Adventures in camera trapping and zoology, with frequent flashbacks and blarney of questionable relevance.
Monday, September 17, 2007
Dead whales, gawkers, and scavengers
[Photo: Stephen Osman / Los Angeles Times]
A Blue whale made quite a stink and drew a fabulous crowd last week. Highway 101 beside Ventura's Solimar Beach was jammed as the masses clamored to the sand. Folks down there don't see much wildlife, and a beached whale is a once-in-a-lifetime experience anywhere in the world. Well, I take that back. A smaller blue whale was cast ashore on Long Beach a few weeks ago. It seems these leviathans made the fatal mistake of tarrying in the shipping lanes of the Santa Barbara channel, where whale food seems to be concentrated this year. The latest word is that the vets who performed the necropsy went home to bathe, and the carcass was buried by dozers.
Which makes you wonder. Are there marine scavengers suitably sized and equipped to dispose of this amount of putrescent mana? You know, not all whale, giant shark, and megasquid corpses come to rest on a beach or rocky shore, do they. Most of them, I imagine, linger in the deep blue sea like de-finned sharks. In the Pleistocene there was a fine assemblage of terrestrial scavengers here, including California condors, to fight over beached spoils, and we know that large cats stomach foul meat quite well. I can see Felis atrox and Smilodon fatalis following their noses to the beach.
What I want to know is this: are there any large marine scavengers in the briney deep? Or are colossi of carrion nibbled away by bacteria and gazillions of marine invertebrates? If someone in the blogosphere has the answer, please fill us in!
I guess it's just coincidence that Martin Collinson's blog -- George Bristow's Secret Freezer recently evoked a whale memory of my bygone youth. This moved Martin to do me one better in the category of tales of bawdy biologists.
I might add that as I was flensing that grampus, something moved me to smack the whale's mellon (the bonnet of fat) with the side of a machete. The purest of clear oil oozed forth, which I collected in a jar like some precious liquor. That night I lovingly rubbed the whale oil into the leather sheath of my skinning knife. It soon turned black and mellowed into the overwhelming and unmistakable smell of rancid whale oil. It was the gift that keeps on giving. Anything stored in my skinning kit (an old metal tackle box) acquired the bouquet. I kept it in the basement, and ten years passed before I discarded the sheath. Twenty years later I tossed the metal tackle box, but I still have the knife and its delicate bouquet to remind me of dead whales.
Thanks to Marty Fujita of Marty's Food Chain for setting the wheels in motion for this story.
I've seen some cool videos, including one called Blue Planet, that chart the whale decomposition process in deep water. For the Blue Planet series they towed a dead Gray Whale out into the Monterey Sea Canyon and sank it with an attached sonar beacon in about a mile of water. Within a short period of time, hagfish (http://en.wikipedia.org/wiki/Hagfish)were all over the thing, as were some huge, slow-moving deep water sharks like a sleeper shark (http://en.wikipedia.org/wiki/Pacific_sleeper_shark) There were also smaller creepy crawlies eating on the carcass.
ReplyDeleteThe really cool thing, though, is what the carcass looked like after a year. There were still a few hagfish getting bits and pieces of flesh clinging in the recesses of the skull, but the whale was mostly skeletonized. An outline of its body on the sea floor was made of a fuzzy bacterial mat, and bacteria were colonizing the bones.
I've read some articles suggesting that whale skeletons act as chemical food reserves on the featureless abyssal plains for chemosynthetic bacterial colonies, and maybe other invertebrates that live on the bacteria such as tubeworms. This could help explain how these organisms make it from one hydrothermal rift community to another, since active hydrothermal venting is probably ephemeral and new vent communities seem to establish themselves relatively quickly in areas very distant from other active hydrothermal venting areas. Just as various terrestrial organisms have island-hopped throughout various ocean basins, chemosynthetic bacteria and the organisms that depend on them might use whale carcasses to lessen the gaps between suitable hydrothermal vent habitats.
Not too technical, but check out this article, especially the section on "carcass" and the pictures of the whale fall.
