GOFFREDO, S.; LASKER, H.R.*; University of Bologna; University at Buffalo: Modular Growth of a Gorgonian Coral Generates Predictable Patterns of Colony And Population Growth

The modular construction of colonial organisms can generate complex growth patterns that incorporate both growth and partial mortality. While that patterning can confound simple descriptions of growth it is not a necessary outcome of modularity. In some cases, modularity can generate predictable patterns of colony growth that are amenable to modeling approaches more commonly used in unitary organisms. Colonies of the Caribbean gorgonian Pseudopterogorgia elisabethae from a 20 m deep population in the Bahamas exhibit such characteristics. Mass was highly predictable from colony height, following a power function with an exponent of 2.1 (r2 = 0.94). Height and mass were also closely related to age, determined both on the basis of counts of annual growth rings and extrapolations of colony growth rates from other Bahamian populations. Based on those data and observations of spawning, colonies reach sexual maturity at 5-7 y and can live to 35-38 y. As growth declines with increasing size/age maximum colony biomass accumulation occurs at 15-18 y (41-43 cm height). Size/age distributions were used to estimate survivorship which when applied to a von Bertalanffy population model suggest a maximum yield at 10-12 y (31-32cm). P. elisabethae is harvested in the Bahamas by cropping colonies. Although not a model of the cropping process, the data suggest that allowing colonies to grow to more than 30 cm can maximize yields.