11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 10: Ecological Processes on Today's Reef Ecosystems
10.325
Within And Among-Site Variability in Early Post-Settlement Survivorship Of A
Brooding Coral
Megan PORTER* 1 , Wade COOPER 1
1 Division of Marine Biology and Fisheries, RSMAS, University of Miami, Miami, FL
Surviving the first few days to weeks after settlement is a difficult yet crucial stage for
many marine invertebrates, including corals. Despite the importance of this stage for
recruitment dynamics, information on early post-settlement survivorship rates, and the
processes controlling these rates, remains limited due to logistical difficulties in studying
these cryptic and microscopic stages in situ. To address these deficiencies, the goals of
this study were to quantify the early post-settlement survivorship of the brooding coral
Porites astreoides, and to assess variability in these rates both within and among four
patch reef locations. To accomplish this, larvae were settled onto small substrate chips in
the laboratory, transplanted to the reef within four to six days after settlement, and
monitored in situ using fluorescent techniques, both in 2006 and 2007. Overall,
survivorship among the four sites in both years ranged from 1% to 25% surviving the
first month after settlement. Survivorship was slightly lower in 2006 than 2007, and was
significantly different among sites in 2007 but not 2006, although the rankings of sites
were similar. In both years, survivorship was highly variable within a site, suggesting
spatial patchiness in the mechanisms leading to mortality. Although this study did not
address specific mechanisms of mortality, quantification of these early survivorship
patterns is a useful first step towards proposing more detailed hypotheses on the
processes which structure recruitment dynamics.
10.326
Differences in Coral Reef Fish Assemblages Between Mangrove-Poor And
Mangrove-Rich Islands
Jessica HARM* 1 , Martin SPEIGHT 1
1 Zoology, University of Oxford, Oxford, United Kingdom
Visual surveys of coral reef fish were conducted on two islands (and associated cays) off
the Caribbean coast of Honduras, Cayos Cochinos (mangrove poor) and Utila (mangrove
rich). Local populations on both islands exploit reefs, seagrass, and mangroves, and Utila
suffers from higher fishing pressure compared to Cayos Cochinos, the latter having a
conservation plan and no-take zones. Cayos Cochinos houses only one small mangrove
stand (length= 246m), while Utila houses two large mangrove lagoons and fringing
mangroves on its north side (total length >1400m). A total of 108 species (excluding
cryptic species, gobies/blennies) were found during the survey. Species richness was
higher on Utilian coral reefs. Eight randomly laid out 50m transects were surveyed at
each site (six sites per island). There was a significant difference (p