Study of the Length-Weight Relationship and Condition Factor of Five Fish Species from Nkoro River, Niger Delta, Nigeria

摘要

The length-weight relationship and condition factor of five fish species from Nkoro River in the Niger delta region of Nigeria was studied for twelve months using data obtained from fishers. The fishers used a wide range of fishing gear such as hook and line, long line, cast nets, gill nets and traps. Fish specimen randomly and identified using keys and descriptions. Specimens were stored in coolers containing ice and transported to the laboratory for further analysis. Total length and weight were measured using standard methods. The mean lengths and weights of the classes were used for data analysis, the format accepted by FISAT. The degree of association between the length and weight was computed from linear regression analysis. The respective exponential equation for the length weight relationship are: Ethmalosa fimbrata (W_t = 0.0162 (TL)3.199); Ilishia africana (W_t = 0.5998(TL)2.719) Sardinella maderensis (W_t = 0.0478(TL)3.580) and Cynoglossus senegalensis (W_t = 0.0326(TL)3.508). All species studied exhibited isom etric growth (b≈3) except S. maderensis and C. senegalensis with b≈3.6 and 3.5 respectively that exhibited positive allometric growth. The condition factor ranged from 0.917(I. africana) to 0.985 (C. senegalensis). There was difference in the condition factors for the combined fish species and the monthly factor for each fish species studied: E. fimbrata (0.85±0.015), I. africana (0.96±0.061), S. maderensis (0.87±0.072) and E. senegalensis (0.62±0.011), while C. senegalensis was 1.10±0.042. All species studied were in good condition (k ≤ 0.5).