Prevalence, Intensity and Relative density of...

Prevalence, Intensity and Relative density of nematode parasites in marine fishes of Visakhapatnam, A.P, India

Author Name : P. Rosina George

ABSTRACT

The present study was conducted to find out the prevalence, intensity and relative density of nematode parasites in different species of marine fishes for a period of three year from January 2007 to December 2009. Out of 112 species of marine fish examined, 28 species were found to be infected by nematode parasites. Among the total number of 2500 fish specimens examined for parasites, 198 fish (8% of total sample) were infected and are confined mostly to intestine. The highest prevalence of infection was observed in May (2007-2009) when the average sea water temperature was 30.06⁰c respectively. There was correlation between seawater temperature and prevalence of nematode infection but salinity in the marine environment showed negative impact on the intensity of nematode infection. Nematode infection increases with increase in temperature. From the total period of 3 years the nematode parasites exhibit a marked seasonal occurrence. The peak infection was recorded in fish Upeneus vittatus (62.5%), Upeneus sulphureus (50%), Thryssocles mystax (50%) and Saurida undosquamis (46.6%) with the parasites Contracaecum vittati and Contracaecum sp in the summer season i.e from March to June. The male parasites are very rarely found whereas the females were recovered from different organs of host.

KeyWords:Nematode parasites, prevalence, intensity, seasonal distribution, temperature.