Pakistan, Feb. 18 -- Dawn is still just a smudge of rouge on the horizon, but at the port of Mirissa on Sri Lanka's southern coast, an unusual daily challenge for locals is under way: how many tuna can you fit on a tuk tuk?

The rules seem simple: buy as much of that day's catch as you can from the extravagantly-decorated boats jostling for a berth in the harbour, pack it on to your three-wheeled scooter and drive away at speed.

Think Ben Hur in Billingsgate.

My family and I are here not to observe John West's delivery squad, but to climb aboard the 50 ft catamaran Jade, which waits for us at the far end of the quay, and head a few miles offshore for Mirissa's other great sport: whale watching.

We're in luck. Sort of. Though the mighty...