That's generally when they feed..... I remember at the end of one long dive in the Hol Chan Marine Reserve but outside the reef, not in the channel referred to above, seeing in the space of 20 minutes or so a hammerhead and a tiger shark just cruising around, watching us. We had decompression to serve out and couldn't exit the water, and although it was very interesting watching these two big sharks the experience was slightly more exciting than I normally like.
But JDT - we survived, as you will when I eventually persuade you to try it!