Habitat-specific monitoring documents dramatic changes in habitat use and ecology of a data-rich fisheries species, American lobster
Date:
Abstract: The American lobster, Homarus americanus, is among the most valuable fisheries species in North America. It is also among the best studied benthic marine invertebrates in the world having been studied and detailed in publications for over 35 years. The state of Maine conducts five annual surveys capturing population dynamics at different lobster life stages. Our study revisited 20 long-term monitored sites in 2019 and 2021 that were last sampled in 2000. American lobster was known to dwell in shelters and populations being historically concentrated in shelter-providing boulder habitat. Surprisingly, we recorded fundamental changes in lobster habitat use and distribution. Specifically, population densities in boulder habitats and rock shelter occupancy declined in recent years while densities on featureless habitats increased. These demographic changes may be driven by reduced intraspecific competition resulting from lower population densities and declines in smaller size classes. Despite the American lobster being extremely well-studied, it required our in-situ, habitat-specific surveys to document these significant shifts in lobster ecology. Moreover, these shifts have implications for how we interpret other lobster surveys. These findings underscore the importance of habitat-specific monitoring within a finer spatial scale to incorporate these continued ecological changes, especially with climate change, into decision-making processes. Authors: Jarrett, R., Brady, D., Steneck, R.
Ph.D. Dissertation Research at the University of Maine