Karyotype of Papua’s Rainbowfish (Melanotaenia maccullochi)

Abstract

Melanotaenia maccullochi is freshwater fish distributed from the mid of south of Papua/New Guinea to Australia. Attractive color and shape of this species has the economical value as ornamental fish that caused the exploitation of the species so intensified. Some problems in rearing of this fish are low survival rate, growth rate, and male percentage. The other problem is a genetic information (such as chromosome) of this fish is so poor. The aim of the research is to explain the chromosome diversity of the fish. The information is needed for genetic conservation and aquaculture development. Cytogenetic study of M.maccullochi was focused on karyotype and to find out the information of chromosome. The research was conducted at Laboratory of Fish Breeding and Genetics, Faculty of Fisheries and Marine Science-IPB on June 2000 - May 2001. Chromosome plates were prepared by solid tissue technique (using 150 larvae) and analyzed after staining with Giemza solution. Diploid chromosomes number of M. maccullochi is (2N=48). Karyotyping of this fish shown that 48 chromosomes consist of 4 pairs subtelosentrik (ST) (no.1, 2, 3, and 21) and 20 pairs telosentric (T). The sex chromosomes have not yet identified.