Shaw’s Cowfish are found to inhabit sheltered and moderately exposed coastal reefs and deeper parts of large estuaries, along Australia’s south coast (Dongara, WA to southern NSW and around Tasmania) from depths of 10 to 160 metres. Sexually dimorphic fishes, the males and females differ substantially in colour pattern, with males ornamented with irridescent bright blue and yellow and females being more spiny with horn-like protrusions showing a pattern of scribbled orange, black and white markings over the body. Shaw’s Cowfish feed on a diet of small invertebrates and seaweed, by blowing a jet of water at sediments and feeding on what becomes dislodged. Mature specimens grow to a maximum length of 25 centimetres.
Similar to the wrasses, juvenile Cowfish join a female harem. Here, there is a single dominant female, however all are under the control of a single male Cowfish. If the male disappears from the group, the dominant female of his harem will change sex and become the new dominant male.
Other common names include Striped Cowfish.
Occurrence at the Busselton Jetty
Female Shaw’s Cowfish are commonly observed around the Underwater Observatory, where they are often seen feeding on the concrete ledge around the base of the Observatory. They can also be sighted swimming up around the jetty piles. Male Shaw’s Cowfish are only sighted occasionally, being that their numbers are much less than their female counterparts.
Image by: A. Brown