LAUSR

Mimicry is a commonstrategyamongcoral reeffishes that use diversemorphological features and behaviors to avoid predators or to increase successful foraging. Juvenile coral trout (Plectropomus spp.) strongly rely on coral habitat for food, shelter, andnurserygrounds (Wen et al. 2012) and have been hypothesized to mimic poisonous pufferfish. Coral trout Plectropomus laevis, P. leopardus, and P. maculatus are mimics of Canthigaster valentini and Canthigaster papua based on their color pattern, divergent diets, and ‘‘sculling’’ swimming behavior (Frisch 2006). These juvenile Plectropomus fishes might benefit by resembling the poisonous pufferfishes (Batesian mimicry) and by increased access to prey (aggressivemimicry).Here,we report another mimicry case of juvenile coral trout. Plectropomusmaculatus resembles juvenileScolopsis monogramma. Both inhabit shallow living Acropora coral in Great Keppel Islands, Great Barrier Reefs (Fig. 1a).Weobserved this juvenileP.maculatuswith similar body colorations as S.monogramma (Fig. 1b), including a greenish-gray body color, a distinct black stripe from snout to tail. In addition, this mimicry of coral troutalsodisplaysontogeneticchangesas inFrisch (2006),and theblackstripewasmuchclearerat3 cmTLthenstarted todisappear at 15 cmTL (Fig. 1c, d).We hypothesized that this juvenileP.maculatus individual displays aggressivemimicry of S. monogramma as the latter’s benthic crustaceandiet allows theirmimics to strike preygobids andblenniids. Similar cases of aggressivemimicmodelswere also recorded in Serranids, such as juvenile of Anyperodon leucogrammicus andHalichoeres leucurus, Mycteroperca tigris and Thalassoma bifasciatum (Randall, 2005). To our knowledge, this is the first report of juvenile P. maculatusmimicking S. monogramma; however, the actual mimetic relationship between these two species is still unclear. Further investigations of the behavior, relative abundance, and habitat preference of P. maculatus and S. monogramma are needed to verify these observations.