Occurrence of fish louse (Argulus sp.) on Indian snow trout (Schizothorax richardsonii) and golden mahseer (Tor putitora) in subtropical Himalayan Lake of Bhimtal, Uttarakhand, India

Abstract

Indian snow trout (Schizothorax richardsonii) and golden mahseer (Tor putitora) from cage culture unit of Bhimtal Lake were examined for fish louse (Argulus) infestation from August 2008 to January 2009. The percentages of S. richardsonii infected were 51.21, whereas abundance and mean intensity of infestations were 1.05 and 2.06 respectively. Maximum prevalence (70.1%) was observed in September with least in December. Percentages of host infected in T. putitora were 25 with abundance and mean intensity of 0.34 and 1.36 respectively. One to two percentage of fish stock was fungal infected. Measurement of crustacean parasite illustrated carapace length (CL) comprised 75% of average total body length (5.4 mm). Prevalence was positively correlated (S. richardsonii: r = 0.88; and T. putitora: r = 0.91) with decrease in water temperature. The results of mean intensity of Argulus infestation indicated an initial stage of infection in both the species. So the present study draws immediate attentions of fish health management towards enhancement of fish production in coldwater aquatic resources of India