Abstract
At Isla Catalana in the SW Gulf of California, Mexico an endemic coral species Porites sverdrupi lives unattached within rhodolith beds. Very little biological and ecological information is known about this species. Where previously described, Porites sverdrupi was found as widely scattered colonies in very low densities (0.0038%). Random walk quadrat sampling was done with a primarily monospecific aggregation of P. sverdrupi. Twenty five (½m x ½m) photo quadrats obtained in August 2014 were analyzed using CPCe software and compared to values in 40 quadrats from 2011. The number of colonies per square meter significantly increased from 54.7 in 2011 to 74.6 in 2014 (T-test, p<<<0.001). Average colony size increased significantly over this period from 2.47 cm2 to 6.61 cm2 (T-test, p<<<0.001). There was a significant increase in coral cover from 1.35% in 2011 to 5.39% in 2025 (T-test, p<<<0.001); a 399% increase over a 3 year period. Thus, increased coral cover was due to both population growth and increased coral size. Early studies had led researchers to believe Porites sverdrupi was undergoing a natural extinction process. However, this research documents a vibrant and growing coral community, heartneing news during a time of coral cover loss in most other locales. This community is of ecological value due to its carbonate production that increases structural heterogeneity, providing habitat for a wide variety of associated organisms. This study further clarifies the need for conservation efforts in this unique location.
Faculty Sponsors
Joshua Feingold, Ph.D.
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-10-2015 1:00 PM
End Date
4-10-2015 5:30 PM
Changes in Population Densities of Porties sverdrupi, an Endemic Coral of the SW Gulf of California
Alvin Sherman Library
At Isla Catalana in the SW Gulf of California, Mexico an endemic coral species Porites sverdrupi lives unattached within rhodolith beds. Very little biological and ecological information is known about this species. Where previously described, Porites sverdrupi was found as widely scattered colonies in very low densities (0.0038%). Random walk quadrat sampling was done with a primarily monospecific aggregation of P. sverdrupi. Twenty five (½m x ½m) photo quadrats obtained in August 2014 were analyzed using CPCe software and compared to values in 40 quadrats from 2011. The number of colonies per square meter significantly increased from 54.7 in 2011 to 74.6 in 2014 (T-test, p<<<0.001). Average colony size increased significantly over this period from 2.47 cm2 to 6.61 cm2 (T-test, p<<<0.001). There was a significant increase in coral cover from 1.35% in 2011 to 5.39% in 2025 (T-test, p<<<0.001); a 399% increase over a 3 year period. Thus, increased coral cover was due to both population growth and increased coral size. Early studies had led researchers to believe Porites sverdrupi was undergoing a natural extinction process. However, this research documents a vibrant and growing coral community, heartneing news during a time of coral cover loss in most other locales. This community is of ecological value due to its carbonate production that increases structural heterogeneity, providing habitat for a wide variety of associated organisms. This study further clarifies the need for conservation efforts in this unique location.
