THE STRUCTURE AND FUNCTION OF SOCIAL NETWORKS IN A MARINE PREDATOR

Across a range of taxonomic groups animals form complex, heterogeneous networks through repeated social interactions. These social networks may comprise tens to thousands of individuals occupying positions of variable spatial and temporal connectivity. In recent research, assortative mixing within animal social networks has been attributed to sex- and age-related homophily in bottlenose dolphins (Tursiops spp.), cooperation in guppys (Poecilla reticulate) and anti-predator defence mechanisms in numerous other group living species. Aside from novel studies on female baboons (Papio cynocephalus) however, there is distinct paucity of research on the fitness consequences of forming social bonds with conspecifics. In marine organisms particularly, it is still poorly understood how specific network attributes, such as linkage between group mates, reflect individual fitness and success. The examination of social structure in group-living animal populations is also crucial to our understanding of their spatial and temporal distribution, information transfer and spread of disease within a species.

Despite a wealth of evidence to suggest that numerous species of elasmobranchs aggregate in large numbers, we still know very little about what drives marine apex predators to form such aggregations or how they are structured. Elasmobranchs possess a relatively larger brain mass:body mass ratio when compared with teleost fish. We predict therefore, that elasmobranchs have greater potential for the formation of complex social structures and hierarchies. The aim of the proposed research is to examine the construction and function of social networks for small-spotted catshark Scyliorhinus canicula aggregations on three different scales. This will enable us to:

1. establish the effects of sex, age class, relatedness and familiarity on the social structure and;

2. determine how network position may confer individual costs/benefits.

People involved: David Jacoby, Professor David Sims (MBA), Dr Darren Croft (University of Exeter).

Funding: Fisheries Society of the British Isles Ph.D Studentship.