DRERIP Ecosystem Conceptual Model: Potamcorbula amurensis

Potamocorbula amurensis is a pest in the San Francisco Estuary (hereafter SFE) due to its ability to heavily graze pelagic food resources and its accumulation of toxic substances that are then moved into the food web through its predators. We begin by describing what we know of its life history and establish its life cycle within the framework of the ecological setting of the SFE. This model should be used within the context of a thought experiment, as there is not enough known about the species to design a strategy to control it in the SFE or Delta. The ultimate purpose of this conceptual model of Potamocorbula amurensis is to explore its weaknesses.

The geographic focus of the DRERIP models is the Delta. However we examine the life history patterns of Potamocorbula amurensis as far down bay as San Pablo Bay for two reasons. First, because some of the largest ecosystem effects attributed to P. amurensis are its consumption of pelagic carbon resources, it is necessary to include areas adjacent to the Delta due to the effects of tidal dispersion. Second, many of the life cycle patterns that are visible in San Pablo Bay are transferrable to upstream locations during drought periods.

Finally, we expect this model to evolve as a result of the many ongoing studies on P. amurensis. Some of the data shown in this discussion are the direct result of current CALFED studies being done jointly by California Department of Water Resources (EMP Program D. Messer and K. Gerhts) and the USGS (Analysis of Archived Samples to Assess Patterns of Historic Invasive Bivalve Biomass). Our co-investigators on that study have been gracious in allowing us to show some of that data here, before it has been published.

We start the model discussion with a brief description of the taxonomic status of this bivalve because the utility of the literature available to us is based on assumptions of the correct identification. We also very briefly describe its introduction into the SFE as a reminder of the facts about its invasion.