Concerns over whale watching are being discussed by the International Whaling Commission this week. So is it harmful to whales?
At least 13 million people go whale watching every year and it is an industry estimated to be worth £1.32bn ($2.1bn), according to the International Fund for Animal Welfare (IFAW). In short, it is very big business.
Organised whale watching - typically going out in boats to see them swim - started in the US in the 1950s and is now done in 120 countries worldwide. The industry is still growing, with countries in Asia and Latin America getting more involved.
But the size of the industry has increased concern about its impact on whales. A series of measures to control badly managed whale watching is being discussed by the International Whaling Commission (IWC) at a meeting in Jersey. So does it harm the mammals?
Whale watching can have an impact on their natural behaviour, including their ability to feed, rest and rear their young. This can cause problems in the short and long term, say those working in the field of marine biology. Boats can also collide with the whales, putting everyone at risk.
"In the short term a boat interacting with whales can disrupt their activities, like stopping them foraging for food or resting," says Dr David Lusseau, from the Institute of Biological and Environmental Science at the University of Aberdeen.
"This can be no big deal once or twice, but problems start if this is repeated again and again over time. Whale watching is a big industry - in some places boats can go out 10 times a day.
"In the long term this can have an impact of the whales' vital rates. Females can even stop producing enough milk for their calves, which can decrease the survival rate of their young. Ultimately the viability of a pod can be threatened."
The Whale and Dolphin Conservation Society (WDCS) says harm can be done because whale watching is an industry established, like any other, to make money.
Some countries have specific legislation about whale watching, stipulating how many boats can be out at one time and what speed they can travel at. But even if they do, it's often hard to monitor the boats as they can go miles out to sea. Some countries don't even have voluntary guidelines and it can be a free-for-all.
"There is no such thing as a typical trip, they vary enormously depending on location," says Vanessa Williams-Grey, who heads the Responsible Whale Watch Programme at the WDCS.
"Badly run trips can translate into all sorts of negative reactions from the whales. They can stop resting or increase their respiratory rate. If they are using more energy this will have an impact on their health."
Travel company Oceans Worldwide offers whale-watching tours in Scotland. While whales are protect under wildlife laws in the UK, there is no specific legislation about whale watching. The company says it follows WDCS guidelines to ensure the highest standards on trips.
"It makes absolute sense to because if you cause stress to the whales they will only end up moving out of the area," says a spokeswoman.
Whales, however, can also benefit from the industry, say those in the field.
"It has huge benefits for people and the animals themselves as it turns people on to the magic of whales and dolphins," says Ms Williams-Grey. "This hopefully translates into a greater understanding of their conservation needs and a determination to help protect them against the myriad threats they face in the marine environment.
"This is not just vessels, but noise pollution, chemical pollution and of course deliberate hunts such as the current whaling activities in Iceland, Norway and Japan - and to a lesser extent elsewhere."
A lucrative whale-watching industry can function as an argument for not hunting them in pro-whaling countries.
The industry can also benefit local communities, some of whom have seen their fishing industries collapse. It is a case of getting the balance right, says Dr Lusseau.
"The economic benefits for local communities can be really positive, but you need a balance. If there is over exploitation and the whales are harmed in the long term then the industry will eventually collapse just like fishing."
No one is calling for an all-out ban on whale watching, people just need to chose trips carefully, adds Dr Lusseau. Advice is widely available.
The WDCS, which produces its own guidelines, says people should ask tour operators whether any regulations or voluntary codes apply in their area. Also, it is usually a good sign if a trip includes an onboard naturalist to provide educational commentary about the whales and the marine environment.
It's also worth remembering whale watching can be done from dry land. This is safest option and what the WDCS recommends whenever possible.