1999, 23(4).
Abstract:RAPD was employed to assess the genet ic variations among 6 Eriocheir sinensis and Eriocheir japonicus populat ions distributed in Liaohe, Yellow , Yangtze, Oujiang, Pearl and Nanliu River systems. ( 1) Two primers could amplify distinct ive bands in 48 polymorphic 10- mer primers. The 880bp band amplified by primer Z2 was characterized only by Pearl and Nanliu River populations, and the 700bp band was characterized only by Yangt ze, Yellow, Liaohe and Oujiang River populations, both bands can be used as fingerprint ing marker to identify E. sinensis and E. japonicus . (2) The frequency of 947bp band amplified by primer Opp17 declined from south to north, e. g. , Yangtze River population ( 87. 50%) , Yellow River population ( 41. 66% ) and Liaohe River population ( 10. 83% ) . ( 3) The average genetic similarity index within each population ranked as Liaohe River 0. 908> Nanliu River 0 . 897 > Oujiang River and Pearl River 0. 895 > Yellow River 0. 890> Yantze River 0. 850. The genetic distances and their UPGMA and NJ dendrogram of six populations indicated that there was an obvious divergence between Pearl River, Nanliu River populations in southern China and Liaohe River, Yellow River and Yangtze River populations in northern China.
1999, 23(4).
Abstract:Biochemical genetic differences of two varieties of mitten crabs ( Eriocheir sinensis and Eriocheir jap onicus) from Liaohe, Huanghe, Changjiang, Oujiang, Pearl and Nanliujiang rivers in the mainland of China were analysed by acrylamide gel electrophoresis. The results showed: ( 1) There were no significant differences in biochemical genetic character of the mitten crab among Liaohe, Huanghe, Changjiang and Oujiang rivers, the genetic divergence among these four populations ( D = 0. 0006~ 0. 0053) were low and they all belong to populations of E . sinensis . ( 2) There was also no significant difference in biochemical genetic character of the mitten crab ( Eriocheir japonicus ) f rom Pearl and Nanliujiang rivers, the genetic distance was 0. 0007, which was lower than the genet ic divergence value at subspecies level. ( 3) There were significant dif ferences in the phenotype of SOD in the liver of the mitten crab between Liaohe, Huanghe, Changjiang, Oujiang rivers and Pearl, Nanliujiang rivers, where SOD - 2 was only found in the mitten crab of Liaohe, Huanghe, Changjiang , Oujiang rivers, while SOD- 4 was only found in the mitten crab of Pearl and Nanliujiang rivers, which could be used as biochemical genetic markers to differentiate these two groups of the mitten crab. The genetic distances between these two groups of the mitten crab were 0. 0721~ 0. 0747. ( 4) Dendrogram constructed by the genet ic distances among six populations of the mitten crab showed that there were two dif ferent clads. The northern clad was composed of the mitten crab ( Eriocheir sinensis) from Liaohe, Huanghe, Changjiang and Oujiang rivers, the southern clad consisted in the mitten crab ( Eriocheir japonicus ) from Pearl and Nanliujiang rivers.
1999, 23(4).
Abstract:Based on 32 morphological characters of each mitten crab( Eriocheir sinensis or E . j aponicus) from six rivers, Liaohe, Huanghe, Yangtze, Oujiang, Pearl and Nanliujiang, Cluster analysis and discriminant analysis were conducted. In the result of cluster analysis, crabs from northern rivers, Liaohe, Huanghe, Yangtze and Oujiang were pooled into one group as E. sinensis, while crabs f rom southern rivers, Pearl and Nanliujiang were pooled into another group as E. japonicus . In discriminant analysis, crabs of northern rivers could be divided from southern rivers automatically, and the accuracy rate of discriminat ion was 100%. Mean accuracy rate of discrimination on crabs f rom northern rivers, Liaohe, Huanghe, Yangtze and Oujiang, was 86% . Yangtze was the lowest, 73% , while Huanghe was the highest, 97% . Mean accuracy rate of discrimination on crabs from southern rivers, Pearl and Nanliujiang, was 95%, Nanliujiang was 96% , Pearl was 94% . ANOVA was conducted on parameters highly contributed to distinguish the populations of mitten crab, and coefficients of difference were calculated. According to Mayr ( 1953) 75% rule, in this paper the results indicated that difference between crabs from northern and southern rivers was greater than difference between subspecies, while dif ference between crabs of four northern rivers and between crabs of two southern rivers belong to of population level.
