Abstract
Elevated sea surface temperatures associated with El Niño-Southern Oscillation (ENSO) can severely impact coral populations in the Galápagos Islands, Ecuador. During the 1982-83 event, 95-99% of reefbuilding corals bleached and died. This study examines if the onset of the 2015-2016 ENSO affected the important reef-building coral Pocillopora damicornis. The largest known population of this species in the Islands is found in the Concha de Perla lagoon on Isabela Island. It was first surveyed in 2012 and was visited again in 2015 to determine if colony size and coral condition (bleaching, paling, or mortality) changed. Underwater photographs were quantified for these attributes using the Coral Point Count with Excel Extensions (CPCe) program. In 2012 1,617 colonies were surveyed compared to 370 in 2015. There was a significant increase in live mean colony size from 2012 (249.8 ± 305.3) to 2015 (327.8 ± 257.4), (p < 0.001, t-Test), suggesting that corals continue to grow. Live colony sizes were skewed right in both surveys, typical of coral population structure for most species. However, the mode shifted from the smallest size classes in 2012 to slightly larger size classes in 2015. This indicates that colonies grew in size, but there was a reduction in new recruits, suggesting a decline in successful reproduction. Coral bleaching and paling were not observed. Because this population is monoclonal with no genetic variability, it is more susceptible to the types of environmental change associated with ENSO and continued monitoring of this persistent population is warranted until regional conditions normalize.
Faculty Sponsors
Dr. Joshua Feingold
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-8-2016 1:00 PM
End Date
4-8-2016 5:30 PM
Changes in Coral (Pocillopora damicornis) Population Structure in Concha de Perla Lagoon, Isabela Island, Galápagos Islands, Ecuador
Alvin Sherman Library
Elevated sea surface temperatures associated with El Niño-Southern Oscillation (ENSO) can severely impact coral populations in the Galápagos Islands, Ecuador. During the 1982-83 event, 95-99% of reefbuilding corals bleached and died. This study examines if the onset of the 2015-2016 ENSO affected the important reef-building coral Pocillopora damicornis. The largest known population of this species in the Islands is found in the Concha de Perla lagoon on Isabela Island. It was first surveyed in 2012 and was visited again in 2015 to determine if colony size and coral condition (bleaching, paling, or mortality) changed. Underwater photographs were quantified for these attributes using the Coral Point Count with Excel Extensions (CPCe) program. In 2012 1,617 colonies were surveyed compared to 370 in 2015. There was a significant increase in live mean colony size from 2012 (249.8 ± 305.3) to 2015 (327.8 ± 257.4), (p < 0.001, t-Test), suggesting that corals continue to grow. Live colony sizes were skewed right in both surveys, typical of coral population structure for most species. However, the mode shifted from the smallest size classes in 2012 to slightly larger size classes in 2015. This indicates that colonies grew in size, but there was a reduction in new recruits, suggesting a decline in successful reproduction. Coral bleaching and paling were not observed. Because this population is monoclonal with no genetic variability, it is more susceptible to the types of environmental change associated with ENSO and continued monitoring of this persistent population is warranted until regional conditions normalize.
