Dynamic colour change as a signalling tool in bluelined goatfish (<em>Upeneicthtys lineatus</em>)

<p>We explored dynamic colour change in the bluelined goatfish <em>Upeneichthys lineatus</em>, a temperate marine teleost species. <em>Upeneichthus lineatus</em> can change in a matter of seconds, from a uniform white colour to display prominent, vertical, dark red stripes. Initial observations suggested that rapid colour change in <em>U. lineatus</em> was associated with feeding and may act as a signal to both conspecifics and heterospecifics that are frequently observed to follow feeding goatfish. Field observations of the colour and behaviour of individual <em>U. lineatus</em> were collected to (1) document the repertoire of behaviours that <em>U. lineatus</em> displays and categorise associated colour patterns; (2) quantify the speed of dynamic colour change; (3) establish the context in which <em>U. lineatus</em> changes colour and pattern; and (4) test whether the behaviour of follower fishes is influenced by colour patterning or specific behaviours of the focal goatfish </p> <p>We followed and filmed 35 individual bluelined goatfish in three-minute sessions on SCUBA. Recordings were made at depths of 5 - 10 metres at temperate locations in Sydney, Australia, where <em>U. lineatus</em> occur regularly: Gordons Bay (33° 54' 56.66'' S, 151° 15' 47.26'' E), Shelly Beach (33° 48' 0.36'' S, 151° 17' 47.31'' E), and Bare Island (33° 59' 29.17'' S, 151° 13' 59.25'' E). </p> <p>The focal goatfish behaviour, colour and the underlying substrate was recorded at each five second interval. We also recorded to species any follower fish that were actively interacting or following the focal fish. Also recorded was the behaviour, and where relevant, the colouration of the follower fish.</p>