Abstract: The geographic partition of genetic variation, also known as population structure, is an essential attribute of a species’ biology and a useful tool for resource managers to make informed decisions for the protection and long-term preservation of the species. Among the most severe deteriorations of coral reefs have been recorded in the Caribbean Sea and such biological knowledge from key species could assist stakeholders to construct sound management plans. The population structure of the iconic Caribbean Sea fan, Gorgonia ventalina Linnaeus, 1758, was estimated from DNA sequences of the mitochondrial marker MutS Like Homolog protein 1 (MSH1) and the nuclear marker Signal Recognition Particle 54 intron (SRP54). Samples encompassed most of the species’ known distribution from Curaçao to Florida, the Lesser Antilles to Panamá, and Bermuda. Analysis of molecular variance revealed a significant amount of population differentiation between the eastern and western Caribbean with the MSH1 gene, however, no such signal was detected with the SRP54 intron. The Old Buoy and Mario reefs of western and southwestern Puerto Rico were the most genetically differentiated among all sites based on the MSH1 gene. Local current patterns at the reef level and low sample sizes are possible explanations for the observed patterns of genetic differentiation. Comparisons with other studies using microsatellites and SNPs, including a study with G. ventalina suggests that faster-evolving genomic areas are more appropriate markers for the detection of fine-scale population differentiation in G. ventalina.
Background: The hydrocoral Millepora is an important framework builder that dominates shallow turbulent environments in the Indo-Pacific and the Atlantic-Caribbean. The Caribbean representatives of the genus are classified in four species - Millepora alcicornis, Millepora complanata, Millepora striata, and Millepora squarrosa - but their taxonomic boundaries are not clearly defined. We used mitochondrial gene sequences to delineate the four Millepora species and evaluated whether morphological traits and mitochondrial sequence divergence were correlated for two most common species M. alcicornis and M. complanata.
Results: Samples were collected from Puerto Rico, Guadeloupe, Curaçao, Grand Cayman, and Panama during 2006 to 2007. Diameter of dactylopores distinguished the branching and encrusting morphotypes of M. alcicornis and M. complanata, and gastropore diameter discriminated between M. alcicornis and M. complanata. High levels of haplotypic diversity (Hd = 0.94) were observed, with the most common haplotypes shared by M. alcicornis and M. complanata. Sequence divergence ranged from 0% to 3% among M. alcicornis, M. complanata, and M. striata to 25% between these three species and M. squarrosa. Bayesian analysis of cytochrome oxidase subunit I (COI) gene indicated the presence of three Caribbean taxa: M. squarrosa, M. striata, and the ‘species complex’ encompassing the morphologies displayed by M. complanata and M. alcicornis.
Conclusions: The branched M. alcicornis and encrusted M. alcicornis and M. complanata can be differentiated morphologically but not genetically. Phylogenetic analysis suggests that the Caribbean milleporids include three species - M. squarrosa, M. striata, and the species complex of M. alcicornis-M. complanata. Millepora striata is closely related to the M. alcicornis-M. complanata species complex.
Many fishes, including groupers, produce sounds associated with mating behavior; recording and analyzing the occurrence of these sounds can provide long time-series records of grouper use of spawning habitat. Red hind Epinephelus guttatus sound production was recorded on spawning aggregation sites off the west coast of Puerto Rico and at Mona Island, Puerto Rico. Audio- video recordings were used to identify a species-specific sound produced by male red hind, most commonly during territorial patrols, and also during interactions with females. This sound is low in frequency (50 to 400 Hz) and consists of a series of pulses repeated at a variable rate. Long-term acoustic recorders were placed off the west coast of Puerto Rico at Abrir La Sierra and at Mona Island to record the timing of red hind sound production from January through March. Red hind sounds were detected at all times of the day, with peaks in sound production just before dusk. Monthly peaks in sound production were evident in each time series, but the monthly peak in sound production at Abrir La Sierra was 6 d later than the peak at Mona Island, suggesting that the timing of spawning of these 2 aggregations, while on a lunar schedule, was not broadly synchronized during this time period. This research lays the groundwork for both long-term monitoring and mapping of red hind spawning sites that will be useful for managing spawning aggregations, especially in remote areas.