11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 10: Ecological Processes on Today's Reef Ecosystems
10-57
A Comparison Of Rates And Structure Of Social Foraging Interactions in Coral
Reef Fishes
Kimberly BARBER 1 , Peter AUSTER* 1
1 University of Connecticut, Groton, CT
We compared the rates and structure of social foraging groups at reef sites in the Gulf of
California, off Bonaire in the Caribbean Sea, and on the Great Barrier Reef. Data were
collected on number and composition of social foraging groups and background
community composition. While on a regional scale species richness varied (i.e., Coral
Sea > Caribbean > Gulf of California), comparisons of local community diversity and
diversity of species participating in social foraging groups were not statistically different.
Approximately 50% of species in local communities participated in social foraging.
Sixteen to 30% of species participated in single species groups while 31%-46% of
species participated in mixed species groups. Most groups, whether single or mixedspecies,
were composed of 2-9 individuals. Rates of social foraging varied with a mean
of approximately 7 bouts per survey at Gulf of California and Caribbean sites, while only
4 bouts per survey were observed at Coral Sea sites. Interaction strengths between social
foragers were “mapped” using cluster analysis and similarity levels were indicative of the
consistency of such interactions. Mixed-species foraging groups observed at Gulf of
California and Caribbean sites had highly mixed trophic guild composition while those at
Coral Sea sites were composed primarily of species within single trophic guilds. Our
results demonstrate the extent of social foraging interactions across a wide geographic
range and infer a level of importance yet to be defined for the role such positive species
interactions play in mediating local community structure and diversity.
10-58
Short-term effects of the invasive Indo-Pacific lionfish (Pterois volitans/miles
complex) on Bahamian coral-reef fish abundance and diversity
Mark A. ALBINS* 1
1 Department of Zoology, Oregon State University, Corvallis, OR
Caribbean coral-reef communities have been substantially degraded over the last several
centuries by numerous natural and anthropogenic disturbances. These communities now
face a new threat: the invasive Indo-Pacific lionfish. Lionfish are voracious predators
with defensive venomous spines. Using oversized, ornate pectoral fins, they herd and
ambush small reef fishes and crustaceans, a novel strategy in the invaded system. Since
2005, we have observed increasing densities of lionfish at multiple study sites within
Exuma Sound, Bahamas. During the summer of 2007, we initiated a combination of
observational and experimental investigations to determine the effects of this invasive
predator on native coral-reef fish communities. We observed a high rate of lionfish
recruitment (ca.16 fish ha-1day-1) to a matrix of artificial (concrete-block) and
translocated (live-coral) patch reefs over the summer recruitment period. Stomachcontent
analysis in combination with aquarium feeding observations confirmed that
lionfish prey on a wide variety of native animals, including bony fishes and crustaceans,
and that lionfish are capable of consuming large numbers of prey, as well as large prey
relative to their body size. We ran a controlled experiment (lionfish present vs. absent)
using a matrix of artificial and translocated patch reefs to examine the effects of lionfish
on the survival of small reef-fishes. Reefs were censused at one-week intervals for a
period of five weeks during the height of the summer recruitment season. Although
lionfish affected the abundance of species differentially, the mean abundance and species
diversity of small reef-fishes (