Gastric Evacuation Rates of Spiny Dogfish, Goosefish, and Summer Flounder: Implications for Multispecies Models

Abstract

AbstractThe gastric evacuation rates of Spiny Dogfish Squalus acanthias, Summer Flounder Paralichthys dentatus and Goosefish Lophius americanus held at two different temperatures were determined in the laboratory by gastric lavage. Overall, exponential models provided the best fit for the evacuation rates. The Spiny Dogfish, an elasmobranch, evacuated more slowly than the Summer Flounder (a teleost) but the Goosefish, also a teleost, had the slowest evacuation rate of the three species. The Goosefish evacuation rate was nearly ten times slower than that of Summer Flounder. Evacuation was more rapid at the higher temperature tested in all three species. At 15°C, Summer Flounder had the highest average evacuation rate (0.094 exponential rate of decline), followed by Spiny Dogfish (0.063 exponential rate of decline), and then Goosefish (0.018 exponential rate of decline). Among the three species, activity levels and feeding behaviors are also very different, contributing to differences in evacuation rate. Species‐specific parameters of evacuation rate should be considered to better inform multispecies and ecosystem models and to more accurately estimate consumption and prey removal rather than using broad taxonomic groupings as in current common practice.