Molecular analysis of the breeding biology of the Asian arowana (Scleropages formosus)

Abstract

The dragonfish or Asian arowana (Scleropages formosus Müller & Schlegel, 1844) is one of the few living, `near-basal¿ teleosts belonging to the family Osteoglossidae. This CITES-protected species possesses a fascinating collection of biologically interesting characters that could be important for the study of basal vertebrate breeding biology, mating behavior and mate preference. We report here, to the best of our knowledge, the most detailed documentation of the breeding behavior, including mate choice and observed mating strategy, of S. formosus. For the analysis of mate choice, we created the ¿genetic mating map¿ for three ponds containing the total of more than 60 brooders over a 3 yr period, using 12 highly polymorphic microsatellites. Our data indicated that there were no multiple paternities, only single paternity in the 100 clutches of offspring sampled. The interspawning interval ranged from 2 months to 17 months. Parentage assignment, together with identification of the maternal and paternal genotypes using mitochondrial haplotyping, demonstrated that Asian arowana practiced both polygamy and monogamy. We also reported the unusual form of egg thievery practiced by the Asian arowana and a transient modification of the buccal cavity in the male brooders in preparation for the mouthbrooding event. Our data are important not only for better understanding the breeding biology of this unusually interesting bonytongue, but also for their potential to improve the existing aquaculture programs.