STUDY OF ENDOHELMINTH PARASITES AND THEIR INFESTATIONS ON HOST, CLARIAS BATRACHUS (LINNEAUS)

Abstract

The study summarizes the percentage of prevalence, mean intensity, abundance and index of infestation of endohelminth parasites in walking catfish Clarias batrachus with the influence of temperature, humidity and rainfall during different seasons and months from March 2013 to December 2013. The present study also indicates the seasonal infection of different parasite in different sexes and size groups. Total 100 host fish were collected from different water bodies of Sylhet, Bangladesh for examination. Among them 75 species of C. batrachus were found to be infested with 1404 parasite by seven different endohelminth parasitic species of three different groups such as trematode, cestode and nematode. These species of parasites were i) Orientocreadium batrachoides, ii) Bovienia serialis, iii) Lytocestus indicus, iv) Lytocestus birmanicus, v) Djombangia penetrans, vi) Pseudocaryophyllaeus indica and vii) Paracamallanus spiculogobernaculus. Variations in prevalence were evident in different months and seasons. The high prevalence 100% occurrence in the month of November to December; while low prevalence 69% occurred in June. Seasonal investigation showed higher prevalence 85% in post-monsoon and very lower 67% in monsoon. The influence of environmental factors occurring parasitic infestation also observed. The temperature ranged 25-27 C was suitable for parasitic infestation during pre-monsoon and postmonsoon

season whereas heavy rainfall (609.7mm) and high humidity (77.67%) at monsoon decreased the infestation. Mean head length and weight varied with size and different level of infestation. In smaller and larger sized fishes, the percent gained of mean head length higher 8.0 at high level of infestation. The highest percent loss of weight 11.0 was observed in smaller length grouped (<13cm) fishes during high level of infestation whereas lower 3.0 in medium length grouped (14-18cm) fishes. The highest condition factors (0.86 and 0.73) were found in non-infested fish in small and medium length groups than infested ones (0.83 and 0.72). 0