Reproductive ecology of coral reef fishes: effect of fluctuating environments
Tomoyuki Kokita1) and Akinobu Nakazono2)
1) JSPS Postdoctoral Research Fellow, Kyushu University, Japan
2) Faculty of Fisheries, Department of Agriculture, Kyushu University, Japan
Many coral reef fishes inhabit tropical, subtropical and warm-temperate waters. Coral reef fishes have contributed to the development of fish ecology including behavioral ecology, population ecology and community ecology. For a long time, we have studied reproductive and social behavior of rocky and coral reef fishes at subtropical Okinawa Island and in warm-temperate Kagoshima, Japan. Recently, we consider that ecological traits of fishes inhabiting high latitudinal coral reefs may be an good example to discuss the response of coral reef fishes towards global-scale change of environments.
As is often the case in corals, many coral reef fishes show wide distribution because of planktonic life of early developmental stage. As a result of that, a single fish species inhabits environments with a broad-scale latitudinal gradient. Sea water temperature is one of the important gradient component. Seasonal change in environments of subtropical and warm-temperate waters is relatively large compared with tropical waters. Many species of coral reef fishes is likely to be essentially tropical species, suggesting that subtropical and warm-temperate fish assemblages emigrate from primary unfluctuating habitats to fluctuating habitats. Such environmental variation will result in phenotypic variation in some traits of fishes, especially reproductive traits being directly related to fitness of individuals, among the waters. Hence, comparison in reproductive traits of coral reef fishes between high and low latitude is important to know the response of coral reef fishes towards environmental change.
In this symposium, we compare reproductive traits of two coral reef fishes, Amphiprion clarkii (Pomacentridae) and Oxymonacanthus longirostris (Monacanthidae) between tropical waters and subtropical and warm-temperate waters, and describe that environmental pressures associated with high latitude environments modify the reproductive biology of essentially tropical reef fishes.
