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Implantation of a New Micro Acoustic Tag in Juvenile Pacific Lamprey and American Eel
Published on: March 16, 2019
Morphological, ecological and physiological characteristics of downstream-migrating and non-migrating Pacific bicolor
Seishi Hagihara1, Jun Aoyama2, Daniel Limbong3
1Atmosphere and Ocean Research Institute, The University of Tokyo, Chiba, Japan.
Abstract:
This is the first study describing the morphological, ecological and physiological characteristics of two downstream-migrating and two non-migrating female Pacific bicolor eels, Anguilla bicolor pacifica. The total length and age of the downstream-migrating eels were 1005 mm and 10 years and 1110 mm and 11 years old, respectively, and those of the non-migrating eels were 892 mm and 8 years and 805 mm and 9 years, respectively. Silvering-related characteristics (silvering index, eye index, pectoral-fin index, gut-somatic index and swimbladder-somatic index) and reproductive physiological characteristics (gonado-somatic index, follicle diameter, oocyte stage, transcription of gonadotropins and concentration of sex steroids) of the migrating eels were more advanced than those of the non-migrating eels.
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