consumption of T. nilotica decreases as the ageor the body weight increases. This indicates that the younger fish require higheroxygen consumption than do the older ones, and the rate of oxygen consumption ofthe fish increases as the water temperature rises. The rates of oxygen consumption between the male and the female T. nilotica areshows no significant difference at the same size and same water temperature. The fish can survive in very low oxygen content waters, and its the asphyxiatingpoint is 0.07-0.23 mg/l.

Abstract:The seasonal variation of laminaran content in Sargassum hornori collected monthly from October. 1974 to March, 1975. The investigation reveals that thereis no laminaran in October. The content gradually increased from November until itreached a maximum of 4.32% in March of the next year. Dried seaweeds are extracted with a dilute HCl solution. The laminaran was isol-ated and purified by the mothod of frantional precipitation with alcohol. Laminaran was sulfated in formamide with chlorosulphonic acid. The optimumsulphating temperature and treating times were found to be at 35℃ and for 45 min.The resultant Na laminaran sulfate contains about 20% S.

Abstract:The Plasma-membrane of the Porphyra conchocelis cells are found to be rail-likeand three layered structure of plasma-membrane. An invagination is found on theplasma-membrane of the swollen cell. The nutrients can be engulfed by the invagination of plasma-membrane from ano-ther swollen cell through small hole. Granular substance is found to be surrounded by the plasma-membrane invagina-tion formming a phagocytic vacuoles finally.

Abstract:The field work of this survey was carried on from April to July 1981 duringthe breeding season of the "Four famous chinese carps" (Ctenopharyngodon idellus,Mylopharyngodon piceus, Hypophthalmichthys molitrix and Aristichthys nobilis). The results show that the locations of the spawning grounds of these fishes alongthe up and middle sections of the main stream of the Changjiang River is similar tothe work which was made in 1960s. In 1981, the total amount of the eggs spawned bythe four domestic fishes in the whole surveyed sections of the river is estimatedto be 173 hundred millions. It is only about 15.7% of that in 1960s, and indicatesthat the resources of these fishes in this river has been critically declined. At present, the proportion of the eggs spawned by these fishes in the ChangjiangRiver make a great difference in comparison with that in sixties. In the whole inves-tigated sections of the river, the egg's percentage of C. idellus is 59.8%, M. piceus,31.6%, A. nobilis, 4.7% and H. molitrix, 3.9% in 1981. But in the sixties, the egg'spercentage of C. idelllus is 40.9%, M. piceus, 26.1%, Ⅱ. molitrix, 26.1% and A.nobilis, 6.9%. The changes are remarkable. The structure of reproduction populations of these fishes in the Changjiang Riverhas been presented in simplification (or destruction). It appears as follows in the repro-duction populations: the body-size of parent fishes becomes smaller in common, thenumber of age-groups is reduced, the low-age-fishes appeare to be a dominant and theprimary sex-matured fishes constitute the majority. All of these are the obvious sym-bols of the declination of the resources. The investigation indicates that the resources of these fishes in the ChangjiangRiver has been seriously damaged and the total amount of the eggs spawned by thesefishes has sharply decreased. For the purpose to recover the natural resources or these fishes in the ChangjiangRiver, it is necessary to protect the natural reproduction conditions and rebuild themigration pathway and breeding places of these fishes. Seeing that the migratorypathway has been cut off by the water project at Gezhouba, we propose that thefacilities for a fish passage should be built on the dam.