It is also a new way for communities who once hunted the world's largest animals to earn a living, say the environmentalists who helped to set up the biggest whale
sanctuary in the Mediterranean.
"When I saw my first whale some 10 years ago, it changed my life completely," said Paolo Guglielmi, head of the marine unit at the World Wildlife Fund (WWF) Mediterranean Programme.
As if to prove his point, dozens of people on board the tourist boat rushed to get a glimpse of the grey back of a whale arching for a few seconds above the waves before disappearing again, leaving the crowd momentarily speechless.
"It's crucial to protect whales because they, as top predators, are at the top of the food chain in the oceans," said marine biologist Guglielmi. "By protecting whales and dolphins we can protect the whole environment they are living in."
Commercial whaling, together with irresponsible fishing, presents the biggest threat to sea mammals, killing thousands with unacceptable cruelty, conservationists say.
Three major whaling nations - Norway, Japan and Iceland - say the stocks of some whales, especially the small minke whale, have recovered and are plentiful enough for catching.
They harpoon whales despite a ban on commercial whaling imposed by the International Whaling Committee (IWC) nearly 20 years ago.
Norway says the whales damage fish stocks, while Japan and Iceland say they hunt them for scientific purposes.
"A live whale is worth much more than a dead whale. We are starting a whale-watching tradition"
head of the marine unit,
WWF Mediterranean Programme
Environmentalists say about 20,000 whales have been harpooned since the moratorium came into effect in 1986 and more than 1000 would be hunted down this year.
They are also concerned that the three major whaling nations appear to be gaining support in the IWC, the only global body devoted to whales, and that this month's IWC meeting could move towards lifting the ban on whale hunting.
Ecologists believe whale-watching, popular in the United States, Australia and New Zealand, not only educates people but can be an alternative way to earn money, providing jobs in villages which traditionally worked in fishing and whaling.
"A live whale is worth much more than a dead whale," said Guglielmi. "We are starting a whale-watching tradition."
One tourist boat which carries about 200 people can earn up to $303,800 in the summer season taking curious holiday-makers to track the whales.
But while whale-watching boats have increased five-fold, the populations of some species of whale have fallen by 80%. The time for change is running out.