SYDNEY, April 9 (Xinhua) -- Every year between June and November, thousands of humpback whales head north from Antarctica's food-rich Southern Ocean, in search of warmer waters.
One of the most popular destinations for these vacationing whales is Australia's east coast, but this year the migration season has started much earlier.
"(This is) the first time they've been spotted in numbers this early," rescue manager Leigh Mansfield from the Organisation for the Rescue and Research of Cetaceans in Australia (ORRCA), told the Australian Broadcasting Corporation on Tuesday.
"There's always been the odd one travelling in March and April, but this is the most we've ever had," Mansfield said.
According to ORRCA's second vice-president Jools Farrell, it's likely the 15-20 whales that have already been sighted on Australia's east coast are younger males.
"They want to get up there to see if they can have a bit of a fun time with a female before the bull whales come up," she said.
"Once the bull whales are traveling, they're the adult males, the young yearlings don't have a chance," she said.
Expected to be one of the busiest whale-watching seasons in memory, Mansfield said, "once we get into June, the number escalates, and from about mid-June for about a month we average about 300 to 400 whales a day".
