Officials at the Humpback Whale Marine Sanctuary said that the humpback whales are slow to return to Hawaii this year.  December marks the month of the humpback whale season, and they are an iconic part of Hawaii’s islands warm waters in winter.

These gigantic creatures help in generating income from tourists who visit the islands during the whale season. Ed Lyman, a Maui-based resource-protection manager and response coordinator for the sanctuary said that this was not a concern, but it’s of interest. One theory was that something like this happened as whales increased, he added. However, the hard numbers will be known to officials only after the annual whale counts, which take place in the last Saturdays of January, February and March.

“They don’t necessarily show up in the same place at the same time every year,” said former sanctuary co-manager Jeff Walters.

Usually, more than 10,000 whales swim from Alaska to the warm waters of Hawaii, to mate and produce offspring. Experts believe that El Nino disruptions and other factors may be responsible for the slow return of these marine creatures during the winter journey. Lyman said that this could mean that whales are spending more time feeding in northern waters. Officials at the sanctuary have reported that whales have been difficult to spot so far.

According to Associated Press, whales who travel annually from Alaska to Hawaii spend much of November though May around warmer environs, to populate.  There is also a possibility of more animals competing with each other for food resource, and it takes an energy reserve to make that long migration for over 2,000 miles, added Lyman. “What I’m seeing out there right now I would’ve expected a month ago,” said Lyman. The exact reason for the delay in the traditional migration is not yet known.