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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps14519

Influences of environmental and individual-level covariates on movement behaviour in American lobster, Homarus americanus

Cassandra A. Konecny*, David Cote, Jeremy Broome, Jean-Marc Nicolas, Paul M. Regular, Adam M. Cook, Fatemeh Hatefi

*Corresponding author:

ABSTRACT: Movements reflect important activities and life history events for animals and therefore understanding what influences movement in organisms is increasingly important as climate change alters environmental conditions at unprecedented rates. This has relevance for predicting the effects of climate change on fitness and interpreting stock status of species such as American lobster whose catchability is behaviourally mediated. We analyzed movement tracks from tagged lobster in a natural environment over short (10 days, n = 37) and long timescales (up to 7 months, n = 16), applying Hidden Markov Models to investigate the influence of individual-level and environmental covariates on movement patterns. We classified movement tracks to identify behavioural states through time and compared the distribution of states across habitats to understand how movement may relate to bottom composition. In the short-term analysis we found evidence for three behavioural states in American lobster, namely Sheltered, Exploratory, and Transit states. In the long-term analysis we found evidence of Sheltered and Exploratory states, but the Transit state was absent. Movement parameters were shown to vary across temperature, with higher velocities and more tortuous movements at higher temperatures. Our results demonstrate that lobster spend most of their time Sheltered with state probabilities being altered by diel period, time since release, sex, carapace length, temperature, and tide trend. Further, mobile states were typically observed in areas of low algal cover. Our results underscore the importance of environmental and individual-level factors in understanding lobster movement and suggest that such factors could obscure population depletion if not accounted for in a warming environment.