Ornella Céline Weideli (PhD Candidate)

PSL Research University

EPHE-UPVD-CNRS, USR 3278 CRIOBE

Université de Perpignan, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France

 

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PROJECTS

PROJECTS

Photo © Malini Pittet | SOSF

Overview

I'm a biologist that is passionate about the Ocean and marine predators. I'm drawn towards sharks, especially to juvenile shark, their ecology and conservation.   

Population characteristics

From the over 450 extant shark species, only limited information is available on the juvenile life-stage. In many shark species, simple information such as location and time of birth, as well as birth size and early growth rates are still missing. Since this information is inevitable for their protection, we started collecting population characteristics from two shark species: the blacktip reef shark, Carcharhinus melanopterus and the sicklefin lemon shark, Negaprion acutidens.

Both species use shallow nearshore areas to give birth to their pups. While numerous areas are known where blacktip reef sharks occur, there is only a limited number of habitats, where both species coexist and therefore overlap in their young shark habitat. One of these places is the remote and uninhabited St. Joseph atoll in the republic of Seychelles.  

Photo © Ornella Weideli | SOSF

Photo © Ornella Weideli | SOSF

Photo © Michael Scholl | SOSF

Niche ecology

Having two juvenile shark populations sharing a small habitat such as St. Joseph atoll allows us to investigate how natural resources (habitat and prey resources) are partitioned between and within the two species. In other words, I am highly interested how they can grow up in the same habitat without out-competing each other. 

For more information on my project check out the D'Arros Reserach Centre and my publications for upcoming findings on these two shark population. 

Photo © Ryan Daly | SOSF

Study species

Blacktip reef sharks, Carcharhinus melanopterus

One shark species that uses shallow coastal areas for their pups the blacktip reef shark, Carcharhinus melanopterus. It's a widespread, medium sized shark with black fin tips (hence its name). They are frequently found on shallow coral reefs, reef flats or close to drop offs. Population characteristics (e.g. size at birth and maturity) vary significantly with location (to read more about this subject, see Mourier et al. 2012).

Sicklefin lemon shark, Negaprion acutidens 

The sicklefin lemon shark, Negaprion acutidens is a large bodied shark that also uses shallow nearshore areas for their pups. As opposed to blacktip reef sharks, the sicklefin lemon shark is a rare species and is assessed as vulnerable by the IUCN Red List.  

Photo © Ryan Daly | SOSF