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PhD Studentship: The Structure and Function of Social Networks in a Marine Predator

David Jacoby

Marine Biological Association & University of Exeter

Supervisor(s): Darren Croft and David Sims

It is well documented that many species of shark exhibit frequent, and often sexually segregated, aggregation behaviour during the resting phase of their diel cycle. This behaviour has been linked in the past to habitat or environmental preferences, foraging opportunities and reproductive behaviour, but little attention has been paid to the role of social preferences in these aggregations. Social network analysis is a theoretical framework which has been recently adapted to explore how animals interact through space and time, and consequently what impact this has on the transmission of information or disease between conspecifics. With elasmobranchs exhibiting a larger brain mass to body mass ratio than teleost fish, there is potential for the formation of complex social systems within these aggregation events but this has never been examined.

This project uses the small spotted catshark (Scyliorhinus canicula) as a model species with which to study social preferences and network construction in elasmobranchs. Using repeatable and controlled laboratory network experiments this project aims to determine the role of kinship and familiarity on the development of social structure in this species and assess how habitat complexity is likely to influence decisions about social behaviour. To give context to the laboratory studies, nearly 50 adult catsharks have been tagged acoustically and are currently being tracked in the wild with passive telemetry receivers on the seabed. Network analysis will not only shed light on the degree of co-occurrence of these sharks in the wild but will also be adapted to understand how environmental variables influence the ways in which individual, or groups of, animals move within and between habitat areas. The technique adapted for this study will have implications for the analysis of telemetry data from a wide variety of both marine and terrestrial animals.

Publications:

Griffiths, A.M., Jacoby, D.M.P., Casane, D., McHugh, M., Croft, D.P., Genner, M.J. & Sims, D.W. First analysis of multiple paternity in an oviparous shark, the small-spotted catshark (Scyliorhinus canicula L.). Journal of Heredity (in press) doi: 10.1093/jhered/esr112

Jacoby, D.M.P., Croft, D.P. & Sims, D.W. Social behaviour in sharks and rays: analysis, patterns and implications for conservation. Fish and Fisheries (in press) doi: 10.1111/j.1467-2979.2011.00436.x

Jacoby, D.M.P., Busawon, D.S. & Sims, D.W. (2010). Sex and social networking: the role of male presence on social structure of female shark groups. Behavioral Ecology 21, 808-818.

Contact:

The Marine Biological Association of the UK
The Laboratory
Citadel Hill
Plymouth
PL1 2PB
UK
Email: david.jacoby@mba.ac.uk

http://www.mba.ac.uk/simslab/peop_jacoby.html

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