SS1.02 Geochemical Tracers in Calcified Structures: Implications for Fisheries Research
Date: Tuesday, June 11, 2002
Time: 2:15:00 PM
Location: Carson A
DiBaccoC, Woods Hole Oceanographic Institution, Woods Hole, USA,
Thorrold, S, , Woods Hole Oceanographic Institution, Woods Hole, USA, 
Estimating Larval Connectivity in Mussel (Mytilidae) Populations using Geochemical Signatures in Shell Aragonite.
The early life history of most marine benthic invertebrates involves the release of eggs and larvae that are spend considerable amounts of time (weeks to months) in the plankton before settling into adult habitats. This dispersive stage acts to maintain the exchange of genetic information among populations that may otherwise be reproductively isolated. However, there remains considerable debate as to how far, and how frequently, larvae disperse from their natal locations. Utility of elemental and isotopic differences in shell aragonite as viable tags to identify source populations of blue mussel larvae has recently been initiated. Short term objectives (next 6-8 months) include; 1) Developing inductively coupled plasma mass spectrometric techniques to analyze juvenile mussel shells, and 2) characterization of site-specific geochemical signatures for Mytilid shells sampled from estuarine and coastal habitats along Massachusetts (Mytilus edulis) and Baja California, Mexico (Mytilus californianus) coasts. The development of viable tags will allow us to 3) determine the relative contribution of larvae from local and remote sources to mussel populations at bay and coastal sites, and 4) compare larval dispersal pathways with coastal circulation patterns to determine if variability in connectivity rates among study locations can be explained by physical oceanographic processes acting over relevant spatio-temporal scales. Anticipated long term objectives of this work include determining the scale at which coastal and estuarine sub-populations of blue mussels can be considered self-recruiting, the degree to which these patterns are determined by physical processes and/or by larval behavior, and how patterns of exchange may vary over larger spatial and temporal scales. Answers to these questions will have a significant influence on efforts to conserve coastal and estuarine habitats and on the design and implementation of marine protected areas.