A Quick View on Biology of Near Threatened Peacock Eel (<i>Macrognathus aculeatus</i>) in Khulna Region of Bangladesh

Abstract

The Peacock eel, Macrognathus aculeatus is a near threatened highly valuable small indigenous species in Bangladesh. It is not only toothsome nutritive table fish but also notable aquarium species but still rely on natural stock. Keeping in mind the paucity of information on the biology which is crucial to develop artificial propagation and culture technique of this species, the present research was performed as an attempt to contribute to the information on the taxonomy and other biological aspects of M. aculeatus. Total 50 samples were collected from Khulna region during April to May 2014 to assay. The taxonomical study revealed that the total length, standard length, head length, eye diameter, pre and post orbital length; length of dorsal, anal and caudal fin; length of upper and lower jaw; body depth and width, distance between dorsal fin to caudal fin ranged from 17.00-21.00, 15.00-19.00, 0.80-3.00, 0.20-0.40, 0.50-2.10, 0.30-1.70, 3.10-6.70, 3.50-6.30, 0.50-1.50, 0.30-1.00, 0.70-1.80, 0.90-2.30, 0.60-1.20, 0.70-2.40 cm respectively, additionally meristic character’s formula appeared like D. 19 - 39, A. 11 - 18, C. 29 – 52, L. 11-15 and number of eye spots on dorsal fin, 3-10. Turning to the biological inquiry which showed that the fish weight (g), gonad weight (g), liver weight (g), gut weight (g), gonadosomatic, alimentosomatic and hepatosomatic index and condition factor ranged from 15.10-28.60, 2.32-3.18, 0.029-0.044, 0.64-1.08, 9.69-14.79, 2.58-4.15, 0.11-0.19 and 0.30-0.40 respectably. The mean values of hepatosomatic and alimentosomatic indices persuaded greater liver activity and feeding intensity in M. aculeatus. Moreover, stomach content depicted that the diet of peacock eel composed of small fish species, small prawn, prawn larvae, earthworm, water strider, insects pupae, Metaphire posthuma, Caenorhabditis, sand and mud for instance, which in brief expressed that M. aculeatus is omnivorous in its feeding habits. Indeed, this preliminary research outcome would be utile for the species identification, seed production, developing culture technologies as well as biodiversity conservation of this near threatened fish species.