Host selection, location, and association behaviors of anemonefishes in field settlement experiments

Abstract

Nine anemonefish species were reared in the laboratory, and individuals were released in the field (Lizard Island, Australia and Madang, Papua New Guinea) at different distances and orientations away from natural (anemone species the fishes are found with in nature) and unnatural species of host anemones. Experiments were conducted to examine factors that could affect the settlement behaviors of the fishes: current velocity, distance and orientation of the fishes to the anemones, chemical vs visual cues, and presence of conspecific or heterospecific fishes. The fishes were usually attracted toward natural host species of anemones but not towards unnatural host anemone species nor to pieces of dead coral. Host selection during settlement provided the best explanation for the host specificity patterns displayed by anemonefishes in nature. The fishes used chemical cues released from the anemones to identify and locate the appropriate host species and could effectively locate the anemones from a maximum distance of 8 m downstream. Fishes released upstream or to the side of anemones (where anemone chemicals were assumed to be reduced or absent) were much less successful in locating anemones. The ability of the fishes to locate natural host anemones was strongly reduced when there was no water current. The presence of resident anemonefishes on host species of anemones did not influence the attraction behavior of anemonefishes released downstream from the anemones. Once the released fishes got close to or entered the anemones, the resident fishes would generally bite and chase them until the recruits left the anemones. Most fishes were not stung upon initial contact with the anemones.