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GLIN==> Two Seminars this Week (Ann Arbor)

My apologies for this last minute notice. GLERL is hosting two NOAA - U of M Great Lakes Seminars Series seminars this week:

10:00 a.m., Tuesday, November 27
GLERL Conference Room 105

Title: "The relative influence of landscape configuration and inundation on brown shrimp production in northern Gulf of Mexico salt marshes"

Speaker: Dr. Brian Roth,
Department of Oceanography and Coastal Sciences
Louisiana State University

I used a spatially explicit individual-based model to investigate the relative influences of inundation and habitat fragmentation on brown shrimp (Farfantepenaeus aztecus) production in northern Gulf of Mexico (NGOM) salt marshes. The model simulates a population of brown shrimp from their arrival in Spartina salt marsh as post-larvae to their emigration as sub-adults. I quantified production in terms of sub-adult export and trophic transfer (total shrimp mortality). I utilized a factorial design to simulate shrimp on all combinations of four maps that represented an idealized progression of habitat fragmentation and four inundation regimes from each of two locations in the NGOM (Louisiana and Texas). I also quantified the configuration of the marsh landscape to determine if specific metrics could be utilized as a proxy for shrimp production. The results indicate that inundation is more important than landscape configuration for determining shrimp production, but that landscape configuration has a strong influence on shrimp production within a single inundation regime. Inundation affected all three measures of shrimp production, primarily due to decreased mortality incurred when shrimp have access to vegetation through marsh flooding. Although the model performs well in comparison to empirical estimates of shrimp abundance and spatial distribution, future investigations will need to consider the dynamic relationship between inundation and landscape configuration to accurately predict shrimp production over longer time scales.


10:00 am, Thursday, November 29
GLERL Conference Room 105

Title: "Untangling the relationships between variability in the marine environment, population dynamics, and community structure"

Speaker: Dr. Brian Wells, Long Marine Laboratory,
University of California, Santa Cruz;
NOAA Fisheries, Fisheries Ecology Division, Santa Cruz

Researchers accept that variability in the marine environment affects the productivity of populations, communities, and ecosystem stability. The challenge to conservation biologists is not only in recognizing the complicated mechanisms and interactions between environmental variables and the biological responses, but also in quantifying these factors in such a way as to incorporate the results into a management framework. Here, I broadly demonstrate, through novel statistical and field approaches, how the environment drives aspects of production for krill, fish, and seabirds along the northern and central California coasts. I focus on a list of ecological factors that relate to productivity: mortality, fecundity, age at maturation, distribution, juvenile dispersal, and ecosystem state. I show that variability in maturation age and growth rates of Chinook salmon relate to environmental variability in a predictable way. Specifically, an environment conducive to greater primary productivity during the spring promotes growth and, therefore, maturation during the next year. However, the mechanisms differ between regions along the northeast Pacific coast such that the distribution of the fish must be known to fit models appropriately. These findings can be used to adjust maturation rate schedules and better estimate ocean abundance of a cohort. I also show a novel approach to describing dispersal of juvenile rockfishes along the central California coast that will assist in determining habitat-specific mortality and condition. In doing this, I use remotely-sensed sea surface temperature data to define distinct open-ocean habitats (e.g., upwelling regions, plumes). Then, I combine these spatially-referenced data with shipboard collections of water and fish to develop distinct chemical signatures on otoliths that can be used to retrospectively determine habitat associations of juvenile pelagic rockfishes before they settle into the Monterey Bay region. Finally, I demonstrate that the production of a key indicator trophic chain (i.e., krill, rockfish, seabirds) within the larger food web can be related, in a predictable fashion, to the environment over a thirty-year period. The results of this work can be applied directly to improve management of rockfishes by improving estimates of year-class strength, and, most importantly, these results provide an indicator of ecosystem state and productivity.

For directions, see

David F. Reid, Ph.D.
Director, NOAA National Center for Research on Aquatic Invasive Species (NCRAIS)
Senior Research Scientist, Nonindigenous Species Program
U.S. Department of Commerce
National Oceanic and Atmospheric Administration
Great Lakes Environmental Research Laboratory
2205 Commonwealth Blvd.
Ann Arbor, MI 48105-2945
Voice: 734-741-2019
FAX: 734-741-2055
GLERL home page:

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