Food availability affects growth in a coral reef fish

Area of Science:

• Marine Ecology
• Coral Reef Fish Ecology

Background:

• Pomacentrus amboinensis juveniles exhibit preferential settlement on deeper reefs in One Tree Lagoon.
• Preliminary studies suggest better growth and survivorship in deeper waters.

Purpose of the Study:

• To test the hypothesis that food availability drives differential growth and survivorship between shallow and deep reef habitats for P. amboinensis.
• To assess the impact of food supplementation on juvenile fish growth rates across different depth strata.

Main Methods:

• A supplemental feeding experiment was conducted over one month on P. amboinensis juveniles at two depth strata.
• Juveniles were fed daily, with growth rates compared between supplemented and control reefs.
• No mortality was observed during the experimental period.

Main Results:

• Food supplementation markedly increased juvenile fish growth rates across all tested reefs.
• Growth rates differed between depth strata, but food supplementation effects did not interact with depth.
• Food availability appears to be a limiting factor for growth in both shallow and deep reef habitats.

Conclusions:

• Food is a limiting resource for P. amboinensis growth in both marginal shallow and preferred deeper reef environments.
• While depth influences growth, food availability is a critical factor impacting juvenile fish performance in coral reef ecosystems.