Changing Planet

Marine life on the line

An entangled blue whale in Sri Lanka, January 2013. Photo credit Tony Wu.
An entangled blue whale in Sri Lanka, January 2013. Photo credit Tony Wu.

It reads like a mystery novel; the search continues for a blue whale entangled in a buoy line, heading towards Mexico from southern California. First spotted on September 4th off the coast of San Pedro, rescue teams tried to free the 80-foot whale but rough seas and failing light meant the operation had to be abandoned until the next day. To increase visibility, the rescuers tied a second buoy on the buoy line. Two days later, the rescue effort turned into a search mission as the leviathan vanished into the vast blue ocean.

The concerns related to entanglement are many fold – the animal could die of infection if the line cuts into its skin, or of starvation if the whale cannot eat because the line runs through its mouth. It might also become fatigued after dragging 200 ft of line and buoys behind it for many days. While US groups have rescued whales from entanglements before, they generally involve the smaller gray and humpback whales. A blue whale rescue of this nature is yet to be attempted.

Three days later, the whale was spotted 18 miles southwest of the Coronado Islands about 100 miles south of where it was first seen. Unfortunately, these waters are out of US jurisdiction and the local rescue group based in Mexico was too far south to get there before it disappeared again.

While entangled blue whales are a rare sight off the California coast, three incidences of gill net entanglement have been reported from the Gulf of St. Lawrence between 1979 and 2002. Back in January 2013 on the other side of the world in Sri Lanka, underwater photographer Tony Wu documented a whale that had a net wrapped through its mouth, along the sides of its body and wound around its tail. This individual was noticeably thin, and unable to dive. The scarring patterns around its tail stalk indicated that it had been attached to this gear for an extended period. While attempts to approach the animal for rescue were futile (and dangerous for untrained personnel), it is more than likely that this fishing net resulted in the tragic death of the whale.

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The blue whale was thin and wrapped in a net that went through its mouth, along the sides of its body and wound tightly around its tail. Photo credit Tony Wu.

Researchers cite the drift gillnet fishery for swordfish and sharks off California and Baja California, Mexico as a potential threat to blue whales off this coastline. Incidental catch of marine megafauna is a stealthy but significant threat. Much of the mortality resulting from fishing net entanglements are not recorded in fisheries statistics because animals caught in fishing gear swim away injured, or die with or without gear attached. This leaves us with no clear understanding of the overall impact of entanglement on these populations.

According to the IUCN RedList there are only about 10,000-25,000 blue whales left in our oceans. However, as we now know, within the global population there are subpopulations facing their own set of problems. Take for example the blue whales in the Northern Indian Ocean, the Unorthodox Whales, that I have been working with for many years – they are uniquely non-migratory, have a different vocal call, display different behaviors to other blue whale populations and face the threat of ship-strike and entanglement.

It seems that the largest animal to live on this planet that evolved with no natural predators has met its match in us humans and that is not something we should be proud about. We need to remember that no matter where we are, our impact on nature is huge, long-lasting and often indirect. While neither of us may have cast these nets in the water, they exist because of our dependency on fish and other ocean resources. Living consciously with an awareness for our every day impact allows us to better understand how we can help nature thrive and in return, help humans survive.

The net was trailing behind it causing the animal to move slowly - probably due to fatigue. Photo credit Tony Wu.
The net was trailing behind it causing the animal to move slowly – probably due to fatigue. Photo credit Tony Wu.
Marine biologist. Educator. Fuelled by curiosity.
  • Mary Finelli

    “While neither of us may have cast these nets in the water, they exist because of our dependency on fish and other ocean resources. Living consciously with an awareness for our every day impact allows us to better understand how we can help nature thrive and in return, help humans survive.”

    All of the nutrients derived from fish -and other animals/animal products- we can obtain more healthfully, humanely, and environmentally responsibly from plant sources. Respect life, including your own: Be vegan.

  • MG St John

    I agree with Mary, but for those still eating creatures from the sea, there are so many ways to return the gift of life they provide us. We feed our oceans garbage, yet expect it sustain us. Reducing water over-consumption from needless use(watering lawns and washing cars) and contamination of fresh water resources(lawn fertilizer, chemical disposal) helps preserve watersheds and reduce runoff to into the sea. Stopping the take of forage fish such as herring, menhaden, shad and alewife that are used for farm animal feed and cosmetics will help larger fish populations to recover by restoring their natural food sources. Our oceans are the real cradle of life on this planet and the stress we place on them bites the hand that feeds us and everything else.

  • gilbert k

    When it comes to marine life, human interference is the biggest hindrance

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