Mass occurrence of bathypelagic chaetognath Eukrohnia fowleri from the Arabian Sea and Bay of Bengal

More than 250 individuals of a cosmopolitan bathypelagic chaetognath Eukroh nia fowleri were collected by ORI net from the Arabian Sea and Bay of Benga l. This high density is supported by high primary production and zooplankto n biomass in both areas. Body length ranged from 13 mm to 27 mm (av 21 mm) in the Arabian Sea and from 11 mm to 30 mm (av 18 mm) in the Bay of Bengal. Adults contributed 24% and 12% of total catch respectively from Arabian Se a and Bay of Bengal. Minimum body length of adult was 18 mm. The species in habit in the oxygen minimum layer in the Arabian Sea and Bay of Bengal. The tropical northern Indian Ocean supports relatively higher population densi ty of Eukrohnia fowleri as compared to other oceans.