Whale season off to slow start
October, Rarotonga’s resident whale expert Nan Hauser says the mighty marine mammals should now “start to pour in, in greater numbers”.
“This season is incredibly strange, and we don’t know exactly why,” said Hauser. “It’s started out slow this year – we’ve only really actually seen 20 whales.
“Last year we had the best season we’ve ever had here in 25 years. We had almost 500 sightings – it was unreal.”
While Hauser doesn’t know for sure what the cause is, she has a theory as to why it has taken the whales longer to show up this year – she thinks it could be related to climate change.
Humpback whales migrate to Cook Islands and South Pacific waters from Antarctica, where they typically load up on krill and herring before making the long trek northward to mate, rest and give birth to their calves.
“These humpbacks, they fast for six to eight months – they don’t eat anything,” Hauser explains.
“They gorge themselves in Antarctica – I mean gorge themselves, totally. They just eat and eat and eat and eat.
“Then they migrate up and across Oceania and back down again, with no food.”
Hauser says the animals can lose up to a third of their body weight during this time.
“So if they weigh 45 tons they can lose up to 15 tons,” she says. “They’re living off their fat – by the end of the season they’re much thinner. It’s a noticeable difference.
“But here’s the thing – my theory is that this year they needed to stay down in Antarctica longer to eat.
“Because of global climate change, the water temperatures are changing so drastically that their food – the krill and the herring that they feed on – may have had to move, so their food may have moved.
“It’s the whole huge food chain. So if one food moves, the next food moves and the next food moves.
And the whales are at the top of the food chain, so if they’ve been going to a place in Antarctica where they know the food is and where they’ve been going for centuries, and the food’s not there, or there’s less food, then they’re going to have to stay longer to get those fat deposits on them.”
That said, Hauser also put forward the observation that there could still be plenty of whales around in our waters, but due to Rarotonga’s recent poor weather no one has been able to see them.
“The weather has been so bad, with the wind and the rain, that nobody has been able to go out as much as they want,” said Hauser.
“We’ve had a total of 22 humpbacks, which is so low.
“But we also go out and drop hydrophones, and we can hear them,” she added. “We can hear them every day, we can hear singers – the males sing. We can hear them but they’re way off shore.”
The sightings Hauser has actually recorded so far this season include two mother and calf pairings, a group of six from the very beginning of the season, a trio of “mother, calf and escort – like a suitor”, and several single whale sightings.
And in fact, just while CINews was talking to her on the phone, Hauser’s research assistant called in the sighting of a third mother and calf pairing, seen in the water off Kiikii.
“That’s hopeful,” said Hauser, now preparing to wrap up our interview so she can head out and follow up on the sighting. “I think we’re going to have a great season, I think it’s just late.
“But we are known to have good and bad seasons also.
This is the 21st year I’ve been here and the seasons really vary – sometimes you have a great whale season and sometimes you have a not so great whale season.
“We don’t know why – nobody does.”