OBSERVATION ON SKELETAL DEFORMITY IN HATCHERY-REARED RED SPOTTED GROUPER, Epinephelus akaara (Temmick et Schlegel) FROM LARVAL TO JUVENILE STAGE
Abstract: Skeletal deformity
is a significant problem in fish culture. The skeletal deformities in red
spotted grouper from yolk-sac to juvenile stages were examined through clearing
and staining of the cartilage and bone using Alcian Blue and Alizarin Red S.
The overall results showed that the pattern of incidence of deformities showed
an increase from preflexion to juvenile stages. The rate of deformities based
on ten elements of bone from preflexion to juvenile stages were as follows:
vertebral (42.6%—9.0%), dorsal proximal radials (4.8%—25.2%), neural spine
(0%—8.4%), haemal spine (0%—6.8%), hypural (1.3%—5.4%), anal proximal radials
(0%—5.4%), epural (1.3%—4.9%), arypural (2.0%—4.5%), lower jaw (1.3%—2.5%), and
upper jaw (0%). Vertebral and dorsal proximal radials were recognized as the
most susceptible parts to deformation. The main types of bone deformity were
lordosis, scoliosis, fusion, shortening, branching, supernumerary elements, and
saddleback syndrome. Development of saddleback syndrome was detected initially
in preflexion stage, which was accompanied by deformity of the neural spines,
dorsal proximal radials, and disposition of the distal radials and dorsal
spines in later life stages. The skeletal deformity encountered during the
larval rearing period could be caused by water surface tension.
Keywords: skeletal deformity;
red spotted grouper; Epinephelus akaara
Author: Eri Setiadi, Seiichi
Tsumura
Journal Code: jpperikanangg070010
