False Killer Whales Foraging

The PWF research team left Lahaina at our usual time of 8 am on Thursday, August 23, 2012.  Our day kicked off with excitement as it was our first day aboard Ocean Protector, our new research vessel.  After fueling we headed out to complete our next randomized transect lines through Maui County waters in hopes to learn of dolphin abundance and distribution. 

We had just started off by completing one transect line when we saw dorsal fins cresting the surface.  About 30 Spotted dolphins appeared out ahead of us.  We instantly realized this was similar to the location we last sighted Spotted dolphins.  Enthusiasm spread with the idea that we may have just learned an important aspect of Spotted dolphin distribution.  We hope to see Spotted dolphins in that area again!

We continued our transect lines, with no idea what the day would bring.  We were finishing up our fifth transect line and what luck…our next encounter was with False Killer Whales!!!  The insular population of FKWs has reached numbers as low as 123 (Baird 2009-see below) and Pacific Whale Foundation has been part of the effort to get these amazing animals listed as an Endangered Species.  Our research team estimates we experienced 20 of these beautiful FKWs today (16% of the estimated entire population).

I should mention that to see a False Killer Whale is invigorating solely due to the fact that their numbers are so low.  However our encounter with this pod surpassed any that a researcher could ask for.  FKWs were leaping out of the water chasing mahi mahi!!  If you look at the pictures, you can see airborne FKW and “dolphin-fish” (as mahi mahi are also called).  To see this struggling species foraging is great but to see them soar out of the water pursuing a large fish with birds swooping down to steal chunks of fish was beyond expectation.  A small group of four FKWs caught a fish and through the crystalline water our team witnessed them swim under our vessel passing a hunk of fish back and forth.  FKW are known to share food within their social groups.  There have even been stories of the offering fish to humans!  We were also lucky enough to witness a mom and its young!  To see a new addition to this small population learning to hunt prey with its mom was breath taking.

It was time to continue our transect lines, but as we left, one FKW decided to bow ride Ocean Protector.  This individual stayed with us for nearly 20 minutes allowing us to get some great photos of scars on its body.  We can’t say for sure what was the cause of these scars, however the leading threat to FKWs in these waters is interaction with long-line fisheries.  Perhaps this was one of the FKW that had interacted with a long-line but survived the encounter.

At this point, the research team had collected as many dorsal fin photos as we could.  As we head back to the lab, we look forward to comparing these identification photos against our current catalog of 71 individuals.  Though it would be great to match a dorsal fin against already existing sightings of an individual to continue its life story, it would be even more phenomenal to add new individuals to our catalog.

Everything about this day involved ingredients for an amazing day of dolphin research, but fate would have us also encounter a pod of Spinner dolphins before the day was through.  Overall, I’d say we learned a lot regarding abundance and distribution of dolphins in Maui County waters today.  Along the way we were also reminded that days like these are why many of us chose this as our career path.