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Ocean Watch

By Susan Scott

Monday, July 3, 2000

This season,
beware catfish
scratch fever

Catfish made the news last week when their fishing season opened at Nuuanu Reservoir. These odd-looking fish aren't native to Hawaii; the state imported them from the mainland in the late '60s.

But are catfish native there? I wondered.

They are. And they're native to just about everywhere else in the world, too. Over 2,000 species of catfish inhabit the fresh and salt waters of Central and South America, Africa, Europe, Asia and Australia.

Catfish get their name from their whiskers, which are actually taste organs called barbels. Our familiar goatfish also have these whiskery barbels, and both kinds of fish use them in the same way: They poke and probe the ocean or pond floor to find food. In the case of catfish, this is just about anything that falls to the bottom.

I once thought that catfish whiskers could sting you, but they can't. It's the spines on the back (dorsal) fin and the two front side (pectoral) fins that bear stingers.

Catfish use their venomous spines for defense only. When a catfish gets agitated, it extends its spines, locks them in place and waits. A frightened catfish strikes when a predator, including a human hand, comes within range.

Glands lining catfishes' sharp spines store venom. When the spine penetrates flesh, the glands rupture and venom trickles into the wound. No one knows the exact nature of catfish venom, but catfish handlers do know that it hurts like crazy.

The treatment for the pain of catfish stings is to immerse the hand or foot in hot water, then wash the wound and wait. The pain and swelling usually goes away on its own in a couple of hours to a couple of days. Catfish envenomations can sometimes cause later infections. If you get stung and have persistent symptoms, see a doctor.

We have two kinds of catfish in Hawaii: the American channel catfish, imported by the state in 1969 as a food fish, and the Chinese catfish, arriving with Chinese immigrants around the turn of the 20th century.

Channel catfish are the ones that people fish for in the Nuuanu Reservoir. Dennis Shinno, a state fish biologist, told me that these fish pack the biggest punch when they're small because the fin spines are still sharp and can easily penetrate human hands. When the fish get older, their spines get rounded off from rooting around the lake bottom and therefore don't pierce skin easily. Chinese catfish, grown in Hawaii aquaculture farms today, also inflict aching stings.

Shinno knows about catfish stings firsthand. Each year, he scuba-dives in Nuuanu Reservoir to collect fertile catfish eggs from nests the fish dig on the bottom. Because male catfish guard their nests, the biologists must divert the fishes' attention with a stick, then take the eggs quickly. These adult fish have dull spines so don't usually sting the workers, but they can and do bite.

In about 10 days, the eggs hatch into fry. Biologists feed and care for these young fish for six months to a year. If left in the lake, most baby catfish would be eaten by tilapia and other cichlids or starve to death. When the captive catfish are the proper size, they are released into the reservoir for anglers to catch.

Some people claim these nearly boneless fish taste better than salmon and trout. Judge for yourself. Look for catfish in the fish markets of Chinatown, or try catching your own. To get a catfish license, call the Department of Land and Natural Resources, Fishing Licenses and Permits, at 587-0109.

Or hang around Nuuanu Reservoir for the next few weeks. Maybe a lucky angler there will share.

Marine science writer Susan Scott's Ocean Watch column
appears Mondays in the Star-Bulletin. Contact her at

E-mail to City Desk

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