Oculina Coral Banks 2003
Daily At-Sea Logs
May 6th, 2003

May 6, 03

Species Boundaries in Oculina corals

by Margaret Miller, NOAA-Fisheries

The coral species which constitutes the Oculina banks goes by the name Oculina varicosa (fig 1). Over the past few years, continued decline of the OHAPC O.varicosa population has been observed and virtually no new recruitment of new colonies has been observed on artificial restoration structures (fig 2), despite the stringent habitat protections that are in place. Due to these concerns, the National Marine Fisheries Service designated O.varicosa as a candidate for being listed as threatened or endangered under the federal Endangered Species Act.

Meanwhile, the taxonomy of the Oculina genus, traditionally based on external skeletal morphology, is unreliable and controversial. Thus, there is uncertainty as to whether the Oculina varicosa of the OHAPC is or is not a different species from the other Oculina species (or at least names) that range from North Carolina throughout the Caribbean (e.g. Oculina arbuscula, O.diffusa, O.robusta), and even in the Mediterranean (O. patagonica). In order to invoke the Endangered Species Act to afford additional protection to the Oculina Banks, such uncertainty regarding species identity of O.varicosa must be resolved. Working with a geneticist colleague at Louisiana State University, we will develop nuclear genetic markers to provide rigorous genetic determination of species boundaries in the Oculina genus.

The first step is to collect some small live samples (e.g. 5 cm branch tips, fig 3,the image is not a live specimen) from several colonies of O.varicosa which will be sent to LSU where the DNA will be extracted and used to develop the genetic markers. A “library” will be constructed of the nuclear DNA from these samples and this library will be used to choose markers (regions of the DNA) that have small amounts of variation between individuals from the same population but larger amounts of variation between different species. These markers will then be compared between the Oculina banks colonies and samples we will collect from other Oculina populations from other places to determine if they are the same or different species.

The collection of these initial samples was my objective for joining this cruise. Unfortunately, various problems with the ROV, including the breaking of the manipulator arm, make it uncertain if we will be able to collect live coral samples. In addition to the mechanical problems, the challenging current conditions in the area may also make the collections infeasible, as the ROV has only limited maneuverability and we do not want to cause damage to the overall coral structures. Hence, it remains to be seen if we will be able to collect live coral on this cruise to begin the genetic analysis.

Ph. 843-953-7263
Project Oceanica
Dept. of Geology & Environmental Geosciences
College of Charleston
Charleston, SC 29424
Fax 843-953-7850