Presenter: Alexander Ascher (University of Maine)

Description:
Despite the record abundance of egg bearing female American lobster (Homarus americanus) in the Gulf of Maine, benthic recruitment of young-of-year lobster has paradoxically been declining over the past decade. In this study, we investigated the hypothesis that the recruitment decline is the result of larval food limitation due to changes in the pelagic food web. We present a novel gut content analysis utilizing eDNA technology paired with traditional microscopy to determine the diet of field-caught larval stages. In addition, we use a combination of laboratory and field observations to determine the nutritional status of field-caught larvae and their susceptibility to starvation at different developmental stages. Initial results from laboratory trials suggest that earlier larval stages are much more susceptible to food limitation than later stages. While lipid contents of field-caught late stage larvae compared favorably to that of well-fed laboratory-reared larvae, supporting the conclusion that larval lobsters may not be food limited in the later stages, incoming data on early stage larval lipid content will provide information on whether food limitation is more important at this stage, as we have hypothesized. These results are discussed in light of climate change-related regime shifts affecting the abundance and diversity of zooplankton assemblage in the Gulf of Maine over the past decade.