Impact of Ectoparasites on Length-Weight Ratio and Condition Factor of Cultured Fish Species in the West Region of Cameroon

Aims: This study aims to analyse the effect of ectoparasite infections on length-weight relationships and condition factor of cultured fishes in the West region of Cameroon.

Study Design: A stratified cross-sectional study was used to select fish farms and individual fish per farm.

Place and Duration of Study: Fish farms in the West region of Cameroon between December 2018 and December 2019.

Methodology: Sampled fishes were identified and examined from ectoparasites and pathologies according to standard procedures. Their lengths and weights were measured to determine their length-weight relationships and condition factors. A total of 2254 fishes (692 Clarias gariepinus, 969 Oreochromis nilotichus, 593 Cyprinus carpio) were sampled.

Results: Overall, 34.87% of the sampled fishes were infected with ectoparasites (O. niloticus (34.37%), C. carpio (37.10%) and C. gariepinus (33.67%)). The prevalence rates were significantly influenced by size (P=0.001, X2=10.59) and weight (P<0.0001, X2=32.24) and negative allometric growth patterns (b < 2) were observed irrespective of the parasitic status of the fishes. Though the mean condition factor ranged from 1.07 to 3.01 throughout in the study according to species, sex and season and ectoparasite status of the fish, significantly higher (P<0.05) condition factors were observed for male fishes, fishes harvested during the dry season and uninfected fishes compared to female fishes, fishes harvested during the rainy season and infected fishes. Among the infected fished, the highest (p<0.05) condition was recorded in O. niloticus followed by C. carpio and C. gariepinus.

Conclusion: The study revealed that ectoparasite infection significantly influence length-weight relationships and condition factor of cultured fishes in the west region of Cameroon. Irrespective of parasitic status, there was relationship between body weight and length of fish. The control of ectoparasite infection of cultured fishes is vital for improved conditions, health and production yields in fishery sectors in Cameroon.