Dynamic colour change as a signalling tool in bluelined goatfish (Upeneicthtys lineatus)

We explored dynamic colour change in the bluelined goatfish Upeneichthys lineatus, a temperate marine teleost species. Upeneichthus lineatus 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 U. lineatus 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 U. lineatus were collected to (1) document the repertoire of behaviours that U. lineatus displays and categorise associated colour patterns; (2) quantify the speed of dynamic colour change; (3) establish the context in which U. lineatus 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 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 U. lineatus 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). 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.本研究针对蓝纹羊鱼（Upeneichthys lineatus）的动态体色变化展开探究。蓝纹羊鱼是一种温带海洋硬骨鱼类，可在数秒内完成体色转变，从通体均匀的白色变为带有醒目垂直暗红色条纹的体色。初步观测显示，该物种的快速体色变化与觅食行为存在关联，且可能作为信号传递给同种个体与异种个体——此前已有大量观测记录显示，诸多鱼类会跟随觅食中的羊鱼活动。为达成相关研究目标，本研究通过收集蓝纹羊鱼个体的体色与行为野外观测数据，旨在实现以下四项研究内容：(1) 记录蓝纹羊鱼的行为谱，并对其伴随的体色模式进行分类；(2) 量化动态体色变化的速率；(3) 明确蓝纹羊鱼改变体色与体色模式的具体情境；(4) 验证跟随鱼类的行为是否会受到目标羊鱼的体色图案或特定行为的影响。本研究采用水肺潜水（SCUBA）的方式，对35尾蓝纹羊鱼个体开展单次时长3分钟的追踪与录像记录。录像工作在澳大利亚悉尼的温带海域进行，该区域为蓝纹羊鱼的典型栖息生境，水深范围为5至10米，具体观测点位包括：戈登湾（Gordons Bay，南纬33°54'56.66''，东经151°15'47.26''）、贝壳滩（Shelly Beach，南纬33°48'0.36''，东经151°17'47.31''）以及巴尔岛（Bare Island，南纬33°59'29.17''，东经151°13'59.25''）。每间隔5秒，即记录一次目标羊鱼的行为、体色以及所处的底质环境。同时，本研究还对主动与目标羊鱼互动或跟随其活动的跟随鱼类进行物种鉴定记录，并记录这些跟随鱼类的行为，若存在相关信息则同步记录其体色特征。