Though an official version of the incident is yet to come, Coast Guard sources said it was the hull of the boat that was hit by the firing and the injuries might have been caused by the wooden chips that stuck the fisherman, hurting them.
They said the boat crew declined to respond to the warning shots fired from the patrolling vessel and the announcement made through a loudspeaker to slow down.
The boat was later brought ashore and the injured fishermen rushed to the Medical College Hospital here and their injuries were stated to be mild, police and hospital sources said.
The boat which had nine fishermen aboard, was returning to Kollam after fishing in the sea off Kanyakumari area. It had been brought ashore and the remaining crew detained by the Coast Guard.
The owner of the boat, Jasmin George, said in Kollam that that the firing came from the Coast Guard vessel.
He said the boat crew might have failed to recognise the signals sent out by the patrolling vessel as they had been tired after fishing for the last several days.