Humpback whale sightings off Western Australia fell 60% during this year's migration

According to ua.news, citing ABC News Australia, the number of humpback whales observed this year during the annual migration along the coast of Western Australia from the Southern Ocean to the state's northern waters fell by 60% ua.newsua.newsua.newsOpen source ↗. Researchers also recorded fewer calves, more whale strandings and more animals entangled in fishing gear. Geographe Marine Research team leader Capri Jolliffe described the season as unusual for humpback whales.

Females with calves were seen less often during the southern migration after giving birth near northern Kimberley, according to ABC. Olaf Meynecke, a marine research specialist and Griffith University researcher, said reports of low whale numbers were also coming in regarding other Southern Hemisphere populations.

Possible causes

Meynecke said early sea ice melt may have shortened the time whales spend in feeding areas. In his view, lower food availability due to changes in krill populations and phytoplankton blooms also affects their condition. Researchers observed females that appeared thin and had depleted fat reserves needed to nurse calves.

Observations from the water

Cameron Birch, an experienced whale watcher from Broome, said his tour groups had to travel 10–12 nautical miles from shore, almost twice as far as usual. Instead of interacting with 10–15 whales a day, they often saw only two or three ua.newsua.newsua.newsOpen source ↗.

Birch does not consider the current decline a cause for alarm, citing cyclical fluctuations over the past 25 years. Meynecke said recorded whale entanglements in Australia this year rose to 60, up 20%. He stressed that some cases may go unreported and that further research is important, as humpback whales may be an indicator of changes affecting other large whale species as well.