Friday, August 29, 2008

False Killer Whales In Danger Of Extinction?

On this day, we had some report on sperm whale, Physeter macrocephalus, sightings, so decided to go out far offshore to look for them. We cruised around all morning, and found some short-finned pilot whales, Globicephala macrorhynchus, but sperm whales were no where to be found. Just about we were getting inshore. We learned from our source that there were a small pod of false killer whales, Pseudorca cassidens, just off the Red Hill.

The false killer whale is a type of tropical dolphins. They are relatively large in size, growing up to 20 feet (6 m) in length and weighing up to 2.2 tons. They look similar to short-finned pilot whales, but can be easily distinguished by their smaller melon heads and more dolphin-like, slender dorsal fins. Their body colors seem also lighter than pilot whales, at least here in Hawaii, particularly young ones are.

false killer whale, Pseudorca cassidens, juvenile, Kona Coast, Big Island, Hawaii, USA, Pacific Ocean

As their name indicates, they are known to attack other mammals like smaller dolphins. Using their large bodies, they've been seen attacking a humpback whale baby, Megaptera novaeangliae, as well. This is one of the species I get nervous with when photographing underwater as they are big and toothy. I've seen them relentlessly attacking their prey (see this post: False Killer Whales Gang Hunting Lone Yellowfin Tuna). They can eat me alive easily if they really want to.

They live in tropical and subtropical waters around the world, but recently the Hawaii's population is severely declined. It is very shocking to learn the dramatic decline of the number of sightings in recent years.

false killer whales, Pseudorca cassidens, adult male with many scars, mother with fish (a jack) in her mouth and calf in background, Kona Coast, Big Island, Hawaii, USA, Pacific Ocean

Renowned cetacean scientist, Robin W. Baird PhD, presented a very sad facts on False Killer Whales in Hawaii at Cascadia Research Collective site, completed with a National Geographic Crittercam video footage and some nice pictures from my fellow photographer, Deron Verbeck, and local researcher and whale watch specialist, Dan McSweeney.

I've been contributing to his whale research around Kona by supplying photos and information of sightings as much as I can over the years, but in recent years, Robin elevated the urgency level on false killer whale research as he and other researchers learned or "felt" the severe decline in their population around Hawaii. He deployed a satellite tracking device on a whale and started getting very interesting information about their migratory patterns and frequencies of their visits to some areas.

After I read the article, I recalled that I used to hear a lot more about the false killer whale sightings in town. I've seen them several occasions for over a decade, but was only able to photograph them twice so far.

Apparently the commercial fishing like the notorious longline fishing is something to do with them as this method of fishing is known to kill many dolphins and sharks unnecessarily as bycatch, but no one concluded the definite cause to explain the sharp decline.

To be continued to: Spotted Eagle Ray - The Most Beautiful Thing I've Ever Seen!

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