Development patterns and defining length at juvenile of two co-occurring Terapontids, Terapon jarbua and Pelates quadrilineatus, from Trang province coastal area, Southern Thailand

Abstract

This study aimed to describe development patterns and define length at juvenile of two co-occurring terapontid fishes. Terapon jarbua (n=366, 1.49-48.24 mm) and Pelates quadrilineatus (n=314, 1.64-54.13 mm) were collected from coastal area, Trang Province, Thailand. Specimens were divided into five developmental stages: preflexion larvae, flexion larvae, postflexion larvae, transforming larvae, and juvenile by study of morphometric character, meristic character and pigmentation pattern. The length at juvenile was defined by using a multivariate analysis of morphometric characters. The length at juvenile stage of T. jarbua and P. quadrilineatus began at 23.16 mm and 18.24 mm in standard length, respectively. All morphometric characters were significantly different (P<0.05) between transforming larvae and juvenile stage in both species. An understanding in development patterns can aid in the explanation of their ontogenetic niche shifts. Due to the actual timing of switches in diet and habitat, it usually relates to changes in morphology of fish. The increase of mouth and jaw were significant in the ontogenetic dietary shift. The increase of body depth, fin length and eye size were also important to the mobile ability and feeding habitat shift in terapontid fishes.

Keywords

• coexist adaptation
• larvae
• juvenile
• morphology
• terapontids