Whale Magazine :
Caring, Sharing False Killer
by Tori Cullins
Does Longline Fishing Threaten Hawaii's False Killer Whales?
We were about 1/2 mile off the coast of Oahu when a false killer
whale (Pseudorca crassidens) offered to share its lunch with
us. It was one of those magical moments when humans become part of
the cetacean world. On a boat bearing a group of middle-aged woman,
table manners weren't the only thing we had in common. Some of the
females in this particular group of false killer whales have also
been through menopause. Being fairly long-lived, the "change of
life" begins in female false killer whales at about the same age as
it does in humans, at around 45 years old. "Textbook"
menopausal females may take on the role of a grandmother,
babysitting and teaching younger members how to hunt and behave amid
the tropical and temperate oceans in which they live. However, we
prefer to think that, similar to us, "Tutu"
(endearing Hawaiian term for grandmother) is kept around for her wisdom. Though unlike our own floating group of experienced women, this Tutu isn't sticking her head in the freezer to cool off, nor finding that chocolate has become a necessity.
Our pleasant, wet, companion at the length of 17 ft. (males can get up to 20 ft.) exceeds the combined weight of us six ladies. She seems to think that perhaps we have had too much chocolate and should switch to the sashimi of which she is so fond. We like sashimi also, but the very raw tuna she is offering has little flesh left and is mostly head, fins and some trailing innards. Hmm... uh, no thanks? She has already made the rounds of offering chunks to fellow pod mates and before finishing it off herself, she has thought of us. Sweet, but sad.
Like Orca, false killer whales are top predators. Being at the top of the food chain, both of these distant cousins accumulate high levels of toxins. Amazingly (given that it's been banned over 35 years ago), DDT has just begun to show up in Hawaii's false killer whales. Plastic particles containing harmful chemicals such as PCBs and DDEs have been ingested, and can also cause intestinal problems. Reproductive-system damaging
fire retardants have recently been found lurking in false killer whale biopsy samples. As "Tutu" finishes off the desirable tuna cuts, she discards the waste, leaving it for the ocean scavengers. Seems like a wise move, grandma. We are glad that with increasingly diminishing fish sizes in Hawaii (from overfishing), that this tuna was large enough to share.
Despite their name, false killer whales don't look like true killer whales. They are slender, mostly black and lack the dorsal fin height of their famous namesakes. Their genus, Pseudorca, comes from similarities in the skull and teeth. Similarly, both "killers" are uncommonly seen, long-lived - aging
well into their 60's, slow to mature (teens), and
have long intervals between births. The biggest difference may be that while Orca are quite popular, most folks have never heard of the false killer whale. In Hawaiian waters we have two populations of false killer whales. The isolated
near-shore residents who are truly native - they are the only genetically distinct population of false killer whales in existence. The other roving, or pelagic, false killer whale population usually stay well offshore. While their ranges overlap, there is little interaction between the two.
Over the past thirty years, this near-shore population has been reduced by about one third of the size first recorded in the late 1980's. The current population is estimated at only 123 individuals. This is the smallest population size of all of the 18 species of toothed whales and dolphins found in Hawaii.
With their gregarious antics, social charm, and calming presence, we've been FKW fans for many years now. Sometimes our first clue that false killer whales are in the area is to have a mahi-mahi or tuna rush the boat, seeking refuge around or between our hulls. Scan the ocean surface and soon you will see the characteristic "push" of water, spraying forward and upward as FKW semi-clear the water in pursuit of prey. Most dolphin tend to keep their heads below the surface, revealing only their blowhole, backs, and dorsal fins. Not so for this species!
Cooperatively hunting their prey, a group of varying ages glide into view, bouncing click trains off the bottom of the boat. The panicked yellowfin tuna comes out of hiding to dart frantically from one side of the boat to the other.
Finding no refuge, it dives deep and is easily followed by a senior member of the pod. She returns to the surface and explosively clears the water, with the mahi-mahi draped over her lower jaw. It is stunned into stillness, but unhurt. She places it before her calf, it is his turn to mimic his mother's skills. When the released fish regains it wits, the game resumes. When the calf has had enough practice, the fish will no longer be released.
Based on satellite tagging of the species, at least once a month they seek food far enough offshore to become caught on the hooks of longline fishers. As the name implies, hundreds or even thousands of baited hooks can hang from a single line that is miles long. It's hard for any hungry sea creature to resist the smorgasbord present on these lines, dolphins, whales, seabirds or even endangered sea turtles. The eruption of longliners in Hawaiian waters in the later 80's marked the beginning of serious decline of our false killer whale population.