Reproductive synchrony in a temperate damselfish, Chromis limbata

Synchronous reproduction has been reported in many tropical damselfishes, and it appears that temperature is the main driver of synchrony at these latitudes. However, reproductive synchrony and its relation to temperature is less well understood in temperate damselfish. The endemic Azores chromis (Chromis limbata) was chosen as a study species to address this topic. First, an ethogram of the reproductive behaviour and embryo development of the Azores chromis is provided. Then, are investigated (1) the reproductive dynamics at the colonial and inter-colonial levels, (2) how these are affected by temperature, and (3) the relation between reproductive dynamics and the social organization of temperate damselfish. In the Azores chromis, reproduction was cyclic with a high periodicity of 7.2 +/- 0.63 days on average. Embryo development was synchronous within colonies towards the beginning and the end of incubation, but not at intermediate stages of development. Colonies that were closer were more synchronized than those located further apart, despite contrasting temperature and depth profiles. Embryo size differences were also greater between colonies that were further apart, and embryos tended to grow larger in warmer water. A literature review revealed that reproductive synchrony was common in colonial breeding damselfish species. Although these results suggest that within the breeding season, the timing and length of reproductive cycles cannot be explained by temperature alone, the observed changes in embryo size raise concern about the effects of changing oceanic conditions on this species.