Uniform TitleVariation among mangrove forests as fish habitat: the role of prop-root epibionts, edge effects and behavior in neotropical mangroves
NameMacDonald, James A. (author), Weis, Judith (chair), Jordan, Rebecca (internal member), Morin, Peter (internal member), Rachlin, Joseph (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectEcology and Evolution,
DescriptionMangrove forests are an important nursery habitat for many species of reef fish, as well as a key component of the interlinked mangrove-seagrass-reef system. However, understanding how juvenile fish utilize the mangrove habitats is hampered by variation between mangrove habitats. This study sought to examine some reasons for variation between mangroves, focusing on physical characteristics, particularly the influence of sessile epibiont organisms.
Using visual census, fish and sessile communities were compared in Rhizophora mangle roots in Bocas Del Toro, Panama, and Utila, Honduras. The results revealed significant positive correlation between depth, epibiont diversity, and density and fish species diversity and biomass.
In order to determine a causal relationship between epibionts and fish community variation, two field experiments were established. In one, artificial mangrove roots (AMR) with different sets of artificial (AE) or real epibionts were established in five different locations. In the second experiment, fish were surveyed in 12 different mangrove transects, epibionts were reduced in half of those transects, and then surveyed again. In the artificial mangrove plots, treatments with the most heterogeneous structure had the greatest abundance and diversity of fish. When epibionts were reduced, fish abundance went up and biomass stayed level in controls, but abundance stayed flat and biomass decreased in treatment transects. The data indicate that epibionts can enhance fish abundance and diversity in mangroves, although the relationship may depend upon the specific epibionts.
Separately, a series of prop-roots were surveyed and placed inside predator exclusion cages. After three months, the cages were removed. The results suggested that grazing mostly does not impact prop-root epibiont coverage.
In a separate study, fish and epibiont communities were measured along a gradient within the mangroves away from boundaries of the mangrove forest. Both fish diversity and abundance showed a significant linear decrease away from the edge. Average size decreased as well, but epibionts showed no significant changes along the gradient.
Last, juvenile reef fishes were captured by in mangroves and seagrass, tagged, and monitored for three months. All recaptures were within 10 meters of the original capture, but most occurred within a short time.
NoteIncludes bibliographical references (p. 138-149).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.