R/FISH-98 a

Strategic focus area:

Description:

*This project is a continuing project initially funded through award NA05OAR4171042 (year one) and currently funded through award NA10OAR4170072 (year two)*

OBJECTIVES: Our work seeks to test three fundamental hypotheses relating to the importance of intrapopulation biodiversity in spawning and early life history dynamics to the resilience of exploited natural resources using striped bass as a model population. The objectives include: 1) Does reproductive diversity influence recruitment potential? 2) Does phenotypic selection during early life cause the representation of maternal lines in the egg and juvenile stages to differ? 3) Do striped bass early YOY undergo deliberate retentive or dispersive behaviors resulting in two broadly classified contingents corresponding to two modalities in nursery habitat use?

METHODOLOGY: We will address our objectives by combining traditional approaches to studying the early life history of fish with those from the field of otolith microchemical analysis and modern molecular genetics. All work will be based on existing samples collected from the Patuxent River in 2007, and new sampling proposed herein for 2009. We will address the first two objectives characterizing sibship groups in eggs and later life stages in both 2007 and 2009 to test specific hypotheses regarding the maternal diversity, egg production and recruitment. This work requires application of maternal typing using techniques developed with existing MDSG PD funds that involves amplified, sequenced mtDNA isolated individual eggs, larvae and juveniles. The third objective requires microchemical analysis of otolith structure and birthdate frequency analysis. We have experience with application of all proposed protocols and laboratory techniques.

RATIONALE: When appropriately managed, the resiliency of Chesapeake's living resources to anthropogenic stress and climate change is remarkable. For example, striped bass is a dramatic success story of species recovery. But, although not realized at the time, the strong recruitments that lead to this success relied on the diversity in age structure within the population. We argue that biodiversity within population's genetic, demographic and complex life cycles of which striped bass serves as an example, is an overlooked but central factor in promoting population resiliency. Moreover, as anthropogenic stresses on all living resources in the Chesapeake Bay and other coastal ecosystems are likely to increase in the future, it is important that we seek to understand how such intra-population variability contributes to sustainability and resiliency in the resources. Here, we seek to quantify the contribution of intra-population diversity among the characteristics of spawning females and their offspring on population resilience using striped bass as a model species.