Lobster postlarval and early juvenile ecology: Interacting effects of physical processes and behaviour

Physical and biological processes interact during early life stages to determine the distribution and abundance of larvae of many marine benthic species, including the commercially and ecologically important American lobster, Homarus americanus. Following planktonic development, lobster postlarvae seek benthic habitat to occupy during a juvenile phase. Past studies of lobster settlement and post-settlement behaviour have rarely considered the effects of physical factors. To test whether lobster settlement is affected by flow, I conducted flume experiments. Flow increased settlement by increasing substrate encounter through passive deposition and modification of searching behaviours. To examine shelter fidelity of recently settled juvenile lobster, the behavioural response of 3-month-old lobsters to shelter warming and cooling was tested. Lobsters behaved aversively in response to cooler temperatures, and abandoned their shelter to move to warmer water. These studies of the interactions between physical factors and early lobster behaviour enhance our understanding of spatial and temporal variability in populations and our ability to identify habitats for conservation.