Mimic Goatfish with Bluestripe Snappers (Nuku Hiva, Marquesas)
Mulloidichthys mimicus (Randall & Gueze, 1990)
In late October 2004, Alden Takata was fishing off east Kaua`i when he caught something he'd never seen before--a weke (goatfish) that looked like a ta`ape (Bluestripe Snapper). Biologists from the Hawai`i Dept. of Land and Natural Resources identified the fish as Mulloidichthys mimicus, a goatfish previously known only from the Marquesas and Line Islands. This unusual goatfish looks just like the Bluestripe Snapper (Lutjanus kasmira), and in fact mimics it. Both species rest in schools by day; in the Marquesas and Line Islands they mix and are almost indistinguishable. The best way to tell them apart is to look at the back edge of their tail fins: almost straight in the snapper but forked in the goatfish. (Can you tell the two apart in the photos above and below?) The goatfish generally keep their telltale barbels tucked up and out of sight, but see the photo at bottom of page. Why do the goatfish mimic snappers? Scientists speculate that predators may find the goatfish tastier or easier to catch than the snappers, thus the goatfish survive better by disguising themselves as snappers and hiding among them. So far, only one Mimic Goatfish specimen has been found in Hawai`i. Divers and snorkelers, if you see one try to get a photo and contact the Ichthyology Dept. at the Bishop Museum with the details. In case you are wondering, Mimic Goatfish are not (yet?) recorded from Johnston Atoll, which is much closer to the Line Islands than is Hawai`i and would make a logical steppingstone. They attain about 12 in. and are endemic to the Marquesas and Line Islands. Photos: Nuku Hiva, Marquesas.
Mixed school of Mimic Goatfish with Blue Lined Snappers (Nuku Hiva, Marquesas)
Mimic Goatfish showing barbels at a cleaning station (Nuku Hiva, Marquesas)