École Pratique des Hautes Études (EPHE)
CRIOBE - Perpignan
USR3278 CRIOBE EPHE-CNRS-UPVD
58 Avenue Paul Alduy
66860 Perpignan Cedex
Domaines de Recherche:
- Community Biology
- Trophic Ecology
- Special interest in Shark Biology and Ecology
Soutenance de Doctorat | 11 Juin 2020
Titre : Mechanisms of coexistence: A multi-disciplinary investigation of sympatric juvenile reef sharks
Abstract (Short) : In areas of sympatry, closely related and morphologically similar species are expected to occupy different ecological niches in order to avoid competition. However, without knowledge on competitive abilities (e.g. dominance hierarchies) and population characteristics (e.g., growth rates, fitness traits), the origin and the potential effects of niche pattern (segregation and overlap) are unknown. Within the scope of this PhD, juvenile blacktip reef sharks (Carcharhinus melanopterus) and juvenile sicklefin lemon sharks (Negaprion acutidens) were studied at St. Joseph Atoll, Seychelles and at Moorea, French Polynesia. Evidence suggests that juvenile blacktip reef sharks and juvenile sicklefin lemon sharks exhibit fine-scale segregation patterns as a means to avoid competition. In contrast, slight differences in population characteristics were more likely to be caused by prey availability, intraspecific competition, and anthropogenic impacts. This thesis highlights the importance of multi-disciplinary investigations to unveil the underlying mechanisms of coexistence, but future investigations - also including other study sites - are needed to further address these mechanisms.
Sélection de Publications
- Weideli, O.C., Papastamatiou, Y.P. Intestinal eversion in a pelagic shark evokes chase and bite attempts by large-bodied carangid fish. Journal of Ethology.
- Bouyoucos, I.A., Morrison, P.R., Weideli, O.C., Jacquesson, E., Planes, S., Simpfendorfer, C.A., Brauner, C.J., Rummer, J.L.. Thermal tolerance and hypoxia tolerance are associated in blacktip reef shark (Carcharhinus melanopterus) neonates. Journal of Experimental Biology. DOI: 10.1242/jeb.221937.
- Weideli, O.C., Kiszka, J.J., Matich, P., Heithaus, M.R. (2019) Effects of anticoagulants on stable isotope values (δ13C and δ15N) of shark blood components. Journal of Fish Biology. https://doi.org/10.1111/jfb.13982
- Weideli, O.C., Bouyoucos, I.A., Papastamatiou, Y.P., Mescam, G., Rummer, J.L, Planes, S. (2019) Same species, different prerequisites: investigating body condition and foraging success in young reef sharks between an atoll and an island system. Scientific Reports, doi: 10.1038/s41598-019-49761-2.
- Weideli, O.C., Papastamatiou, Y.P., Planes, S. (2019) Size frequency, dispersal distances and variable growth rates of young sharks in a multi-species aggregation. Journal of Fish Biology. doi: 10.1111/jfb.13968.
- Bouyoucos I.A., Weideli, O.C., Planes, S., Simpfendorfer, C.A., Rummer, J.L. (2018) Dead tired: evaluating the physiological status and survival of neonatal reef sharks under stress. Conservation Physiology. 6, coy053; doi:10.193/conphys/coy053
- Hussey NE, DiBattista JD, Moore, JW, Ward, EJ, Fisk, AT, Kessel, S, Feldheim ,KA, Gruber, SH, Guttridge, TL, Weideli, OC, and Chapman DD (2017) Risky business for a juvenile marine predator? Testing the influence of foraging strategies on size and growth rate under natural conditions. Proc. R. Soc. B 284: 20170166. DOI: 10.1098/rspb.2017.0166
- Weideli et al. (2015) A massive surgeonfish aggregation creates a unique opportunity for reef sharks. Coral Reefs, 34, 835.
I’m investigating how natural resources (habitat and diet) are partitioned between juvenile blacktip reef sharks, Carcharhinus melanopterus and sicklefin lemon sharks, Negaprion acutidens to elucidate new insights about coexistence, niche segregation patterns, and competition.