Analysis of fine-scale daily movement patterns of juvenile smalltooth sawfish within a nursery habitat

Published online on 20. February 2015

Analysis of fine-scale daily movement patterns of juvenile Pristis pectinata within a nursery habitat

Lisa D. Hollensead, R. Dean Grubbs, John K. Carlson, Dana M. Bethea

ABSTRACT:

1. Habitat use studies can be used to investigate ecological and behavioural patterns of animals and serve as useful tools for conservation planners. However, specific habitats essential to survival can be difficult to determine for highly mobile marine animals, especially when these species are rare or endangered.
2. Active acoustic tracking telemetry was used to determine daily activity spaces and rates of movement of juvenile smalltooth sawfish (Pristis pectinata) in critical habitat areas of south-west Florida, USA.
3. Activity space size and rates of movement were positively related with the size of the area where the animal was tracked. Overall, activity spaces were small and ranged from 0.07–0.17 km² using 95% minimum convex polygons, 0.01–0.16 km² based on 50% kernel density estimates (KDE), and 0.08–0.68 km² based on 95% KDE. Rates of movement ranged from 2.4 to 6.1 m min^–1.
4. There were no detectable differences in activity space or rates of movement between ebb and flood tide or high or low tide. Activity space decreased and rates of movement increased at night, possibly related to nocturnal foraging behaviour or predator avoidance. Comparisons of tracked animal locations and random locations suggested there was selection for those habitats in close proximity to mangrove shoreline.
5. Though daily activity spaces were small, juvenile smalltooth sawfish did exhibit a daily expansion in activity space over the monitoring period.

Aquatic Conservation: Marine and Freshwater Ecosystems, Early View Version, doi: 10.1002/aqc.2556

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