• More than 150 endangered dolphins, known commonly as false killer whales due to their resemblance to killer whales, were found stranded in the Australian state of Tasmania’s northwest coast near Arthur River. 

• Australian authorities said these false killer whales will be euthanised after bad weather and the isolated location hampered efforts to push them back into the waters.

• In 2022, 230 pilot whales stranded further south on the west coast at Macquarie Harbor.

• The largest mass-stranding in Australian history occurred in the same harbour in 2020 when 470 long-finned pilot whales became stuck on sandbars. Most of the beached whales died on both occasions.

False killer whales

• False killer whales (Pseudorca crassidens) are large oceanic dolphins that resemble orcas (killer whales). 

• They are found in tropical and subtropical oceans worldwide, generally in deep offshore waters. 

• They are classified as near threatened by the International Union for Conservation of Nature (IUCN), with some populations at higher risk.

• As apex predators, they help maintain ecological balance by regulating prey populations.

• They are highly social animals that travel in groups, which may explain their tendency to strand together.

Causes of Mass Stranding

• Mass stranding of marine mammals, especially whales and dolphins, is a recurrent phenomenon, but the exact causes are not fully understood. 

Some key factors include:

1) Natural Causes

• Navigational Errors: Since they rely on echolocation (biosonar), disruptions due to underwater geomagnetic anomalies or shallow waters can confuse them.

• Following a Leader: These animals travel in tight-knit pods, so if the leader makes a wrong turn, the entire group may follow.

• Infections or Diseases: Certain viruses, like morbillivirus, can affect their nervous system and cause mass strandings.

2) Climate Change & Environmental Factors

• Rising ocean temperatures and changes in ocean currents can disrupt their migratory routes.

• Extreme weather events, such as storms, may force them into unfamiliar or dangerous coastal areas.

• Underwater noise pollution from ships, military sonar, or industrial activities can interfere with echolocation and disorient them.

3) Human-Induced Causes

• Fishing and Bycatch: Accidental entanglement in fishing nets can lead to injury and death, indirectly increasing strandings.

• Plastic and Chemical Pollution: Marine pollution, including ingestion of plastics and toxins, weakens their health.

• Habitat Destruction: Increased human activity near coastal regions may reduce their food availability.

(The author is a trainer for Civil Services aspirants.)