JUNEAU, Alaska -- A University of Alaska professor and graduate student are planning to study the impact whale watching has on humpback whales.

This summer, professor Heidi Pearson and one of her students will see how many whale-watching boats are in an area at once, and how close those boats are getting to the whales, the Juneau Empire reported.

"It's really a mixed bag in terms of what people have found," Pearson said. "Some studies have found no effect, some studies have found short-term effects such as interfering with foraging or resting or travelling. Some studies have indicated there could be some long-term effects in terms of perhaps stress, perhaps animals abandoning an area due to high whale-watch pressure. Those long term effects are really hard to nail down."

Some people in the Alaska whale-watching industry have said an increasing number of tourist vessels have become a problem. Others have said the vessels' practices are becoming more whale-friendly.

"We're looking at short-term responses to whale watch vessels," Pearson said. "But the other side of the study is benefits. Are there educational benefits that people receive by going on whale watch vessels? I think both of those are really important to look at."

Humpback whale populations in Juneau have increased to historic numbers in recent years, which has drawn more tourist vessels.

The North Pacific stock of humpbacks, which populates Juneau, has grown at a rate of 7 per cent per year. Ninety-five per cent of Juneau's humpbacks are from a population segment that has been taken off the endangered species list.

A 2015 report listed whale watching in Juneau as an estimated $35 million industry.

About 60 whale-watching boats will work out of the city this year. More than 1 million people are expected to visit Juneau as tourists this year, and a quarter of those tourists are expected to go whale watching.