It’s been a quiet summer in the waters of Alaska.
With zero cruise ships carrying whale-watchers and glacier gazers—a situation which temporarily boosts the state’s population of 730,000 by 1.4m individuals—the humpback whales in the vicinity have grown much more talkative.
This is the impression that delighted researchers are getting.
Every summer, East Australian humpback whales migrate from the feeding grounds in Antarctica to their breeding grounds in the Great Barrier Reef. They remain there for about several months, before making their way around the southern Australian coast back to Antarctica for the winter.
This scenario may one day become reality. And to be efficient, such robots would need to be maneuverable and stealthy, and be able to closely mimic the movements of the marine creatures.
Scientists like Keith W. Moored are working on the next generation of underwater robots by studying the movements of dolphins and whales. "We're studying how these animals are designed and what's beneficial about that design in terms of their swimming performance, or the fluid mechanics of how they swim."
In November 2016, a 7.8 magnitude earthquake in New Zealand triggered underwater mudslides in the underwater canyon off the coastline. This led to high-velocity currents to flush 850 tonnes of sediment from the canyon into the ocean.
This "canyon flushing" caused what was once a diverse ecosystem of invertebrates along the Kaikoura underwater canyon to become as "quiet as a desert."
A paper in the Deep Sea Research Part I journal describes how sperm whales were subsequently affected by the quake and how they changed their foraging habits as a result.
After studying 186 live strandings of healthy gray whales from 1985 to 2018, researchers at Duke University concluded that whales' navigational sense is affected by solar storms taking place as far away as our sun.
The researchers based their findings on the fact that the strandings are more likely to occur on days when there are more sunspots. Linked to solar storms, sunspots represent sudden releases of high-energy particles from the sun. These may disrupt magnetic orientation behaviour when they interact with the Earth’s magnetosphere.
The Wildlife Trusts, which comprises 46 individual wildlife trusts around the country, reports record numbers of more than 800 sightings of whales, dolphins and seals in the waters of the United Kingdom in 2019.
Its Yorkshire project reported hundreds of individual sightings by trained citizen scientists. Among these were a pod of bottlenose dolphins making their way from Scotland to Flamborough Head in East Yorkshire-the farthest south they had been officially identified.
Lunge-feeding humpback whales plunge into dense schools of small fish to feed on them. However, these small fish tend to be pretty fast. So, just how do huge whales sneak up on such speedy prey if they are as huge and overbearing as a ... well, whale?
This question became the focus of a study at Stanford University. Its findings was subsequently published in the Proceedings of the National Academy of Sciences journal.
After studying humpback whales off Queensland's Peregian Beach, researchers discovered that the whales’ ability to communicate and socialise is adversely affected by the noise and presence of boats.
In some cases, the mammals’ communication range is reduced by a factor of four.
"It appears that groups of humpback whales tend to socialise much less in the presence of vessels—in this study, mostly small fishing boats—compared to when there aren't any present," said Rebecca Dunlop from The University of Queensland's Cetacean Ecology and Acoustics Laboratory.
Japans announcement that it is withdrawing from the International Whaling Commission and will resume commercial whale hunting next year, have sparked swift condemnation from other governments and conservation groups. For many years Japan has hunted whales for what it calls "scientific research" and to sell the meat, a programme widely criticised by conservationists.
When air-breathing mammals dive, their lungs compress. The ultra-deep-diving feats of some marine mammals go beyond our current understanding of respiratory physiology and lung mechanics. But historically, researchers assumed the chest structure of marine mammals meant their lungs compressed automatically at great depths, an adaptation that prevented them from taking up excess nitrogen and getting the bends.