1999, 23(4).
Abstract:An expert system for fish stock assessment was designed and developed by using the Objective Knowledge Process System (OKPS) as the development tool based on the fish stock assessment models and expert knowledge in this field .The stock sizes and catchable yields for hairtail , chub mackerel and filefish in the East China Sea can be estimated by the expert system.
1999, 23(4).
Abstract:Two enclosure experiments were carried out from June to October in 1995 and June to August in 1996 to evaluate the effect of different types of monoculture or polyculture on water chemistry in enclosures .The results showed that concentration of total nitrogen and total phosphorus , chemical oxygen demand , and salinity increased before rainy season then dropped rapidly after rain . When only feed was adopted , the concentration of reactive phosphate and total phosphorus was relatively low and the concentration of nitrite , nitrate , ammonia and total nitrogen was high .When both feed and fertilizer was provided , the concentration of nitrite , nitrate , ammonia and total nitrogen was low and the concentration of reactive phosphate and total phosphorus was high .Concentration of reactive phosphate was usually higher in enclosures stocked with hybrid tilapia , Oreochromis mossambicus ×O .niloticus , while the concentration of ammonia was higher in enclosures stocked with Ruditapes philippinarum or Sinonvacula constricta .Chemical oxygen demand in present experiments was not as high as that usually reported in freshwater fishponds or seawater shrimp-ponds , and much lower in those enclosures stocked with bivalves .Present experiments suggest that water chemistry in experimental enclosures was mainly dependent on daily management activities such as feeding and fertilizing , and partly influenced by stocked shrimp , tilapia and bivalves at the same time .
1999, 23(4).
Abstract:Metabolism of bacterial carbon in shrimp cultural enclosure ecosystems was studied from June 6 to August 24 , 1997 in the shrimp farm of Huanghai Fisheries Group Corporation .The results were :the average rates of respiration , production and detritus decomposition (μgC/L·d)of bacterioplankton were 349 ±167 , 180 ±86 and 529 ±253 respectively .The bacterioplankton respiration was 40 percent of the plankton community respiration .The rates of respiration , production and detritus decomposition (μgC/L·d)of sediment bacteria were 168 .07 , 72 .27 and 240 .34 respectively .There were significant correlation between the sediment respiration and the sediment temperature , bacteria biomass and organic carbon concentration .The respiration rate of certain numbers of sediment bacteria showed significant negative correlation with total sediment bacteria biomass , which proved that the metabolism of the sediment bacteria was probably limited by inadequate substrate supply .The respiration , production and detritus decomposition of the bacterioplankton were 2 .08 , 2 .49 and 2 .20 times higher than that of the sediment bacteria in the cultural period .The bacterioplankton and sediment bacteria decomposed 30 percent of the organic carbon income of the enclosure in total , in which , 10 percent was transformed into bacterial carbon and 20 percent was mineralized .
1999, 23(4).
Abstract:In winter of 1995, the concentrat ion of total organic carbon ( TC ) , total nitrogen ( TN) , total phosphorus ( TP) and pH in bottom sediments of each of four, 11- , 16- , 13- yr- old shrimp ponds in Qingdao of China were determined and the vertical distribution of them was studied. The results showed that the concentrations of TOC and TN in bottom sediment were increased with pond age, polluting depth were 20- 30 cm for clay soil, were 40 cm for silt . The pollution of surface sediment is more serious than that of deep sediment, and pollution of surface sediment of clay soil is more serious than that of silt soil. The concentrations of TP in bottom sediment were decreased with pond age, so that TP was absent. The depth of disturbed layer of TP was equal to the depth of polluted layer of TOC and TN. The pH of bottom sediment does not have regular change.
