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Lemon Shark Family Tree

Overview:
Our current research is based on the lemon shark family tree, which has enabled us to extend our previous research on mating and foraging behaviour. Current research includes examining how common natal philopatry is at the Bimini nursery. Additionally, in conjunction with stable isotope analysis, we are examining whether or not foraging behaviour has a genetic basis (i.e. whether or not it is heritable) and can explain the small, slow growing juvenile sharks that are favoured at Bimini. Finally, we wish to expand sampling in other nurseries to determine whether or not Bimini adult females occasionally give birth at nearby nurseries.

Research Questions

1. How common is natal philopatry at the Bimini nursery? Do Bimini females give birth at nearby nurseries?

2. Do juvenile lemon sharks forage preferentially in the mangroves or seagrass, and does this ultimately influence their size and growth or chances of survival?

3. Do female lemon sharks choose their mates in order to maximize genetic diversity at MHC loci?

Conservation Importance

The nursery areas of most coastal sharks are typically in state waters where state jurisdiction applies, but feeding grounds, mating areas, and the migratory paths in between can often be in federal waters. Data on the frequency of natal philopatry in the lemon shark is therefore needed for the effective protection of such species and to better preserve these associated nursery grounds as essential fish habitat. 

Preliminary Findings

Natal philopatry

We found three cases of female lemon sharks born at Bimini coming back to Bimini to give birth to their own young, the first cases in any shark species.

 

Isotope Work

Thus far stable isotopes indicate that the seagrass and mangrove environments carry distinct isotopic signatures, and that these are reflected in two distinct groups of juvenile lemon sharks at Bimini that appear to feed predominantly in mangroves or seagrass.