Initial Study Of Motality And Life-history Strategy Of Wild Tanichthys Albonubes Population Based On Otolith Technology

Population ecology is the research which focuses on the quantity and distribution of a population and the mutual relationships between it and the abiltic factors in its habitats, as well as other populations. To understand the ecological characteristics of endangered populations is beneficial to the research of social behaviors, life-history evolution and even the endangering mechanism of the endangered species. Therefore, the population research of endangered species has become one of the frontier fields in the area of today's ecology and conservation biology research. The achievements will be of great significance for future development of ecology theory and the protection of endangered species.Tanichthys albonubes, a kind of small cyprinidae fish, is one of the levelⅡprotection aquatic wild animals in China. It mainly inhabits in headwater streams and the conjoined drainages of rice fields and marshes in small hill regions of south China. Currently, the research data of Tanichthys albonubes population ecology is relatively insufficient. In the research of fish population ecology, the alteration of population quantity is the key point, and it is affected by mortality and migration. Noticeably, migration is an important way for populations to response to extinct pressure. This paper conducted pilot study of the natural mortality of Tanichthys albonubes by means of otoliths technology and discussed the feasibility of doing the migration research of natural Tanichthys albonubes metapopulations with Alizarin complexone. The main research achievements are as follows:1. Estimation of the early mortality of Tanichthys albonubes population with three methods. The investigations which were carried out for two streams in Yinlin area, Conghua, Guangzhou illustrated that Tanichthys albonubes population has lower early mortality, compared with other fish species,. The natural mortalities are 0.033 and 0.036 with day-age distribution method, while they are 0.024 and 0.025 with CPUE method. For one of the two streams, the mortality is 0.028 in fence in-suit test.2. Establishment of the static life table of Tanichthys albonubes population. The survival curve is in type 1 range, suggesting that larvae of Tanichthys albonubes showed higher survival rate, while older individuals showed higher mortality. The high survival rate of larvae matches to K-Selection characteristic, however, the characters of fast growth, early sexual maturity and small body type of adults match to r-Selection. This phenomenon proved that the life-history strategy of Tanichthys albonubes is not the typical r/K selection.3. Test of the parameter and effect of alizarin complexone as marking material. Experiment results showed that alizarin complexone can mark Tanichthys albonubes otoliths very well, and will not affect the Tanichthys albonubes's vitalmovement. Moreover, the marks could exist a long time and could be detected conveniently. Considering mortality and marking effects, the best concentration of alizarin complexone is 80mg/L for larvae and 150mg/L for adults, under 28-30℃water and 24-hour soaking period.