Colony morphology,age structure,and relative growth of two gorgonian corals,Leptogorgia hebes (Verrill) and Leptogorgia virgulata (Lamarck), from the northerm Gulf of Mexico

Along the northeastern Gulf of Mexico coast, Leptogorgia hebes is the predominant gorgonian at two inner shelf (22 and 27 m) sites, while Leptogorgia virgulata dominates a third shallow (1–2m), inshore site. The axial skeleton of both species is composed of concentric rings which appeared to exhibit annual periodicity. Although age structure of the populations differed between shelf sites, neither colony growth rates, estimated from direct measurements of ring widths plotted on Walford graphs, nor overall branching complexity, determined from bifurcation ratios (R_b), differed between the shelf populations. Larger individuals at the 27m shelf site were simply older than those at the shallower (22m) shelf site. Walford plots of growth increments revealed colony growth of the shallow inshore species to be similar to that of the offshore species.