Effect of Host Condition on Intestinal Parasite Load and Prevalence in Malapterurus Electricus (Gmelin, 1789) (Siluriformes: Malapteruridae) in Lekki Lagoon, Lagos, Nigeria

Abstract

Host condition had effect on therate of infection and greater effect on intestinal parasite load in Malapterurus electricus . These vary among sex, sizes and weights of conspecific individuals. This was investigated  over a
period of two years.A total of  340 fishes from the lagoon were caught and dissected for intestinal helminth parasites and the condition factors of all individuals were determined. Median condition (K < 2.33 and K > 2.33)
was used in grouping the individuals. The rate of infection was higher among individuals of high condition status (29.41% to 31.76%). Male individuals of high condition had greater infection rate than their low condition males (33.65% to 29.25%), but their female individuals had a lower infection rate compared to the low condition females (28.88% to 29.41%). Percentage parasite load among conspecific males of high and low condition within the weight 10g to 60g had their parasite load as 28.76% and 15.93% respectively.  The females of low condition had a greater parasite load of 13.27% compared  with the high condition females, 7.08%. Within the low and high condition individuals of weight 10g to 60g and 60g to 130g, the males had higher load than their females. Low condition males of length, 9cm to 15cm and 15cm to 22cm had greater parasite load than their high condition males, 9 – 15cm
(14.61%, 10.62%) and 15 – 22cm (22.57%, 11.06%) respectively. This also applies to the females, 15 – 22cm (8.41%, 3.54%) except  the females within length of 9cm to 15cm (10.62, 11.06%). Pre-existing variations in the competitive ability of hosts has potentially important implication for parasite infections as well as their individual parasite load.
Monitoring health condition of fish population provides vital information for ecotoxicologist and toxicologist for improved environmental monitoring.

Keywords: Intestinal Parasite, Prevalence, Malapterurus, Electricus, Lekki Lagos.