A bio-oceanographic filter to larval dispersal in a reef-building coral

Abstract

Gene flow was shown to be limited between western and eastern Caribbean populations of the reef-building coral, Acropora palmata. However, some mixing was detected among populations near Puerto Rico. Our genetic analyses categorize A. palmata samples from the east coast of the Dominican Republic with the western Caribbean population, suggesting a filter to gene flow east of the Dominican Republic. To test the hypothesis of a present day bio-oceanographic filter occurring between Puerto Rico and the Dominican Republic (i.e., in the Mona Passage), we used a Lagrangian stochastic model (LSM) of larval dispersal, coupling coral life history characteristics with physical forcing. The model operated at two spatial scales: Caribbean-wide and focusing on the Mona Passage area. Results from the Caribbean-wide study showed no significant virtual larval exchange between the two populations. The small-scale model indicated that virtual larvae do not readily traverse the Mona Passage during the corals' reproductive season. Larvae released from Mona Island, in the center of the passage, are retained in the lee within topographically steered eddies, which act, together with the larval competency period, as a de facto filter to dispersal. Combined, our findings reveal the location of a seasonal filter to gene flow and its mechanism.

Coastal pollution limits pelagic larval dispersal

“…Most seascape genetic studies have focused on the role of oceanographic factors in determining genetic structure [23][24][25][26][27][28] . The SCB, however, is an oceanographically unique system with heterogeneous and variable mesoscale eddies influencing short-term circulation and the Southern California Cyclonic Gyre dominating longer term circulation patterns 29 .…”

The influence of oceanographic fronts and early-life-history traits on connectivity among littoral fish species

“…Significant progress has recently been made in our ability to accurately track pelagic stages (20)(21)(22), as well as in determining genetic connectivity patterns by combining oceanographic models and molecular genetic data (23)(24)(25). However, relatively few empirical studies have investigated how oceanographic conditions influence larval dispersal and ultimately gene flow among marine fishes with varying life-history strategies (7,26,27).…”

Planktonic larval mortality rates are lower than widely expected

“…Cowen et al (2000) demonstrated the importance of using accurate mortality rates in Lagrangian simulations of larval dispersal using ocean circulation models: higher mortality rates drastically decrease connectivity rates among habitat patches. Those model-derived connectivity probabilities are used to elucidate patterns of gene flow and vicariance (e.g., Baums et al 2006) and population and community dynamics (e.g., Berkley et al 2010, White et al 2010, and they are increasingly used to inform the design and analysis of marine protected areas (e.g., Rassweiler et al 2012, White et al 2013. To date, larval mortality remains a huge uncertainty in those models (Pineda et al 2009), and modelers typically rely on the original estimates of mortality from Rumrill (1990) for parameterization (Vaughn and Allen 2010).…”