1999, 23(4).
Abstract:The experiments were conducted to research biofilter' s purifying ability .Several water quality indexes were tested in Eriocheir sinenisis' s larvae rearing pond to know the treatment effect .Compared with other treatment methods in traditional breeding , biofilter is more efficient in water purification .The removal rate of COD was 55 .5 %, the removal rate of ammonia-N was 33 .2 %. During the breeding process , pH was stable and DO was abundant .There were no DO debt and stink in rearing pond .
1999, 23(4).
Abstract:It was approached that the immune response of soft-shelled turtle , Trionyx sinensis , was influenced by its age , size and nutrition .The response of 2 years old turtle against bacteria T3was enhanced with the size increasing , especially when the weight was below 40g .In contrast , this phenomenon was not found in 1 year old turtle and its response was fluctuated on a lower or medium level .At the same weight the immune response of 2 years old turtle against T3 was much stronger than that of 1 year turtle .However , the response was weakened at a certain degree in the undernourishment .
1999, 23(4).
Abstract:The Bacterial pathogens were isolated from the diseased Eriocheir sinensis , which were cultured in the ponds in Shanghai Municipality and Jiangsu Province .The main symptom of diseased Eriocheir sinensis was the appearance of ascites in its abdominal cavity .By the experiments of artificial infection , physiology and biochemistry , the pathogens were identified as Aeromonas hydrophila and Vibrio mimicus .The results of drug sensitivity tests showed that Ciprofloxacin , Norfloxacin and Chloramphenicol were the most sensitive drugs .
1999, 23(4).
Abstract:A fundamental pattern was proposed for the fast autolysis of shrimp ( Metapenacus enisi ) tissues through a series of study on factors of UV radiation, mineral ions, pH value and temperature for autolysis. The speed of autolysis was accelerated by appropriate UV radiation and sodium ions under the pH value of 7. 0- 7. 5 with a gradient temperature from 40 e to 65 e at 5 e / 30 min. The rate of hydrolysis for shrimp protein was more than 80% under the opt imal conditions mentioned above.
1999, 23(4).
Abstract:The nutritional components of four kinds of shell meat from different species of pearl shell in South China Sea were studied and then compared with those of Ostrea rivularis and Mytilus edulis for evaluation in nutrition .The results indicated that crude protein contents in four samples were of 78 .97 %~ 83 .64 %, 81 .38 % in average , and the score of amino acids in protein ranged from 81 to 94 , in which MET and CYS were limited amino acids .Crude fat of the samples was of 2 .68 %~ 6 . 31 %,4 .41 % in average .The average total of C20∶5(EPA)and C22∶6(DHA)in fat was 33 .70 %. Minerals in the samples were rich , particularly in Ca , P and Zn contents .As to vitamin contents in the samples , they were in general quantity .therefore , the nutritional value of pearl shell meat highly exceeded that of Mytilus edulis , but some of nutrients were superior to those of Ostrea rivularis .In conclusion , pearl shell meat can be considered to be good natural sources for healthy food production .
1999, 23(4).
Abstract:Based on the intrinsic crystal structure and physical and chemical properties of pearl , a new technique for bleaching and brightening pearls by means of comprehensive mechanism of adsorptive and oxidative bleaching and fluoreseering was proposed in this paper .The technique can be used to bleach colored or faded pearls and make them glittering and lustering .The bleached pearls might keep their glittering for a long period of time .No scraps were scraped off from the pearl surface . This process is simple , efficient and practicable .The liquid agents for bleaching are formulated uniquely and scientifically .It is also applicable to shape-like pearls and shell-pitted pearls .
1999, 23(4).
Abstract: