RELATIONSHIP BETWEEN BASIC MORPHOMETRIC MEASUREMENTS, GROWTH PATTERN AND GROSS CARCASS VARIATION IN PROXIMATE COMPOSITION OF THE BODY PARTS OF ELECTRIC FISH (Malapterurus electricus) FROM AGAIE- LAPAI DAM, NIGER STATE, NIGERIA

Abstract

A total of one hundred and twenty (120) electric catfish (Malapterurus electricus) specimens, a commercially important freshwater fish inhabiting Agaie-Lapai dam, Niger state, Nigeria were collected to evaluate the relationship between basic morphometric measurements, growth pattern and gross carcass variation in proximate composition of its body parts. Fish samples were collected forth-nightly with artisanal fishing gears (gillnets, cast nets and seine nets) for a period of seven months. The results of the biometrics showed that the fish sample had a standard length of 12-19.93cm with mean value of 15.76 ±2.08, with total length ranging from 14.30 – 21.59 cm with a mean value of 17.97 ± 2.22 and the body weight ranging between 26.1- 106.50g. The growth pattern analysis depicted that the fish was positively allometric with b value of 3.14 and condition factor “K” ranged from 1.13 – 1.93 with a mean value of 1.48±0.22. The results of the whole body proximate composition and gross carcass composition of its body parts showed that there was an inverse relationship between the body lipid and moisture in the whole body composition and that moisture was highest in the fish body in October and lowest in July while lipid was highest in June and lowest in October. Gross carcass variation of various parts of the fish showed that moisture content ranged between 55.99 and 64.42% and was significantly higher in the skin than other regions examined. The crude protein value ranged between 19.74 and 23.08% and the skin also had the highest significant value. The lipid and ashranged from 4.63 and 9.17% and 1.34 and 4.66%, respectively. The fillet region had the highest significant lipid, while the head region had the highest significant value in ash content. It could be concluded that the M. electricus of Agaie-Lapai depicted a strong significant correlation between the length and weight and the growth exponent “b” indicated a positive allometric growth pattern with a (K) value index above 1. Proximate analysis showed that the lipid and moisture were inversely proportional in the body of the fish while other nutrients in the body of the fish did not fluctuate significantly over time and nutrients were not evenly distributed among the body parts.