Scaling restoration of American lobsters: Combined demographic and discounting model for an exploited species

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Ecological theory does not currently allow precise predictions of the consequences of ecological restoration. Ecological restoration and species enhancement projects could be profitably used to test theoretically based predictions, but only if theory were first applied to develop quantitative predictions suitable for testing. Here, we review what is known about factors limiting population size and production of the American lobster Homarus americanus, and use that information to construct a demographic life-table model of population dynamics. We then use the model to evaluate alternative options for enhancing lobster population size and production. Because this species represents an example of a population subjected to intense human exploitation as a target of commercial fisheries, which has stimulated much research on its biology, demographic modeling is facilitated. Furthermore, intervention into the fishery provides a viable restoration option available only to exploited species. We apply the economic concept of discounting (of future pay-back in the form of restoration, analogous to being paid interest on a loan) to allow quantification of the scale of restoration needed to compensate for both the magnitude of the estimated loss of American lobsters and the time lags between loss and restoration following a major oil spill. Quantification of benefits is rarely performed for restoration projects to guide compensation for natural resource damages caused by environmental incidents. The methods and approach developed here can help address this past failure in order to provide compensating ecological and human services equal to those lost. The approach represents a significant step forward in conceptually and quantitatively addressing restoration needs. The methods may be applied to other species, especially those that are exploited by humans, but also others that can feasibly be restored to mitigate impacts of adverse environmental events.

Publication Title, e.g., Journal

Marine Ecology Progress Series