Vertebral column study on glass and Elver Eel of anguilla bicolor (McClelland, 1844)

Anguilla bicolor (McClelland, 1844) is one of the native Indonesian fish. Anguillids species exhibit catadromous life mode, that they are born in marine waters, then migrate as larvae to fresh or brackish water where they grow and mature before they return to the marine environment. The fresh water to marine migration was designed to reach their spawning side. Anguilla bicolor is a fish that exhibit extreme migration and can travel up to 2000 km. During migration Eel abstain from food and loose substantial amount of bone, where bones were reused as energy during migration. The cellular bone serves as a source of mineral release following osteoclastic resorption. The eel�s skeleton is structurally optimized to meet the metabolic challenge of fasting and simultaneous sexual development during migration. This study aimed to investigate the structure and ossification of vertebrae of Anguilla bicolor on glass eel and early elver eel phase. The study was following standard Inouye bone staining method. Result showed the number of vertebrae segments in the glass eel and early elver eel stage were 104 segments, all vertebrae segment already well calcified. However, both eel stage exhibit differences on bone length ratio, and the cranial bone ossification processes. The glass eel cranial bone mainly consists of cartilage bone, while in the early elver eel phase the cranial bone already ossified become compact bone. © 2020 Elsevier B.V., All rights reserved.