Comparison of morphological and behavioral development patterns in Laotian three freshwater fishes as promising species for aquaculture in different taxa.
In Laos, aquaculture production has recently increased due to introduction of exotic species. Considering the regional fish fauna conservation, the necessity in indigenous fish species for aquaculture development in Indochinese region has been pointed out. Thus, the JIRCAS-LARReC project on development of indigenous species aquaculture has been implemented since 2006, and artificial seed productions of ten indigenous fishes (Anabantidae, Osphronemidae, Cyprinidae, Pangasiidae and Bagridae) have been succeeded. With these progresses, we have obtained some information on ecological/morphological features, being contributory to improving seed productivity as well as considerations on reproductive-survival strategies. Here, we have selected three species in different families, i.e., Anabas testudineus (Anabantidae), Trichogaster pectoralis (Osphronemidae) and Pangasianodon hypophthalmus (Pangasiidae) and present the hypothetical features of their reproductive/survival strategies based on behavioral information and morphological descriptions. Despite the similarity in egg sizes among these species, the sizes at onset of feeding of the former two were ca. 3.0 mm BL, while the latter >5 mm BL on day-2 after hatching for all. Subsequently, T. pectoralis showed the slowest growth with the longest yolksac period (ca. 10 days), A. testudineus intermediate (6 days) and P. hypophthalmus the fastest with rapid yolk absorption (2 days). Based on the reproductive behavior and yolksac periods, for T. pectoralis, slow growth is allowable due to foam nest (protection of eggs and newly-hatched larvae), parental care and long yolksac period. By contrast, fast growth is required due to quick yolk absorption without any parental cares for P. hypophthalmus, and A. testudineus was positioned in-between.