Movements of egg-bearing American lobsters Homarus americanus during late stage brooding and hatching

Abstract

Although the large-scale movements of ovigerous (egg-bearing) American lobsters have been well-studied, their finer scale movements before, and during, the time when their eggs hatch are poorly understood. In this study, acoustic telemetry was used to track 12 ovigerous lobsters, carrying late-stage eggs, near the Isles of Shoals in the southern Gulf of Maine. In the spring of 2016 and 2017, lobsters were captured, fitted with acoustic tags that transmitted both depth and activity data, and released within an array of receivers. Eleven of the 12 lobsters moved from relatively shallow water (12 m) to deeper water (>29 m) approximately 2 wk prior to the time when their eggs were predicted to hatch. Four of these lobsters were within the array when their eggs most likely hatched, while 8 left the array towards even deeper water (>35 m). These data, taken together with previous data from research traps, suggest that egg-bearing lobsters tend to move to deep water prior to the time when their eggs are due to hatch, which may be beneficial for the dispersal and survival of their larvae.