ABSTRACT
This study presents the effects of gastrointestinal helminth parasites infection on the condition factor (K) of fishes caught from Warri river, over a period 12 months (June, 2010 to May, 2011). Of 800 fishes (belonging to 56 fresh and brackishwater species) examined during the study, 222 (27.5%) were infected with gastrointestinal helminth parasites belonging to three phyla, Platyhelminthes, Nematoda and Acantocephala. The K values of fishes infected with gastrointestinal helminth parasites ranged from 0.03 to 5.05 while that of non-infected fishes ranged between 0.22 and 8.75. The mean K values were not significantly different (P> 0.05). Nevertheless, there was a significant difference in the K value between the sexes for the helminth infected fishes. The males had significantly higher mean condition factor (2.11 + 1.27) than the females (1.78 + 1.16) (P < 0.05). However, for the non-infected fishes, the females recorded a marginal higher mean K value of 1.85 + 1.50, than the males with a mean K value of 1.83 + 1.32 (P>0.05). The mean standard length (SL) of fishes infected with gastrointestinal helminth parasites in the K value range of 1.1–2.0 was significantly higher than that of non-infected fishes (P < 0.05). The results also showed that as the condition factor increased, there was a significant decrease in the standard length of fish.
KEYWORDS: Condition factor, gastrointestinal, helminth parasites, fishes, Warri river.