Seasonal migrations of American Lobster (Homarus americanus) in the Bay of Fundy: temperature and depth profiles quantified using archival satellite tags, and functional inferences tested using an individual-based model

Abstract

Ovigerous American lobsters, Homarus americanus, undertake seasonal migrations thought to maximize temperature experienced by their embryos. Using satellite tags, we tracked two ovigerous females from Grand Manan between September 2013 and July 2014. The tags surfaced near Beaver Harbour, NB and Port George, NS, 33 and 123 km from the tagging location, respectively. Recorded depth and temperature for both lobsters were remarkably similar, reflecting shallow-to-deep and deep-to-shallow migrations in the fall and spring, respectively. A change in water temperature appeared to trigger fall movements, but probably not spring movements. An individual-based model indicated that our lobsters experienced higher temperatures than virtual lobsters moving randomly or not at all, but lower than the maximum possible. This study provides novel insights into the nature and function of these seasonal migrations, which represents an essential first step in our ability to predict lobster movements and hatch location in a rapidly changing ocean.