DOI: 10.5176/2382-5685_VETSCI16.9
Authors: Prof J.N. Maina, Assistant Lect G.D. Kavembe, Dr. M.B. Papah, R. Mashiteng, Adjunct Professor C.M. Wood, A., Bianchini, L.F. Bianchini, Prof. H.L. Bergman, Associate O.E. Johannsson, P. Laurent, C. Chevalier & Dr. R.O. Ojoo
Abstract:
Exceptional physiological, morphological and behavioural adaptations have enabled Alcolapia grahami to tolerate the extreme environmental conditions of Lake Magadi (Kenya). They include high temperature, large diurnal shifts in the partial of oxygen (PO2), high alkalinity and pH. Sex ratios (SRs) and condition factors (CFs) were determined on populations of fish from nine isolated locations. Except for the population of fish in the Cement Water-Holding Tanks, where the female-to-male sex ratio was 4:1, in all the other places, the number of male fish markedly surpassed the female ones. On average, the female fish had a lower CF of 1.5 compared to that of males of 1.6. Exhibiting poor state, the CFs of the different populations of A. grahami are some of the lowest that have been reported in fish living under natural conditions. The skewed sex ratios and the low CFs of A. grahami indicate the severe environmental pressure that the fish is facing and may herald catastrophic and irrevocable decline in the fish numbers and their ultimate extinction. Temperature, pH, alkalinity, and PO2 appear to be the foremost drivers of SRs and CFs of A. grahami. Conservation of a fish that offers a singular glimpse into the extent animals can adapt to an extreme environment is an imperative.
Keywords: sex ratio, Alcolpia grahami, Lake Magadi, condition factor, extreme environment
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