In an earlier post, we mentioned the recent appearance of mothers with calves in Hervey Bay. Humpback whales do not all migrate at the same time; rather, multiple group types will be predominantly seen at different points throughout the migration.
The earliest pulse of whales to arrive in Hervey Bay is sub-adult whales; meaning whales that are sexually mature but have not yet reached their full size. Sub-adults in this area seem particularly curious about the vessels, and the early portion of the season is well known for “mugging” events where the whales approach the vessel. Later in the season, mothers and calves begin to migrate through the area, and the sub-adults continue their migration toward their Antarctic feeding grounds. Mothers with calves tend to stay in the tropical breeding areas longer than the sub-adults, likely to allow the calf more time to build up its muscles and blubber layer before beginning the migration southward. The protected waters on the westward side of Fraser Island provide a safe, sheltered stopover for these mothers to rest and nurse their calves.