| This paper compares the mature Eriocheir sinensis in the Yangtze estuarymigratory groups with their breeding discriminant. It also investigate the matureEriocheir sinensis in the Yangtze estuary on their distribution, migration routes,migration speed, and the spawning ground near Jiuduansha wetland by surveys andmarking and releasing experiments. We study the mature Eriocheir sinensis in theYangtze estuary to provide theoretical references for environmental protection of themature Eriocheir sinensis as well as value-added discharge and impact assessment.is1The morphological difference analysis between the migratory population andthe cultured population of Eriocheir sinensis of the Yangtze RiverThe morphological discriminant analysis between the migratory and the culturedpopulation of Eriocheir sinensis were studied. Thirty-eight morphological metricparameters were evaluated through the methods of discriminant analysis and analysisof variance. Discriminant analysis was separately used for males and females of thetwo populations, and as a result, two groups of five parameters were selected out. Thentwo discriminant functions for males and females were separately established withthese parameters. The fitted probability of male and female crabs is94%and92%through these functions, and the discriminant efficiency of the migratory population isbetter than the cultured population. The result of analysis of variance shows that therewere sixteen morphological parameters were significant different (P<0.05) between thetwo populations, and eight of them were extremely significant different (P<0.01). Themain morphological parameters of discriminating the two groups are the ratios of thefrontal teeth space length and the fourth foot knuckle length with shell width (L2/Wand F44/W). These differences reveal that the migratory population of Eriocheirsinensis is more suitable for long-distance swimming, and the two populations can beclearly distinguished in the normal practice.2Research on the migration, distribution and spawning grounds of Eriocheirsinensis of the Yangtze River.The migration routes, speed, distribution of the mature Eriocheir sinensis near thenorth-south Estuary trough inYangtze River and the spawning grounds near Jiuduanshaare studied in the method of survey monitoring and marking technologies. The fishing peak of the Eriocheir sinensis in2010near Jiuduansha wetland wasbetween November25th and December3th. The weight of the mature crabs is115.83±50.63g, the shell width was60.94±8.78mm and the shell length was56.15±7.79mm. The size of the crabs was smaller than the crabs between1989and1999of the Yangtze River, and also smaller than those between1997and2005. Thespawning ground of the mature Eriocheir sinensis is investigated preliminarily. Therange of the spawning ground of Nancao is from121°49′E to122°13′E, and theBeicao’s spawning ground is form122°0′E to122°13′E. The number of the matureEriocheir sinensis of the Nancao is more than the Beicao’s. After stocking for143days,the retention ratio of the label tag was72.22%, and the retention of the ringlike tag was99.54%. It proved that ringlike is more suitable for releasing activity which lasts longer.The results will provide theoretical references for environmental protection androcovery and the marking methods of the mature Eriocheir sinensis.3The physiology adaption of the mature Eriocheir sinensis to the environment ofthe Yangtze estuary after stockingThis study investigated the physiology adaption of the mature Eriocheir sinensisto the environment of the Yangtze estuary after stocking by tagging method. Thirtythousand mature crabs were released in the Yangtze estuary on December23,2010,and five thousand of which were tagged both by the label tag and the ringlike tag. Thefishing tools of the recapture were1.5-meter-high fishing nets, whose mesh size was10cm2. The daily fishing time depended on the ebb tide time of the Yangtze estuary,and the fishing mesh was pulled up at the end of the ebb in the daytime.Simultaneously, the data was recorded, which included the number of the crabs and thetemperature, the salinity pH and the dissolved oxygen of the water and so on. Wetested and recorded some physiological and biochemical indices of the hepatopancreasand the serum of the crabs before and after stocking, which were recaptured indifferent days. If the crabs’ number of the same day and place more than20, weselected20crabs randomly as the samples to test the indices. However, if the numberis less than20, all the crabs were selected. To reduce the impact to the indices, whichwas made by the complex environments of Yangtze estuary, the samples of the crabsthat were captured in the similar area was selected out and divided into6groupsaccording the captured day. And set the samples of the carbs before stocking as thecontrol group. There were7groups in the experiment, which were0d,6d,9d,13d,22d, 70d, and79d group. Then compared and analyzed the data with SPSS statistic software.The result showed that the indices had some changes after the crabs being released.After having been released for6days, the activities of superoxide dismutase (SOD)and the catalase (CAT) in the hepatopancreas and the concentration of the triglyceride(TG) and the hemocyanin in the serum of the mature crabs were reduced on the6th dayafter. And then three days later, the SOD, CAT activities and TG concentration of themature crabs all declined to a very low level. And at this time, the SOD activity andTG concentration of the mature crabs were significantly different with those beforestocking (P<0.05). After stocking, the activity of acid phosphatase (ACP) in thehepatopancreas and the activities (or concentrations) of alanine aminotransferase(ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), hemocyanin,total protein (TP), albumin (ALB), total cholesterol (TC), creatinine (CREA) in theserum of the mature crabs all increased first and then declined broadly. On the79th dayafter stocking, the SOD, CAT, ACP activities in the hepatopancreas and the ALP, ALT,AST activities in the serum of the mature crabs all resumed to a similar level withthose before being released (P>0.05). However, the TP, hemocyanin, ALB, TC, TG,CREA activities in the serum were significantly lower than those before stocking(P<0.05). Through the research, we found that the mature Eriocheir sinensis had seriesof reaction after stocking, such as the immunity declined and the metabolism enhanced.The metabolism and the function of the organs and tissues of the mature crabs wereresumed step by step after having been released for22days. And they all reached thesimilar level with those of the crabs before stocking on the70th day. The result showedthat it may take the mature crabs22days to adapt the environment of the Yangtzeestuary. In order to strengthen the environmental adaptability and the stockenhancement effect of the Eriocheir sinensis, good nutrition diets and relatedenvironmental acclimation should be provided. |
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