Competition between mullet fry

The fry of Liza ramada, L. aurata, L. saliens, Chelon labrosus and Mugil cephalus in a lagoon in NE Spain fed mainly on zooplanktonic crustacea, such as cyclopoids, calanoids and cladocerans, but adult chironomids were also important. A high trophic and temporal overlap was found between the fry of several of these species. Trophic overlap was asymmetrical for almost all the species pairs and niche breadth expanded for the less competitive species when they were alone in the estuary. In contrast, niche breadth did not expand for the most competitive species ( L. ramada ) when it was alone. These results suggest that competition was occurring among these species, but experimental evidence is needed to prove its existence.