Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/339
Title: OBSERVATIONS ON THE AGGRESSIVE BEHAVIOR OF HETEROBRANCHUS BIDORSALIS AND ORECHROMIS NILOTUS IN CO-CULTURE
Authors: OKONJI, V. A.
Issue Date: 2004
Publisher: NIGERIA JOURNAL OF APPLIED SCIENCE
Series/Report no.: 22;
Abstract: Observation was made on the aggressive behavior of the fingerlings of two fish species. Heterobranchus bidorsalos and Oreochomis niloticus commonly used in polyculture. Fairly even sized fish of 50 ± 0.4g H bidorsalis and 30 ± 0.3g O. niloticus were used. The study was carried out using indoor aquarium tanks measuring 30 cm x 45 cm x 60 cm. The observation was made in three treatments namely Hetreobranchus bidorsalis alone, O niloticus alone and combination of H. bidorsalis and O. niloticus. Each treatment was replicated thrice; and a total of nine (9) tanks were used in all. Observation was made and recorded by using a five point scale designated as 1 – unbruised (non-aggressive), 2 – slightly bruised (slightly aggressive) and 5 mortality (death). Observation on aggressive behavior was made and noted during feeding. Survival rate was taken. The fishes were fed 3% of their body weight divided into two daily rations; with a feed containing 30% crude protein. The experiment was designed as a complete randomized. Data were analyzed using table of analysis of variance. The results on observation showed that there was significant difference in the aggression ratings of the treatments (P < 0.05). The rating showed that the treatment containing Heterobranchus bidorsalis only had the highest aggression rating of 4 (i.e highly bruised or aggressive) and lower 6 survival rate (50%). This indicated that the intra-specific aggression was highest among H. bidorsali. This was followed by the combination of H. bidorsali and O. niloticus with a mean rating of 3 – (moderately aggressive). Bruises were observed mainly at the dorsal, ventral and caudal sides of H. bidorsalis. It was noted that though highly cannibalistic, the length of H. bidorsalis makes it easily prone to attack by other fishes of the same species, particularly when it is feeding and loses its guard. The uniform size of O. niloticus combined with H. bidorsalis, and the sharp guard and speed of O. niloticus makes for easy escape from the highly cannibalistic H. bidorsalis. It was recommended that stocking of H. bidorsalis and O. niloticus in polyculture will increase the survival rate and harvestable number of H. bidorsalis.
URI: http://hdl.handle.net/123456789/339
Appears in Collections:Abstracts

Files in This Item:
File Description SizeFormat 
NIGERIA JOURNAL OF APPLIED SCIENCE.pdf203.33 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.