Biology, distribution and diversity of cartilaginous fish species along the Lebanese coast, eastern

310 Pages·2017·11.25 MB·English

by  Myriam Lteif

Délivré par
UNIVERSITE DE PERPIGNAN VIA DOMITIA

Préparée au sein de l’école doctorale

Energie et Environnement

Et de l’unité de recherche
CEntre de Formation et de Recherche sur les

Environnements Méditerranéens (CEFREM)
UMR 5110 CNRS UPVD

Spécialité : Océanologie

Présentée par Myriam LTEIF

BIOLOGY, DISTRIBUTION AND DIVERSITY

OF CARTILAGINOUS FISH SPECIES ALONG
THE LEBANESE COAST, EASTERN

MEDITERRANEAN

Soutenue le 22 Septembre 2015 devant le jury composé de

Eric CLUA, HDR, Délégué Régional à la Recherche et à la Rapporteur
Technologie (DRRT), Polynésie Française

Ghassan EL ZEIN, Professeur, Université Libanaise Rapporteur
Bernard SERET, Chercheur, IRD Museum d'Histoire Naturelle Examinateur

Philippe LENFANT, Professeur, HDR, UPVD Examinateur
Gaby KHALAF, Professeur, CNRS Libanais Directeur
Marion VERDOIT-JARRAYA, Maître de conférences, UPVD Co-directrice
To my parents, Imane and Issam
To my sister, Stephanie
To the love of my life, Salim

You all mean the world to me…
In loving memory of Hanna Kattoura
Two roads diverged in a wood, and I—
I took the one less traveled by,
And that has made all the difference.

