Whale strandings - what causes them?

Keskiviikko 22.2.2023 klo 16.00 - Mikko Nikinmaa

The stranding of whales almost invariably result in the death of the animals before they can be returned to water. This is because when whales start to dry, their temperature increases since the surrounding water is not there to cool the body. The body temperature increases until it is lethal. To limit the temperature rise, stranded whales are flushed with water. During the recent past whale strandings have become more and more common. They are one of the symptoms of disturbances in oceanic environments, and may have various reasons. Regardless of the ultimate reason, it is possible that the whales make a decision to commit suicide because of the environmental stress. This can happen, as whales have very complex brains, and appear capable of conscious choices, as, e.g., commit suicide.

However, many of the strandings take place to injured whales. One of the biggest causes of whale injuries is a collision with ship. Because of the injury, the whale may not be able to swim properly and is washed ashore. Also, whales use sea currents to help them in swimming. As a result of climate change, the direction and strength of the currents may have changed so that when the whale thinks that it is swimming normally using the help of the current, it ends up stranded. By far the most important disturbance to whales is noise pollution. This is because long-distance acoustic communication is a major feature of whale life. If acoustic communication is disturbed enough, the whale may decide to commit suicide.

Sounds travel long distances in water. As a result, whales can communicate with their mates tens of kilometres away. This is the way they find partners for reproduction, inform of good food sources etc. Ships and motorboats make a lot of noise in the oceans. The noise levels may disturb whale communication. And the sea traffic has become more intensive and noisier in the recent past disturbing the whales more and more.

Kommentoi kirjoitusta. Avainsanat: noise pollution, climate change, ship traffic

Noise in the seas ? another anthropogenic problem which could be solved

Keskiviikko 10.2.2021 klo 14.08 - Mikko Nikinmaa

Sound moves faster and longer in water than in air. Different animals use all sorts of sounds in communication. Dolphins top the list with up to 70000 different sounds. It is probably even higher than human sounds – a person with 20000 words has a good vocabulary. Grey whales’ mating calls travel many kilometers in water in order to reach a suitable mate. Thus, the biogenic sounds are important for the functioning of animal populations in aquatic environment. Notably, when I was a child, and we were angling, one needed to be very quiet so that fish would not hear us, because they would do it a long way away.

With an increase of marine traffic and all sorts of other human endeavours in the seas and their shores, the soundscape of the oceans has changed immensely during the recent decades. Anthropogenic noises have even been suggested to be behind the shoring of whales.  In a recent number of Science (Duarte et al., Science 371, eaba4658 (2021)), Duarte et al. reviewed “The soundscape of the Anthropocene ocean” indicating the many problems for aquatic life. However, it would be possible to modify the anthropogenic sounds so that the soundscape of marine life would be acceptable. Thus, with this human-induced problem it is more or less the same as with climate change: we know what should be done, and we have the technical means to do it. However, we lack the political and economic will to do it.

GREED of the present generation decreases the possibilities for sustainable life of future generations.

Kommentoi kirjoitusta. Avainsanat: noise pollution, anthropogenic disturbances

Mass suicides of whales?

Keskiviikko 15.2.2017 klo 20.23 - Mikko Nikinmaa

There were several hundred whales stranded in New Zealand. Because whales are not dumb they could easily avoid being stranded. The only thing it would require is to start swimming to the opposite direction, when the water gets shallow. But the whales decide not to do it. Instead they continue to go to the beach, where they know that they cannot avoid heating up and soon dying. This makes it a purposeful act of suicide.

Why would whales decide to commit mass suicide? There is a simple reason for that - noise pollution. The propellers of the millions of boats and ships transfer the engine noise to water where it travels hundreds of kilometers. The noise under water is about the same amplitude as that well heard by whales, and is making their head burst. Rather than letting that to go on for days, months and years, they end it by stranding...

Kommentoi kirjoitusta. Avainsanat: noise pollution, marine contamination, hearing