Fourteen species of Vibrio were screened for chitin-induced chitinase activity in culture medium. V. carchariae, V. alginolyrticus 283 and V. camphellii showed high levels of activity. Screening on agar plates containing swollen chitin showed high levels of chitinase activity by the same three species, and also by V. fischeri and V. alginolyticus 284. An affinity purification procedure was developed for the chitinase from ii. carchariae. The purified chitinase was active as a monomer with M-r 63 000-66 000, and displayed activity toward polymeric chitin from acetylated chitosan or from crab shells. N-terminal sequence analysis and immunological cross-reactivity confirmed that the enzyme belongs to the group A/chiA family of bacterial chitinases,