Shark Personality

Personality describes the fact that within a population, individuals consistently differ in their behaviour. While personality research was first applied to humans, a wide variety of studies now support its existence in non-human animals. The occurrence of personality in animal populations has been widely documented; however its ecological and evolutionary consequences remain unexplored. In order to address this gap in our knowledge it is important to combine captive experiments with observations in the wild. This approach will ensure findings that reflect natural behaviour and conclusions that are ecologically relevant. However, the logistical and practical challenges of such a multi-faceted approach have led to a taxon-specific and small animal bias for personality studies. In this project, we propose to use wild juvenile lemon sharks to address the ecological consequences of personality. Juvenile lemon sharks in the study site can be captured in large numbers, are resilient in captivity and can be recaptured and tracked for ~4 years in the wild. Using an established methodology, we have started testing the sharks for traits in captivity and use acoustic telemetry (to follow sharks in the wild), stable isotope analysis (diet), DNA analysis (heritability), and community assessment methods in order to investigate the link between personality and ecology. This study will address one of the big challenges of animal personality research and will provide new insights into elasmobranch conservation and behaviour.

    •    Investigate how personality observed in captivity is linked to natural behaviour.
    •    Determine the link between personality, habitat use and niche specialization.
    •    Understand the trade-off mechanisms which explain how different personality phenotypes are maintained in a population.
    •    Estimate heritability and genetic correlations in personality.

This project presents a unique opportunity to advance our knowledge in the field of animal personality. Indeed, the study site and species provide us with an ideal framework to conduct large scale experiments in captivity and in the wild. Each year, since 1995, the Bimini JLS population is captured with 99% efficiency using gillnets, each individual can be tested for behaviour traits in semi-captive environments; furthermore, potential recaptures the following years allow the retesting of individuals.  In 2014, 148 juvenile lemon sharks were captured in a twelve days fishing effort and 68 of them were recaptures from previous years. With genetic samples taken on every individual, as well as tissue samples for stable isotope analysis and other measurements (total length, sex, etc.) this population has now a substantial amount of data available for scientific studies. It is for instance possible to study how behaviour traits are related to growth rate, their habitat-use as well as heritability. In addition, the juvenile lemon sharks of the Bimini population have a daily home range of a few hundred squared meters and aggregation areas are found in the habitat, providing us with the unique opportunity to observe behaviour types in the context of free-ranging predators.
Anthropogenic pressure has propagated on land, in coastal areas and in the open ocean, leading to a change in ecosystems via the disappearance of many species. Large marine vertebrates (i.e. sharks, mammals, turtles, seabirds) tend to be particularly vulnerable to this pressure due to their complex life history traits such as low fecundity, late sexual maturity, long life spawns or extended migrations. Many elasmobranch populations are threatened by directed fisheries or by-catch mortality but also by marine pollution or by habitat degradation. To date, sixty-four species of elasmobranchs are considered endangered or critically endangered by the International Union for Conservation of Nature and Natural Resources. Elasmobranchs are often considered as ecological keystone species in their habitats and their disappearance can lead to cascading effects affecting the whole ecosystem including lower trophic levels. For instance, just like other apex predators, sharks influence their own prey population leading to anti-predatory behaviours shaping the rest of the ecosystem (i.e. avoidance of certain areas by prey, selective foraging etc.). Given their ecological importance and the multiple threats they face, it is important to develop a better understanding of shark behaviour and personality to enhance conservation.

 


Principle Investigator:

Félicie Dhellemmes - Bimini Biological Field Station/Humboldt Universität zu Berlin
 
Collaborators:
Prof. Jens Krause - Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB)/Humboldt Universität zu Berlin
Dr. Tristan Guttridge - Bimini Biological Field Station
Dr. Samuel Gruber - Bimini Biological Field Station
For the DNA extraction: Dr. Kevin Feldheim (Museum of Natural History (Chicago, IL)) and Dr. Ned Dochterman (North Dakota University)
For the stable isotope analysis: Dr. Nigel Hussey (University of Windsor)

Close content
Open content