Seasonality and site fidelity of the zebra shark, Stegostoma fasciatum, in southeast Queensland, Australia
Dudgeon, CL and Lanyon, JM and Semmens, JM, Seasonality and site fidelity of the zebra shark, Stegostoma fasciatum, in southeast Queensland, Australia, Animal Behaviour, 85, (2) pp. 471-481. ISSN 0003-3472 (2013) [Refereed Article]
Copyright 2012 The Association for the Study of Animal Behaviour
Site fidelity and migratory movements of vertebrate animals occur at many spatial and temporal scales.
Larger migratory movements tend to occur in species that live in seasonal environments in which food
supplies vary markedly, while species found in thermally stable environments are more site-attached. In
the marine environment, seasonal migrations are often associated with predictable temporary aggregations
that have largely been targeted for exploitation. We employed passive acoustic telemetry to
investigate inter- and intraseasonal site fidelity of zebra sharks to an aggregation site in southeast
Queensland, Australia, close to the southern latitudinal extent of this speciesí range. We tracked 10 zebra
sharks over two aggregation seasons (21 months). We applied a generalized linear mixed-effects model
to investigate the presence/absence of these zebra sharks with respect to several environmental variables.
We found that different environmental factors were associated with site fidelity of zebra sharks at
different temporal levels and that these may be indicative of the mechanisms driving the movements.
Seasonal patterns may be driven by endogenous systems, and cues such as photoperiod and water
temperature are likely to be important. Intraseasonal patterns are more likely to be indicative of direct
behavioural responses to changes in environmental conditions such as increased wave heights, as well as
foraging bouts away from a core refuge. Understanding the relative contributions of these environmental
parameters, as well as biological factors, will be important for making predictions of site fidelity and
movements of migratory marine vertebrates under differing future scenarios such as increases in sea