Population Regulation of Coral Reef Fishes

Populations of reef fish are widely believed to be limited by availability of larval recruits, not by density dependent processes operating during and after settlement of young stages in the reef environment.Our research explores and challenges this thinking.  We are utilizing field observations and experiments to determine what factors affect spatial distribution, abundance, and population dynamics of four reef-dwelling damselfish in the Family Pomacentridae: three-spot humbug (Dascyllus trimaculatus), yellow-tail humbug (D. flavicaudus), banded humbug (D. aruanus), and orange-fin anemonefish (Amphiprion chrysopterus).  In related research, we explore the relationships between structural reef habitat (types and sizes of corals and other reef substrates) and the abundance and diversity of local assemblages of lagoon fish, and whether depleted populations of reef fish can be restored by attraction of larval stages to reef environments using lights at night.  More recently, we have begun to examine in detail the species interactions that occur among species of fish that co-occur on anemones, corals and on patch reefs, their interactions with co-occurring invertebrates (such as crabs), and the costs and benefits to the anemones and corals of hosting various species.
Knowledge of factors that regulate populations of marine fish is essential to a general understanding of the ecology of coral reef ecosystems.  This knowledge is invaluable for management and conservation of fish populations, and can aid in these practices.  Species of Pomacentrids are very typical and abundant coral reef fish; we anticipate that our findings will have general applicability, including to species of fish that are consumed by humans.  Our research on the relationshipes between fishes and the corals they inhabit will reveal techniques that could aid in restoration of degraded reef areas.  This work is also providing important data about the factors that affect distribution and abundance of lagoon fish, as well as the temporal and spatial scales over which these assemblages vary.  Such information is important for planning of fishing practices and in other types of natural resource management (for example, establishment of marine protected areas).  In addition, we are exploring various methods of restoration of depleted populations of reef fish, including the use of light to attract settlement stages of fish to the reefs.This technology could allow redirection of larval fish that would otherwise be lost from the system to reef areas that are in need of restoration.
Report (English, French)

Project Information
Holbrook&Schmitt_2005_en.pdf27.81 KB
Schmitt & Holbrook, Final Report 2007.pdf40.58 KB
Schmitt & Holbrook, Final Report 2006.pdf40.36 KB
Schmitt & Holbrook, Rapport 2006_fr.pdf43.24 KB