The otolith microstructure of Pacific tarpon Megalops cyprinoides was examined to determine whether there were influences on the deposition of otolith daily growth increments (DGIs) during metamorphosis from leptocephalus to juvenile. Leptocephali collected in a Taiwanese estuary in August 2003 were fully grown and completed metamorphosis in approximately 10 d during rearing in environmental conditions similar to those in the wild. The metamorphic process was divided into Stages II and III based on temporal changes in external morphology, otolith growth rate, and Sr/Ca ratio. The otolith increment width (OIW) was comparatively small for the leptocephalus (Stage I) before the experiment, increased rapidly at Stage II, and reached a maximum at the beginning of Stage III. In contrast, the otolith Sr/Ca ratio decreased sharply after Stage II. Metamorphosis was accompanied by a breakdown of Sr-rich sulfated glycosaminoglycans (GAGs) in the body, a change of body organization, body length shrinkage, and otolith rapid growth; growth increments in otoliths were deposited daily throughout. The metamorphic process of the Pacific tarpon leptocephalus is analogous to that of the anguillid eel, and the mechanism of otolith DGI deposition during metamorphosis may be similar.

The Asian giant softshell turtle, Pelochelys cantorii, is a Class I protected animal in China and a CITES Appendix II species. In this paper, the behavior of 15 cultivated 4-month-old Asian giant softshell turtles was recorded in 1 day by a surveillance camera. Focusing on the posture act environment (PAE) and based on ecological functions, a PAE behavior ethogram of juvenile P. cantorii was constructed and analyzed. The results showed that there were 10 postures of young turtles, including floating, hanging, swimming, and lying, and 48 postures of the head and neck, mouth, eyes and nose, etc. Forty-six kinds of behaviors, such as ingestion, elimination, exploration, locomotive, rest, amicable, group and conflict, were recorded under 8 environmental codes. These findings will be helpful for the study of the behavior and conservation of P. cantorii and can also provide a reference for the study of the behavior ethograms of other soft-shelled turtles.