NOWRAMP 2002

Creature Feature - Spotted Knifejaw

It's alive!

Just two days into our journey and we have encountered a number of interesting organisms.

Spotted Knifejaw
Oplegnathus punctatus (Temminck and Schlegel, 1844)

Although knifejaws are rare in the main Hawaiian Islands, the dive crews have begun encountering large individuals. A two- foot long knifejaw is hard to miss. They are usually observed as solitary animals or found in small groups. The strong, intimidating teeth of these fish are actually used for crushing mollusks, barnacles and other hard shelled animals. They may also eat some seaweeds.

The knifejaw family (Oplegnathidae) has an interesting distribution. They are not tropical, but anti-tropical. Look up the following places on a map and note the pattern: knifejaws are found in South Africa, South Australia, Japan and Hawai'i, the Galapagos Islands and south to Chile.

On this trip so far, we have seen these fish at Nihoa and Mokumanamana (Necker). We expect to continue to encounter them as we move up the chain.

Information from: Shore Fishes of Hawai'i, John Randall, 1996 and Alan Friedlander.