Striped bass recruitment

Like many other estuarine ecosystems, the Chesapeake Bay has been exposed to a diverse array of anthropogenic stresses including recent climate change. Yet, with some notable exception, the resiliency of the Chesapeake’s living resources to these stresses is remarkable. Biodiversity within populations – genotypic and phenotypic diversity, age structure and complex life cycles – has been hypothesized to play a central role in this resiliency.

Striped bass (Morone saxatilis) is one example for which an increased understanding of intra-population biodiversity would be of benefit. It has previously been demonstrated that differences in maternal characteristics influence patterns of larval survival and presumably recruitment. Recently, management agencies have recognized the potential to conserve this phenotypic diversity to promote long term sustainability. In this research we are investigating two principal modalities related to recruitment in striped bass as mechanisms that underlie this species observed resilience against annual (weather) and decadal (climate) environmental variability: 1) diversity of maternal lines as a function of spawning time, and 2) dispersive and retentive migration patterns in juveniles. In a collaboration with Dave Secor (CBL) and Al Place (IMET) we using of genetic markers and otolith analyses as both real-time and retrospective diagnostics of these modalities at key points in the life cycle of striped bass: egg, larva, and young-of-the-year juveniles.

From 2007-2009 we characterized the phenotypic distribution of spawning females, assessed egg and larval abundance using bongo nets and sampled juveniles throughout the summer and early autumn using seines. From these samples we have characterized variability in the spawning energetics of females in the different years, estimated hatch date frequencies in the different years and are currently quantifying the relative survival of different sibling groups in the population. We are seekign to test key hypotheses regarding spawning including

1) Are sibling groups equally represented in survivors?

2) Does peak sibling diversity coincide with peak egg abundance?

Striped bass presentations

Peer & Miller (2010). Maternal effects on striped bass larvae - AFS poster

Peer et al (2010). Spawning energetics talk - AFS 2010

Williams et al. (2010) Heteroplasmy poster - AFS 2010

Last revised: 12/16/2010