Mazzini, Alexia
(2023)
Historical ecology of the Mediterranean population of Great White Shark, Carcharodon carcharias.
[Laurea magistrale], Università di Bologna, Corso di Studio in
Biologia marina [LM-DM270] - Ravenna, Documento full-text non disponibile
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Abstract
The Great White Shark Carcharodon carcharias, as many large sharks, is threatened by human
impacts. Presently it is considered as Critically Endangered in the Mediterranean Sea and
Endangered in the rest of the World by the IUCN. Its ecological role as top predator is essential
in maintaining the coastal and pelagic ecosystem function, therefore strong efforts have been
made worldwide towards their conservation, including the implementation of knowledge and
empirical data on migratory behaviour and feeding ecology.
In this perspective, the present thesis aims to understand the historical ecology of the
Mediterranean population of Great White Shark taking advantage from the multi-element
analysis of stable isotopes (i.e. carbon, nitrogen, zinc and strontium) of several historical
remains archived in civic and academic Italian museums and private collections. Since Great
White Shark is a large epipelagic migratory shark, the first point of the research is to provide
information about the movements between Mediterranean and adjacent Atlantic Ocean by the
estimate of the isotopic composition of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) from the
collagen of jaws, teeth, and vertebrae. Additional analyses of the ontogenetic shifts were carried
out by a sequential carbon, nitrogen, and zinc analyses of four vertebrae belonging to a single
individual archived in the Massimo Sella collection at the University of Bologna; in addition,
one fossil tooth from Borgo Tossignano was dated back using 87Sr/86Sr isotope composition.
The results indicated that these multidisciplinary analyses need to be improved to assess the
correct isotopic footprint and wonder to understand the historical ecology of Great White Shark
population in the Mediterranean Sea, but it is a very promising methodology that has already
made it possible to understand that white sharks in the Mediterranean Sea are not an isolated
population.
Abstract
The Great White Shark Carcharodon carcharias, as many large sharks, is threatened by human
impacts. Presently it is considered as Critically Endangered in the Mediterranean Sea and
Endangered in the rest of the World by the IUCN. Its ecological role as top predator is essential
in maintaining the coastal and pelagic ecosystem function, therefore strong efforts have been
made worldwide towards their conservation, including the implementation of knowledge and
empirical data on migratory behaviour and feeding ecology.
In this perspective, the present thesis aims to understand the historical ecology of the
Mediterranean population of Great White Shark taking advantage from the multi-element
analysis of stable isotopes (i.e. carbon, nitrogen, zinc and strontium) of several historical
remains archived in civic and academic Italian museums and private collections. Since Great
White Shark is a large epipelagic migratory shark, the first point of the research is to provide
information about the movements between Mediterranean and adjacent Atlantic Ocean by the
estimate of the isotopic composition of carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) from the
collagen of jaws, teeth, and vertebrae. Additional analyses of the ontogenetic shifts were carried
out by a sequential carbon, nitrogen, and zinc analyses of four vertebrae belonging to a single
individual archived in the Massimo Sella collection at the University of Bologna; in addition,
one fossil tooth from Borgo Tossignano was dated back using 87Sr/86Sr isotope composition.
The results indicated that these multidisciplinary analyses need to be improved to assess the
correct isotopic footprint and wonder to understand the historical ecology of Great White Shark
population in the Mediterranean Sea, but it is a very promising methodology that has already
made it possible to understand that white sharks in the Mediterranean Sea are not an isolated
population.
Tipologia del documento
Tesi di laurea
(Laurea magistrale)
Autore della tesi
Mazzini, Alexia
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Ordinamento Cds
DM270
Parole chiave
White sharks, Stable isotopes, Historical ecology, Historical samples, Mediterranean Sea, Zinc
Data di discussione della Tesi
28 Marzo 2023
URI
Altri metadati
Tipologia del documento
Tesi di laurea
(NON SPECIFICATO)
Autore della tesi
Mazzini, Alexia
Relatore della tesi
Correlatore della tesi
Scuola
Corso di studio
Ordinamento Cds
DM270
Parole chiave
White sharks, Stable isotopes, Historical ecology, Historical samples, Mediterranean Sea, Zinc
Data di discussione della Tesi
28 Marzo 2023
URI
Gestione del documento: