Fish of the Month: Hawaiian Morwong Goniistisus vittatus

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FISH OF THE MONTH - NOVEMBER 2005

HAWAIIAN MORWONG
Goniistius vittatus

Hawaiian Morwong - Midway Atoll. 30 ft.

MORWONGS (Family Latridae)
Morwongs are an unusual and sometimes comical-looking group of fishes found in subtropical and warm temperate seas. Their high, laterally compressed bodies are typically marked with bold black diagonal bands and their small mouths have thick fleshy lips. Bony knobs often protrude in front of the eyes. Morwongs are related to hawkfishes, and, like hawkfishes, many species have thickened pectoral fins which allow them to sit upright on the substrate. They typically feed on small crustaceans and other invertebrates found in sand. Occurring from South Africa to the Pacific coasts of Peru and Chile, morwongs attain their greatest diversity in the cool waters off southern Australia (hence the distinctive aboriginal name). Above the equator they occur in Japan, Korea, China, and, of course, Hawai`i. This type of distribution, known as "anti-tropical," is characteristic of a number of Hawai`i's fishes. Although morwongs were formerly placed in their own family Cheilodactylidae, ichthyologists have recently combined them with the trumpeters (a small group of exclusively south Australian fishes) into the single family Latridae. During this shakeup, they changed some genus names as well, including that of our Hawaiian species, which used to be Cheilodactylus vittatus.

Hawaiian Morwong - Midway Atoll. 30 ft.

HAWAIIAN MORWONG · kikakapu
Goniistius vittatus (Garrett, 1864)
These odd fish have thick reddish lips and bold diagonal black stripes which may serve to disrupt their outline or to make them appear extra-large to predators. Bony lumps and bumps adorn the front of the head. They often prop themselves on the bottom with strong pectoral fins, somewhat like hawkfishes. Unlike hawkfishes, however, they appear to be nocturnal and are probably resting rather than waiting to ambush prey. They feed by pressing their thick fleshy lips to the bottom, sucking in sand and detritus, and filtering out the small invertebrates it contains. (While feeding this way, some morwong species are known to almost stand on their head!)
Although common at Midway and other cool, subtropical Northwestern Hawaiian Islands, morwongs are rare in the main islands. Divers on Kaua'i and along O`ahu's north shore have perhaps the best chance of seeing them. (I like to tell people that if they see a morwong, they will enjoy one year of good luck!) The Hawaiian Morwong is now considered endemic. Previously it was lumped together with a similar species from the subtropical South Pacific islands of New Caledonia and Lord Howe. Morwongs share their Hawaiian name ("strong kapu") with several butterflyfishes. The species name means "striped." To 16 in.

Here are two of the very few Hawaiian Morwongs I have seen in the main Hawaiian Islands.The one above was at snorkeling depth inside the reef at Hanauma Bay, sitting under ledge in the area known as "Sandman's Patch." It stayed in the vicinity for a few weeks and then disappeared. Below is a cute baby about 3 in. long, seen in about 3 ft. of water at Lydgate State Park, Kaua`i.

Below, a morwong altercation at Midway. The bottom fish appears to be chasing the top one. Note how several of the black bands have paled near the top of the head of both fish, revealing a spotted pattern. This appears to be morwong-speak for "get out of my territory" or "leave me alone." But who knows? Perhaps it means "Come here my darling." We need more divers observing morwongs.