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The following paper is available.� Please feel free to contact me ([EMAIL PROTECTED]) for a PDF. Amorim et al. (2004). Sound production during competitive feeding in the grey gurnard. Journal of Fish Biology 65, 182-194 abstract The acoustic repertoire of captive grey gurnard, Eutrigla gurnardus, during competitive feeding consisted of three types of sounds: knocks, grunts and growls. Knocks were audible as a single sound, whereas grunts and growls were perceived as longer, pulsed sounds to the human ear. Typically, knocks were composed of 1-2 pulses, grunts of 4-8 and growls of more than 10 pulses. Growls were longer and had shorter pulse periods than grunts. All sound types had peak frequencies around 500 Hz. The sequences of behaviours observed during feeding interactions suggest that grey gurnards obtain food both by scramble and contest tactics. Competing fish emitted knocks mainly while grasping a food item, and also during other non-agonistic behaviour, suggesting that knock production may reflect a state of feeding arousal but could also serve as a warning of the forager's presence to nearby competitors. Grunts were mainly emitted during frontal displays, which were the most frequent behavioural act preceding grasps, suggesting that they may play a role in deterring other fish from gaining access to disputed food items.
