Study On Otoliths Microstructure Of Tanichthys Albonubes And Research On Age Structure Of Wild Tanichthys Albonubes

The microstructure of larval Tanichthys albonubes's otoliths and age structure of wild Tanichthys albonubes were studied. Three main parts were included in the present dissertation:Part1:"Foreword", summarized the development of otoliths studies on microstructure and applications in world. Otoliths microstructure were mainly used in fish aging, early growth, estimating on spawning period, incubating period and spawn areas, evaluating on early life history events, identifying fish population, early mortality and class recruitment, habitation condition. The basic informations of Tanichthys albonubes were also introduced in this partPart2:"Study on otoliths microstructure of larval Tanichthys albonubes", the morphology, formation and deposition of the first increment and the rate of increment deposition were studied for sagittae, lapilli, and asterisci from larval Tanichthys albonubes. The samples from embryonic development of late stage to larval Tanichthys albonubes's were collected continuously. Three pairs of otoliths were removed from the fish. Morphology of sagittae were undergoing changes from round, oval, rhombic to pear-shape; morphology of lapillus were undergoing changes from round, oval to pear-shape. Sagittae and lapillus are apparently formed before hatching, and asterisci were observed 23 days after hatching. Most otoliths had one nucleus and one primordium; however, there were also a few with more than one nucleus and primordium. The first growth increment in otoliths was observed one day after hatching. Because of their readability and conservative growth, lapilli are considered the preferred otolith structure for age determination of Tanichthys albonubes.Part3: "Research on age structure of wild Tanichthys albonubes", groups of wild Tanichthys albonubes were collected from June 2005 to April 2006 every two months. The...