The
Caribbean
reef shark, Carcharhinus perezi is an important, but
poorly understood apex predator important in shaping the ecology
of coral reef ecosystems throughout the Caribbean, Gulf of
Mexico and east coast of South America. The goals of this
project were to characterize the nursery areas used by Caribbean
reef sharks at a location where they are common and where the
presence of marine protected areas (MPAs) may help to sustain
their local populations. Standardized
fishing surveys were conducted from 1999 to 2003 to describe the
spatial distribution, nursery habitat and the time of
parturition of Caribbean reef sharks at Fernando de Noronha.
The capture of 143 individuals (71-224 cm) indicated that the
insular shelf (from 5-30 m depth) is used as nursery area by
this species and that parturition occurs from December to April,
with a peak in February-March. These sharks were uncommon
outside the marine protected area. Additionally, we examined the
movement patterns and long term site-fidelity of Caribbean reef
sharks using tag-recapture and automated telemetry at Fernando
de Noronha. Twenty-two of 143 (15.3%) externally
tagged juvenile sharks (<110cm) were recaptured between 0-5
km from the site of tagging after 5-800 days at liberty,
suggesting some site fidelity in young individuals of this
species. Site-fidelity and movement patterns of ten juvenile
sharks ranging from 78 to 110 cm, and one adult female (224 cm),
were also investigated for periods of up to two years with an
array of automated telemetry receivers. Catch-per-unit effort and telemetry data from inside and outside a marine
protected area (MPA) both show that shark abundance and activity
is greatest along the part of the archipelago’s coastline
least disturbed by human activity. Juvenile sharks
demonstrated a high degree of site-fidelity and occupied
specific locations along the coast throughout the year, with
some evidence of increased activity space with ontogeny. Sharks
appeared to range more widely at night and there were no
seasonal variations in habitat use. Our results suggest that marine protected areas may be a useful conservation
tool to protect young Caribbean reef sharks and potentially
other reef-dwelling carcharhinid sharks during their early
life-history.
For
pdf versions of publications resulting from our study click on
the manuscript below.
Garla,
R.C., D.D. Chapman, M. Shivji, B.M. Wetherbee & A.F. Amorim.
2006. Habitat of juvenile
Caribbean
reef sharks, Carcharhinus perezi, at two oceanic insular
marine protected areas in the
southwestern Atlantic Ocean
:
Fernando de Noronha
Archipelago and Atol das Rocas,
Brazil
. Fish Res. 81:236-241.
Garla,
R.C., D.D. Chapman, B.M. Wetherbee, M., Shivji. 2006. Movement
patterns of young
Caribbean
reef sharks, Carcharhinus perezi, at
Fernando de Noronha
Archipelago,
Brazil
: the potential of marine protected areas for conservation of a
nursery ground. Mar. Bio.
149(2):189-199.