ReplyDeletehttp://www.signonsandiego.com/news/science/20070322-9999-lz1c22whales.html
Very interesting article. I heard Estes at the mammal meetings at Arcata a couple years ago, but whale decomposition wasn't on the program. Wish I had an excuse to write about hagfish, fascinating but creepy creatures. If I could get a picture of a lamprey in a coastal river here, I'd have a good excuse. Thanks, Bill.
ReplyDeleteThis reminded me of the infamous whale beaching in Oregon many years ago. It lay there for some time, slowly decomposing, while authorities figured out what to do. Finally, someone had the brilliant idea that if they planted explosives around it, and blew the carcass into small pieces, the tide would sweep it all back into the sea. Problem solved!
ReplyDeleteSo they blew up the whale. Unfortunately, all they did was blast large chunks of putrid whale flesh everywhere. One very large piece flew into a parking lot near the beach and smashed a car. I've always wondered how he explained the damage to his insurance company.
John Mikes
Officer Bob's Bird & Bug Emporium
Thanks for bringing that up, John; I have a vague recollection of hearing that story. Yeah, it's hard enough getting the insurance companies to pay up for the ho-hum everyday stuff, let alone flying whale carrion.
ReplyDeleteCalifonria Grizzlies also feasted upon beached whales. What a site that must have been
ReplyDeleteDR
I just returned from a short trip to Santa Cruz Island. Crossing the Santa Barbara Channel on 9/18, we had a rare sighting of what appeared to be a Minke whale. We also came across a large pod of Pacific Bottlenose dolphin. The return trip on 9/20 was even more spectacular: we traveled through a nursery pod of dolphins (about 200) each with small baby swimming very dlose by (one adult even had twins!). About 20 minutes before arriving into VEntura Harbor, we came across a dead blue whale, floating belly up with seagulls perched on top. Very sad since this is the third dead blue in two weeks in the area. We watched as about 6 blue sharks (each about 5 to 8 feet long) took bites out of the whale's sides. Out of nowhere, a huge shark came out of the water and hoisted itself onto the whale's belly nearer the flukes. This shark had a white underbelly and looked to be about at least 10 feet long. We all speculated that it was a great white, and judging from the sizable chunk of flesh it extracted as it slid back into the water (about 20 to 30 cm at widest part of bite), i'd say it could have been. It looked and acted much differently than the other blue sharks.
ReplyDeleteI wonder what is going on with all these dead blues. The profound sealife in the Channel right now is probably there because of the big upwelling event that occured recently. Folks in the know estimate that there are about 0 blue whales in the area, and that they cannot avoid the large number of huge tankers and freighter that ply the Channel. But I really wonder...is domoic acid affecting their ability to detect these large (and presumably noisy?) ships? Maybe hearing damage from Navy sonar? So sad. But a spectacular display of sealife and the bounty of nature in these waters.
I'll try to get photos of the sharks feeding. I, alas, did not have my camera, but i know others onboard got the shots.
Marty Fujita
Thanks a lot, Marty, for those neat observations. Would love to see the pictures, and hope you get a new digicam before your next trip.
ReplyDeleteJust back from some travel and catching up on your blogs. Great reading, as usual. Re. whale carcasses, I remember reading somewhere (old age precludes remembering where exactly) that as the behemoths die, they settle to the bottom of the ocean, where there is an entire ecosystem that subsists off of them (crabs, worms, etc.). I do remember that the author of the story had some questions of his own – like how do these critters disperse between carcasses, which are likely quite widely spaced. In any case, it’s it yet another example of how powerful natural selection is – where there are resources, some critters will evolve to exploit them!
ReplyDeleteI don't know about "large marine scavengers in the briney deep?" but Nova I think it was (or maybe Blue Planet, yeah) once showed a whale sinking to the murky depths, and it being subsequently consumed by hagfish of all things. Apparently, there are quite a few at the bottom, and they come from near and far at the scent of submarine carrion. Maybe they deal with the big stuff (together with other detritivores such as sharks and etc.), and the bacteria are left the rest? I would think that bacteria could not function too too well at depth, though, as the temperature is ca. 4ÂșC: certainly not optimal for bacterial decomposition.
ReplyDelete