Organo-somatic Index and Condition Factor of Clarias gariepinus (Burchell, 1822) Sub-adult Exposed to Sub-lethal Concentrations of Gold Crew Oil Spill Dispersant

Abstract

Organosomatic index and condition factor of fish is one way to assess the general health of fish and monitor the influence of environmental factors on fish. The organosomatic index and condition factor of Clarias gariepinus exposed to sub-lethal concentration (0.0ml/L (control), 0.075ml/l, 0.15ml/L, 0.3ml/L and 0.6ml/L) of gold crew oil spill dispersant was conducted over a two-week period. Ten fish (three replicates) were kept in a static renewal state for two weeks in a row and the liver, spleen, heart, gonad and viscera were excised on a weekly basis and weighed using a digital weighing scale, before the excision of the organs the fishes were first weighed and the length taken in cm. Physical and chemical parameters of the test medium was also conducted in-situ using a multi-parameter checker (Extech DO 700).Results for physicochemical variables revealed values for; temperature;  week 1; 28.30°C (0.15ml/L ) - 27.20°C(0.0ml/L), week    2; 26.00°C (0.0ml/L,0.075ml/ and 0.3ml/L) -25.67°C (0.15ml/L and 0.6ml/L) , pH; week 1 ; 4.82(0.15ml/L) -4.06 (0.0ml/L), week 2: 7.38 (0.0ml/L) -5.94 (0.6ml/L), DO; week 1: 6.12mg/l(0.0ml/L) -5.00mg/l (0.15ml/L, 0.3ml/L and 0.6ml/L), week 2: 6.01mg/l (0.0ml/L) – 4.93mg/l (0.3ml/L), TDS: week 1 89.00mg/l(0.6ml/L)-154.00mg/l(0.3ml/L), EC: week 1: 188.33 µs/cm (0.6ml/L) - 166.33 µs/cm (0.0ml/L), week 2: 357.67 µs/cm (0.0ml/L) - 238.67 µs/cm (0.075ml/L). Results for organosomatic index revealed values for; HSI; week 1; 0.41 (0.0ml/L) - 2.52 (0.15ml/L), week 2;  0.93(0.075ml/l)  –  1.52 (0.6ml/L); GSI; week 1; 1.58 (0.6ml/L) – 3.83 (0.15ml/L), week 2; 1.11 (0.0ml/L) – 4.66 (0.6ml/L), VSI; week 1; 2.91(0.6ml/L) – 3.70(0.15ml/L), week 2; 1.50 (0.0ml/L) – 4.33(0.6ml/L), SSI; week 1; 0.11(0.0ml/L) – 0.24 (0.15ml/L), week 2; 0.06(0.15ml/L) – 0.15(0.3ml/L), CSI; 0.07(0.3ml/L) – 0.16(0.075ml/L and 0.15ml/L), week 2; 0.11(0.0ml/L) – 0.19(0.6ml/L). Condition factor values revealed results for; week 1; 0.57(0.15ml/L) – 1.00(0.0ml/L), week 2; 0.71 (0.3ml/L) – 1.05 (0.075ml/L) depicting poor physiological condition for fishes in the treatment group. There is therefore urgent need for public awareness campaigns to educate communities about the risks associated with the dispersant use and the importance of minimizing their environmental footprint.