Morphometric comparison among three wild Nigerian strains of Heterobranchus longifilis (Valenciennes, 1840) and their fingerling intraspecific hybrids.

Abstract

Morphometric characterization was carried out in intraspecific hybrids of three wild strains of Heterobranchus longifilis obtained from three geographical locations inNigeria – rainforest,Onitsha strain, guinea savanna, Kainji strain and montanne vegetation, Jos strain with the aim of identifying the strains and their hybrids.  The adipose: dorsal fin relationship show that almost equidistant relationship (0.90) in the Kainji strain whereas there were longer dorsal fin inOnitsha (0.84) and Jos strains (0.77). Moreover, easily observable gaps between posterior dorsal and anterior adipose were identification marks forOnitsha and Jos strains and absent in the Kainji strain. The Onitsha-Jos hybrid complex had the widest gap (0.33 cm – 0.35 cm). A range of 50.00 – 66.70% retained this gap. The hybrid group with the least gap was the Jos-Kainji crosses (0.17 cm – 0.24 cm). Seventy-five percent of the offspring of the hybrid cross between female Jos strain and male Kainji retained this gap, whereas 100% of the cross-Kainji female x Jos male had this gap. Anal ray counts tend to decrease with increasing longitude but does not follow any pattern with increasing latitude. In addition, anal ray count was lowest in the strain collected from the montanne vegetation (1200m above mean sea level).