Publication Date

2019-12-09

Availability

Open access

Embargo Period

2019-12-09

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Marine Ecosystems and Society (Marine)

Date of Defense

2019-10-25

First Committee Member

Maria Estevanez

Second Committee Member

Evan D'Alessandro

Third Committee Member

Rafael J. Araújo

Fourth Committee Member

Heather Stewart

Abstract

Coral reefs and mangroves play a variety of roles in the lives of reef fishes, serving as nursery, feeding, and breeding grounds. Mangroves, while often near reef ecosystems, do not typically have suitable conditions for coral recruitment and growth, though mangrove-coral habitats do occur. The distribution and extent of these mangrove-coral habitats, as well as the composition of the fish community that utilizes them, are poorly understood. In several locations throughout Bocas del Toro, Panama, many species of corals grow on and among submerged red mangrove (Rhizophora mangle) prop roots. This study aimed to analyze the reef fish community in a mangrove-coral habitat, quantifying the effect coral presence has on the red mangrove fish community. I conducted visual underwater fish surveys in coral and noncoral mangrove habitats throughout Bocas del Toro. Furthermore, I conducted an experiment in which I placed artificial coral among the mangrove prop roots to differentiate the effect of live coral vs. hard substrate on the mangrove fish community. Of the 28 fish species (encompassing 11 families and 4 trophic groups) observed, over 90% were juveniles, and 57% occurred at both coral and noncoral mangrove habitats. Noncoral sites had higher abundances of Sphyraena barracuda and invertebrate feeders. Coral sites had greater species richness and higher abundances of roving herbivores (Scarus spp.) and territorial herbivores (Stegastes spp.). In an experimental component of the research, the addition of the artificial coral increased total fish abundance (particularly roving herbivores), indicating that roving herbivores are attracted to the hard substrate that corals provide. The addition of the artificial coral did not affect the abundance of territorial herbivores, indicating that these fishes may require more time to recruit or that they rely on biological cues from living coral. The mangrove-coral habitat in Bocas del Toro is functioning primarily as juvenile habitat for reef fishes, with more species (particularly Scarus spp. and Stegastes spp.) attracted to the mangrove-coral habitat compared to other mangrove fringe communities. The presence of coral has made the habitat more favorable for species who tend to prefer coral reef habitats, while the mangrove prop roots provide necessary shelter from predators and additional food resources for fishes. Specific effort should be spent conserving mangrove-coral habitats, as this habitat type is unique, seldom found, and provides the ability to conserve mangroves, corals, and reef fishes all within one location.

Keywords

mangroves; corals; fish communities; reef fish; Bocas del Toro; mangrove-coral habitat

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