Summary of Abstract Submission

Abstract Submission No. IO50-04-0014PresentationPoster

MODELING POTENTIAL CONNECTIVITY AMONG CORAL REEFS IN THE KENYAN-TANZANIAN REGION OF THE WESTERN INDIAN OCEAN

Harold (Hal) P. Batchelder*1, C.G. (Gaby) Mayorga Adame2

1 North Pacific Marine Science Organization (PICES), Canada
2 Oregon State University, USA

ABSTRACT :

Most coral reef organisms have bipartite life-cycles; they are site attached to the reefs as adults but have pelagic larval stages that allow dispersal to other reefs. Connectivity among discrete coral reef patches is critical to the survival of local populations of reef organisms. Predicting dispersal of planktonic larvae in the ocean is difficult, but crucial to the successful implementation of management strategies like Marine Protected Areas (MPAs). We use an individual-based particle tracking model (IBM) coupled to a 2km horizontal resolution ocean circulation model to examine connectivity among 661 coral reefs and 26 MPAs in the Kenyan-Tanzanian region. We assessed the impact of spawning seasonality, interannual variability of environmental conditions, pelagic larval duration and larval behavior on connectivity patterns. To illustrate the range of dispersal and connectivity patterns likely to occur among the great variety of reef organisms we simulate virtual larvae of two ecologically important reef groups with different pelagic larval durations and behaviors: Acropora corals and Acanthurid surgeonfish. The East African Coastal Current has an overall south to north dispersal pattern. The mean percentage of virtual larvae successfully reaching suitable habitat is 24% for Acanthurids and less than 0.3% for Acroporids. Coastal morphology and ocean circulation interact to create local hot-spots of larval retention. The connectivity matrices describe potential recruitment pathways among the individual reefs, and provide guidance for the implementation of a more efficient network of MPAs.