Otolith growth of Springer's demoiselle, Chrysiptera springeri (Pomacentridae, Allen & Lubbock), on a protected and non-protected coral reef

The structural complexity of coral reefs is important for their function as shelter and feeding habitats for coral reef fishes, but physical disturbance by human activities often reduce complexity of the reefs by selectively destroying fragile and more complex coral species. The damselfish Springer's demoiselle Chrysiptera springeri primarily utilize complex coral heads for shelter and are hence vulnerable to human disturbance. In order to evaluate the potential effect of habitat degradation on juvenile fish growth, coral reef cover, fish age at settling and otolith growth, juvenile Springer's demoiselle was investigated on a protected and non‐protected coral reef in Darvel Bay, Borneo. The protected reef had higher coverage of complex branching corals and exhibited a more complex 3‐dimensional structure than the non‐protected reef. Springer's demoiselle settled at the same age on non‐protected and protected reefs. The growth rates of the otoliths from Springer's demoiselle were similar during the pre‐settlement period on the two reefs (manova , P > 0.05), but from age 20 to 48 days (post‐settlement period) the otolith growth rate of juveniles on the non‐protected reef was reduced compared to those from the protected reef (manova , P = 0.017). However, the differences in the otolith size, and by inference, fish size, after 48 days were small. The small effect of habitat degradation on growth is likely related to the fact that the Springer's demoiselles collected on the non‐protected reef were associated with the few remaining complex coral heads. Increased foraging‐predation tradeoffs on the non‐protected reef may decrease food intake and growth of juvenile Springer's demoiselle, but the main effect of habitat degradation on their abundance is likely to be related to lack of suitable shelter, and consequently reduced carrying capacity, on disturbed reefs.