Our studies showed that the dolphins were surfacing less regularly in the presence of vessels and this response was further enhanced during vessel approaches.

A dolphin surfaced below them, calling out a musical welcome before again seeking the depths.

Three dolphins surfaced close by.

On cue, the dolphin surfaced and pushed her fin against the hand Theo idly circled as she trod water.

She hadn't gone a hundred metres when the dolphins surfaced around the boat, three of them; agitated, tuning in on her distress.

The dolphins doubled back, surfaced twice more, and disappeared.