IPhD ThesisParrotfishes contribute to more than 80% of the biomass of herbivorous fishes
in the Caribbean and they have been the dominant grazers on reefs since 1983.
Maintaining healthy parrotfish populations is essential to help conserve benthic habitat
cover which is suitable for the settlement and growth of reef building corals. However,
the key environmental factors that currently affect local parrotfish abundance and
population structure are scarcely known. Many reef studies are constrained to a limited
geographical scale which may not be applicable at larger spatial scales. Parrotfish data
across the wider Caribbean will help to overcome such issues.
This study investigates three relationships including parrotfish density and
benthic habitat variables (Chapter 2); parrotfish density and fishing pressure (fisher
density, human population, MPA protection) (Chapter 3); and parrotfish size at sex
change and fishing pressure (Chapter 4). Fish and benthic habitat surveys at 7 to 15
sites were conducted in each of eight Caribbean countries including Antigua, Bonaire,
Barbados, Curaçao, Dominican Republic, Jamaica, St. Lucia, and St. Vincent and the
Grenadines.
Parrotfish abundance was positively correlated with coral cover and negatively
correlated with macroalgal cover. Parrotfish abundance had a significant correlation
with reef complexity (Chapter 2). Different sizes of parrotfish were associated with
different habitats (Chapter 2). Fishing is likely to have reduced fish numerical
abundance and biomass even at Caribbean scale (Chapter 3). While parrotfish
biomass was significantly higher within MPAs, parrotfish numerical density was not
significantly different (Chapter 3). The density of terminal parrotfish was significantly
different (Chapter 4). Furthermore, fishing pressure was significantly correlated with
the size at which phase change between initial and terminal phases occurs (Chapter
4).
This research demonstrates the major drivers of Caribbean parrotfish
abundance and biomass which may help inform management of parrotfish and
promote further coral reef ecosystem recovery.The Indonesian Government’s Directorate General of
Research and Higher Education Resources, Ministry for Research and Higher
Education (formerly Ministry for Education and Culture)
