And you thought tuna and swordfish were toxic mercury bombs? Next time in Tokyo, avoid the whale and dolphin sashimi—creepy delicacies that Japan insists on consuming despite international opprobrium. Scientists at the University of Hokkaido have measured what New Scientist (June 2) calls "astonishing levels of mercury" in dolphins and small toothed whales (which aren't protected under an international whaling ban that Japan circumvents anyway).
Mercury is widely used (and discarded) in batteries, switches, thermostats, fluorescent bulbs, and dentistry. It's also a potent neurotoxin that can disrupt growth and reproduction and, in the right form and dose, kill. The mercury used in making felt caused brain damage in old-time hatmakers, inspiring Lewis Carroll's Mad Hatter and the enduring phrase "mad as a hatter." The Hokkaido researchers found one to 80 parts per million (ppm) of this pesky metal in whale muscle samples—2.5 to 25 times the legally consumable limit in Japan. Lung and kidney tissues averaged about 40 ppm and ranged four times that high. And whale livers, a true delicacy, averaged 370 ppm; one was packed with 1,980 ppm, nearly 5,000 times the Japanese limit.
At that concentration, one two- hundredth of an ounce of liver would exceed the weekly mercury intake the World Health Organization deems safe. Eating any animal's liver seems reckless these days—kids are smart to say "yuck"—but these levels are literally mind-blowing.
Activists will doubtless exploit these findings to try to get Japan and other whaling nations to lay off.
What about the local whales? Sorry, Sea Shepherd; the gray whales the Makah Tribe occasionally kills aren't so mercurial. Grays forage much lower on the food chain—little sedimentary crustaceans called amphipods—than dolphins, which favor high-mercury squid and bottom fish. And diet is a main determinant, along with longevity, of how much mercury and other "bio-accumulative toxins" animals store. John Stein, conservation director at the federal Northwest Fisheries Center, says gray-whale livers have shown less than one-half part per million of mercury. Likewise those of another giant, the copepod-eating bowheads that some Alaskan natives hunt.
And what about the killer whales that local TV stations have lately hunted so zealously? The conventional wisdom is that, as People for Puget Sound's Pam Johnson put it, "mercury is not a problem" in orcas.
But that merely reflects lack of data. Killer whales are really just very large, long-lived dolphins and top-of-the-chain predators. Trouble is, says Stein, when they die, they tend to sink, rather than washing up for convenient autopsying. Researchers do take blubber biopsies, which show whopping levels of toxic PCBs. But mercury and other metals collect not in the blubber but in the brain, liver, and other organs. And it seems likely that they're collecting big-time in orcas' organs. "I'd be surprised if their [mercury] levels were a lot lower than the dolphins'," says Stein. One badly degraded orca liver that the feds did manage to test measured "more like a dolphin than a bowhead" in mercury.
All this suggests that researchers should consider one more deadly poison—a toxin that pulp mills, instrument makers, and other industries pumped out for decades—as they try to unravel the mystery of the local orcas' sudden, steep decline. Is Springer at risk for mad hatter's disease?
GOODBYE, MS. SRI
Another animal celebrity left the local scene last week when Sri, Woodland Park's other potential elephant mom, was sent off to breed at the St. Louis Zoo. The July 9 loading apparently went smoothly, despite dire warnings from animal advocates that Sri would freak out when she got dragged aboard the truck. And since this truck was air-conditioned, Sri shouldn't get as hot and dehydrated as her barnmate Chai did when she was trucked to Springfield, Mo., for breeding three years ago.
Sri, the bottom elephant in the Seattle herd's pecking order, may get along better with her new companions than Chai, who stayed apart from the Springfield herd. After Chai delivered baby Hansa, Sri and the older Bamboo became odd elephants out. While the main room, keepers' attention, and outside access were devoted to mom and baby, Sri and Bamboo were confined in small side chambers of a barn that, though fairly new and very costly, wasn't designed for family groups. Sri, always nervous and restless, grew even more so. She doggedly peeled away patches of floor despite keepers' attempts to stop her by smearing (elephant) feces on them.
It's a dicey business, breeding these smart, sensitive, idiosyncratic animals, with their deep attachments and complex relationships, and shipping them around like, well, chattel. Sri is leaving the only home and companions she's ever known. On her last afternoon in Seattle, with no one else around, I saw her lean into Bamboo, who wrapped her floppy lips and trunk around Sri's head in the sort of full-face kiss only elephants can give.
Good luck, big girl.
Eric Scigliano's environment column appears every other week.