Abstract
Porites sverdrupi is a rare, endemic free living coral that only inhabits the Mexican Eastern Tropical Pacific at depths typically between 20 and 40 meters. Until recently it was considered an ecomorph of the more abundant congener Porites panamensis, so there are few studies focused solely upon this species. The volatility of the populations of corals in this region and a continually decreasing habitat has led some researchers to conclude that P. sverdrupi may be undergoing a natural process of extinction. This study initiates a multi-year analysis of the population trend of P. sverdrupi off the coast of Isla Catalana in Baja California. Forty randomly positioned ½ x ½ m photo quadrats were obtained in an area with an exceptionally dense population of this species. Images were analyzed using the CPCe program, revealing that P. sverdrupi had an average surgace area of 2.44 cm2, with about 55 colonies per square meter and an average live coral tissue cover of 1.35%. This compares with other studies that report population densities and live tissue cover over one order of magnitude lower. This suggests that microhabitat refuges, such as the one at Isla Santa Catalina, allow hope for the continued survival of Porites sverdrupi. This important baseline study on one population of this species will be followed by biennial surveys to determine long-term trends. It will then be possible to identify if more aggressive conservation efforts will be needed to prevent the extinction of this locally important species.
Faculty Sponsors
Dr. Joshua Feingold
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-13-2012 1:00 PM
End Date
4-13-2012 5:30 PM
Population Densities of Porites sverdrupi, a Coral Limited to the Mexican Eastern Tropical Pacific
Alvin Sherman Library
Porites sverdrupi is a rare, endemic free living coral that only inhabits the Mexican Eastern Tropical Pacific at depths typically between 20 and 40 meters. Until recently it was considered an ecomorph of the more abundant congener Porites panamensis, so there are few studies focused solely upon this species. The volatility of the populations of corals in this region and a continually decreasing habitat has led some researchers to conclude that P. sverdrupi may be undergoing a natural process of extinction. This study initiates a multi-year analysis of the population trend of P. sverdrupi off the coast of Isla Catalana in Baja California. Forty randomly positioned ½ x ½ m photo quadrats were obtained in an area with an exceptionally dense population of this species. Images were analyzed using the CPCe program, revealing that P. sverdrupi had an average surgace area of 2.44 cm2, with about 55 colonies per square meter and an average live coral tissue cover of 1.35%. This compares with other studies that report population densities and live tissue cover over one order of magnitude lower. This suggests that microhabitat refuges, such as the one at Isla Santa Catalina, allow hope for the continued survival of Porites sverdrupi. This important baseline study on one population of this species will be followed by biennial surveys to determine long-term trends. It will then be possible to identify if more aggressive conservation efforts will be needed to prevent the extinction of this locally important species.
