Settlement and recruitment of three damselfish species: larval delivery and competition for shelter space

Abstract

Spatial patterns of settlement and abundance of older life stages were examined for three species of damselfish in the genus Dascyllus by monitoring natural colonization of standard amounts of initially empty juvenile microhabitat (anemones for D. trimaculatus; branching coral for D. flavicaudus and D. aruanus) transplanted to a series of sites within lagoons of Moorea, French Polynesia. Large spatial differences in larval colonization were observed, which were temporally consistent but different among the species. At the whole-island scale, D. trimaculatus settled primarily on the northern shore, while settlement of the other two species was greatest at the southern end. The three species also showed different patterns of settlement within lagoons: D. aruanus settled mainly nearer to shore, D. flavicaudus primarily on offshore lagoon portions and D. trimaculatus colonized equally across the lagoons. Among sites around the island, the relative abundance of older juveniles after 10 months was a curvilinear function of the relative abundance of settlers for two species (D. trimaculatus and D. flavicaudus). There was no relationship between patterns of settlement and abundance of older juveniles for D. aruanus, although juvenile abundance was inversely related to that of juvenile D. flavicaudus. At the within-lagoon scale, settlement mirrored almost exactly the relative abundance of older lifestages of D. trimaculatus and D. flavicaudus, whereas there was just a qualitative match for D. aruanus. A competition experiment revealed that juvenile D. flavicaudus had a greater effect on population growth of D. aruanus than vice versa, and this mechanism helped explain why the modification of settlement patterns was greatest in D. aruanus. Interspecific variation in abundance of older stages was shaped to differing extents by both patterns of larval delivery and subsequent density-dependent processes involving competition for shelter space.

A multi-scale study of the relationships between habitat use and the distribution and abundance patterns of three coral reef angelfishes (Pomacanthidae)

“…Depth distributions may also be maintained by preferential settlement of larvae to areas where adult conspecifics are already located (Sweatman 1983, Wellington 1992, but see Forrester 1995, 1999, Schmitt & Holbrook 1999. Or similarly, juvenile persistence may be confined to adult habitats, as has been found for cohabiting Stegastes congeners with complementary depth distributions (Wellington 1992).…”

Total volume of 3D small patch reefs reflected in aerial photographs can predict total species richness of coral reef damselfish assemblages on a shallow back reef

“…As such, the probability of a fish larva reaching a reef may not be proportional to reef area. Nonrandom recruitment of juveniles to a habitat patch has been reported for some coral reef fish species (Elliott et al 1995;Schmitt and Holbrook 1999;Hattori 2012). For example, residents chase newly settled juveniles of Dascyllus species out of the branching corals and sea anemones they inhabit when shelter space is insufficient (Schmitt and Holbrook 1999).…”

“…Nonrandom recruitment of juveniles to a habitat patch has been reported for some coral reef fish species (Elliott et al 1995;Schmitt and Holbrook 1999;Hattori 2012). For example, residents chase newly settled juveniles of Dascyllus species out of the branching corals and sea anemones they inhabit when shelter space is insufficient (Schmitt and Holbrook 1999). Furthermore, aggressive behavior in dominant fish keeps inferior competitors at the edges of the habitat patch where predation risk may be high (Holbrook and Schmitt 2002).…”

Changes in trophic community structure of shore fishes at an industrial site in the Gulf of Aqaba, Red Sea

“…Apart from trophic considerations, recruitment to the degraded reef could also be reduced, through decreased settlement due to habitat loss or through higher mortality due to loss of shelter space (Shulman 1985, Schmitt & Holbrook 1999.…”