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Flickr photo: Epaulette Shark by richard ling
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Recent research suggests that when faced with suffocation, epaulette sharks are able to “turn off” electrical impulses to the eye and other parts of their nervous system to conserve energy.

The Life Oddquatic

There are a lot of weird things in the ocean. The Life Oddquatic is a feature about some of them. This week’s topic also satisfies my compulsory contribution to Shark Week.

A Monument to Their Ego and Ignorance

There is a short piece in the New Yorker about a psychiatrist and his second-story shark tank. The story brought back memories of many things I hated about working in a fish store. As a friend pointed out, many men who get a shark tank think they are getting it for the fish, but what they end up with is usually a monument to their ego and ignorance. Some choice excerpts from the article confirm my bias.

• » The pet shark may be the new pit bull—the mascot of the outsized ego, the Hummer of the living room.
• » The fish, a blacktip reef shark, was caught in Indonesia six months ago and supplied to Saul by his longtime fish guy (“I found him through my stereo-system guy”).
• » The shrimp were for three eels, hidden among rocks on the tank’s floor. “Do you see where the eel has a scar?” Lynn asked. “The shark is biting it.”
• » It’s going to be awesome when we get another two sharks in there

Based on these details, I have serious doubts about the future of these animals. When I worked in a fish store we would not sell requiem sharks (Family Carcharhinidae). I wish I could say it was a decision motivated by conscience instead of economics. But the fact of the matter is, requiems like the blacktip reef shark rarely do well in a store or in a hobby home. They require hundreds of gallons of swimming space, eat expensive food (or expensive tank mates) and are especially skittish, slamming themselves to death against tank walls when spooked.

Today, if someone insists on keeping a shark, I insist that they first read Aquarium Sharks and Rays by Michael W. Scott. Scott does a pretty thorough job of describing which species do better in captivity, recommending the bamboo and epaulette sharks (Family Hemiscylliidae) as the more suitable. But the Hemiscylliids are not your classic looking shark. They are elongated, almost serpetine, resting on the bottom and “walking” around on the sea floor. They are also comparatively small (107 cm or 3’ 6”) and their natural habitat is the confined crannies of tidepools and coral reefs. A knowledgeable hobbyist would recognize that these characteristics of a Hemiscylliids are better for acclimating to a life in captivity than the free-swimming, streamlined lifestyle of a Carcharhinid.

Another recent and amazing adaptation detailed on the Discovery Channel’s Web site is the ability of some Hemiscylliids to “turn off the electricity” to avoid suffocation. Since these animals live in shallow waters, they often encounter hypoxic conditions (low oxygen levels). Researchers determined that under these conditions, the sharks turn off electrical activity to their eyes, effectively going blind. It is probable that the sharks also shut down other parts of their central nervous system as well.

Despite all of these remarkable adaptations of the Hemiscylliid, I would still counsel against owning a shark as a pet. Perhaps the carelessness and callousness that I witnessed in my fish store daze has jaded me. But I’d rather see these creatures in the sea than on the streets of the Greenwich Village.

More Shark Week in the Blogosphere

• Discovery Channel: Sonja Fordham blogs about shark conservation for Shark Week 2008
• Water Notes: Shark Perception, Not the Ampullae Either
• Malaria, Bedbugs, Sea Life and Sunsets: Get Sharked!