Effects of environmental variables on the movement and space use of coastal sea snakes over multiple temporal scales

Abstract

Natural and anthropogenic changes in the marine environment can strongly influence the biology and behaviour of coastal organisms. Understanding how animals that rely on these habitats respond to environmental change is crucial to inform when management actions should be implemented to mitigate or reduce impacts. Here passive acoustic telemetry was used to monitor the movements of spine-bellied sea snakes (Hydrophis curtus) within a coastal ecosystem to define activity patterns in relation to environmental conditions. Presence, movement and three-dimensional home range metrics calculated from monitoring data were tested against environmental (water temperature, atmospheric pressure, wind speed, accumulated rainfall and tidal range) and biological (snout-vent length) factors on daily and monthly temporal scales to identify key environmental drivers of movement and the use of space. A generalised linear mixed model (GLMM) framework using Akaike information criterion (AIC) indicated that tidal reach and atmospheric pressure strongly influenced the daily presence and movements of tagged individuals, respectively. Accumulated rainfall significantly influenced the volume of space used on a monthly timescale. This study presents first estimates of three-dimensional home ranges of sea snakes as well as novel information on how environmental variables influence daily and monthly presence, movements and use of space of coastal sea snakes. These data are important in further understanding the ecology of sea snakes and can inform future management actions for this poorly studied taxon in the light of increased environmental and anthropogenic disturbances.