Robert Frost
Acknowledgements
I would like to offer my deepest gratitude to Dr. Eric Clua and Professor Ghassan El Zein who
judged this work, Dr. Bernard Seret, Dr. Philippe Lenfant for their presence in the jury. They all
gave me the honor and pleasure of being present during my thesis defense and their remarks
were very beneficial to me.
I am indebted to Université de Perpignan Via Domitia (UPVD), especially the directors of the
Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), Serge
Heussner and Wolfgang Ludwig for welcoming me during my thesis. They offered a very
rewarding work environment.
My gratitude also goes to the Lebanese National Council for Scientific Research CNRS-L for
granting me a scholarship for a thesis project, as well as hosting me during the course of my
thesis in its National Center for Marine Sciences (NCMS) in Batroun.
I offer gratitude to my supervisor Professor Gaby Khalaf and my co-supervisor Dr. Marion
Verdoit-Jarraya because this thesis would not have been possible without their trust and support.
I thank them both for their guidance and for granting their vast experience, advice and
interpretations to help accomplish this work. It could not have been completed without their full
commitment, patience and kindness.
My thanks goes to Professor Jean Benkhelil and Professor Marie Abboud Abi Saab for their
continuous presence in my thesis committee.
My deepest gratitude goes to my friend and mentor, Dr. Rita Mouawad, for the hand she put in
the birth of this thesis, her persistent help in all times, and above all, her friendship. Her
continuous support, patience, motivation, and knowledge gave me strength throughout the course
of this thesis.
Similarly, I would like to thank all the staff of the CNRS-Lebanon for their warm welcome,
kindness and confidence. I would like to thank all the members of the NCMS in Batroun and
Jounieh, Lebanon. I would also like to offer my sincerest gratitude to Dr. Sherif Jemaa for his
nonstop support and help in sampling throughout the course of this thesis. My cordial gratitude
also goes to Dr. Mona Ibrahim for her maintained support.
In addition, I would like to thank Stefano Lelli, the coordinator of the PESCA-Libano project
which was carried out in the framework of the CANA project of CNRS. His help on the field and
with the survey data collection provided more study aspects during the course of this thesis.
My gratitude then goes to all my colleagues: Céline Mahfouz, Elissar Gemayel, Anthony Ouba,
Abed El Rahman Hassoun, Ali Badereldinne, Laury Acaf, Aurore Assaker; friends: Karine Hage
Maria Feghali and Rawa Fallah; and all whom I could not mention for their persistent support in
all times.
Last but not least, my deepest gratitude and love goes to my parents Imane and Issam Lteif and
my sister Stephanie for pouring their faith and support in me during all times.
Finally, I present the most profound gratitude to my fiancé Salim Kattoura. His presence in my
life and his great love granted me encouragement that allowed me to complete this work. He
coated me with love and affection during my most vulnerable and difficult moments.
Abstract
Facing the intensive fishing of marine species occupying high trophic levels, the establishment of
appropriate management measures is needed. The aim of this study is to contribute to a better
knowledge of cartilaginous fish in the Lebanese coastal waters, Eastern Mediterranean.
After a general introduction (Chapter I) presenting the context and objectives of the study, an
overview of the study site and diverse methods (Chapter II) (data collection, biological
measurements, statistical analyses etc.) are displayed. Data was collected from an experimental
survey in the framework of the CIHEAM PESCA-Libano project and periodic observation of
fisheries and catches of hired fishermen.
Chapter III presented a literature review on the biology, ecology and geographic range of
cartilaginous fish from the Eastern Mediterranean.
In the first part of Chapter IV, emphasis was placed on various aspects of spatial and seasonal
distribution, diversity, biology and ecology of these species. In this study, a total of 315
specimens of cartilaginous fish were sampled. These specimens constituted of 25 cartilaginous
fish species, including 11 shark species and 14 batoid species. No chimaeras were recorded. The
majority of the sharks sampled were Centrophorus granulosus, Galeus melastomus, Squalus
blainville and Mustelus mustelus. The majority of the batoids sampled were Rhinobatos
rhinobatos, Rhinobatos cemiculus, Torpedo marmorata, Torpedo nobiliana, Raja miraletus and
Raja clavata. These cartilaginous fish specimens were caught at depths ranging from 10 to 600
m majorly using longlines, then trammel nets and the least were caught using gillnets. The Catch
Per Unit Effort was used as an index of abundance and its spatial and seasonal variations were
analyzed. The spatio-temporal diversity was also estimated and the highest values were observed
in the southern region and during spring and winter. In the second part, different length-weight
relationships have been established for species with exhibiting 10 or more individuals (3 sharks
and 5 batoids).
Furthermore, a focus was placed on the biology and ecology of two commercially significant and
exploited species. The population biology of the batoid Rhinobatos rhinobatos (Chapter V) and
the shark Centrophorus granulosus (Chapter VI) were evaluated separately using individuals
from the two data sources combined (scientific and commercial). Finally, the last chapter
(Chapter VII) is devoted to the general discussion and perspectives of this study.
Keywords: Chondrichthyans; conservation; distribution; life history; Lebanon; Levantine basin
Résumé
Face à la pêche intensive des espèces marines de haut niveau trophique, l‘instauration de
mesures de gestion appropriées s‘avère nécessaire. L‘objectif de cette étude est de contribuer à
une meilleure connaissance des poissons cartilagineux dans les eaux côtières libanaises de la
Méditerranée orientale.
Après une introduction générale (chapitre I) introduisant le contexte et les objectifs de l‘étude,
vient la présentation du site d‘étude et des diverses méthodes employées (collectes des données,
mesures biologiques, analyses statistiques etc.) (chapitre II). Les données ont été collectées à
partir de captures expérimentales dans le cadre du projet scientifique "CIHEAM PESCA-Libano"
et d‘observations périodiques des poissons capturés par les pêcheurs et présents dans les
poissonneries.
Le chapitre III est dédié à une synthèse bibliographique sur la biologie, l‘écologie et la
répartition géographique des poissons cartilagineux de la Méditerranée orientale.
Dans une première partie du chapitre IV, l'accent a été mis sur les différents aspects de la
distribution spatiale et saisonnière, la diversité, la biologie et l'écologie de ces espèces. Au total,
314 spécimens de poissons cartilagineux ont été échantillonnés appartenant à 25 espèces, dont 11
espèces de requins et 14 espèces de batoïdes. Aucune chimère n‘a été enregistrée. Les requins
échantillonnés étaient constitués majoritairement des espèces: Centrophorus granulosus, Galeus
melastomus, Squalus blainville et Mustelus mustelus. La majorité des batoïdes était constituée de
Rhinobatos rhinobatos, Rhinobatos cemiculus, Torpedo marmorata, Torpedo nobiliana, Raja
miraletus et Raja clavata. Les différents spécimens de poissons cartilagineux ont été pêchés à
des profondeurs allant de 10 à 600 m, en majorité à l‘aide de palangres, suivis des trémails puis
des filets maillants. La Capture par Unité d‘Effort a été employée en tant qu‘indice d‘abondance
et ses variations spatiales et saisonnières ont été analysées. La diversité spatio-temporelle a aussi
été estimée et les plus fortes valeurs ont été observées dans la région du sud et durant le
printemps et l‘hiver. Dans une seconde partie, différentes relations longueur-poids ont été établies
pour les espèces majoritaires présentant un nombre d‘individus supérieur à 10 (3 requins et 5
batoïdes).
Enfin, un focus a été porté sur la biologie et l‘écologie de deux espèces commercialement
importantes et bien exploitées dans les eaux côtières libanaises. La biologie des populations du
batoïde Rhinobatos rhinobatos (chapitre V) et du requin Centrophorus granulosus (chapitre VI) a été
évaluée séparément à partir d‘individus issus des deux sources de données combinées (scientifiques
et commerciales). Pour finir, le dernier chapitre (chapitre VII) est consacré à la discussion générale et
aux perspectives de cette étude.
Mots clés: Chondrichthyens; conservation; distribution; traits d‘histoire de vie; Liban; Bassin
Levantin
Table of contents

Table of contents
Chapter I: General Introduction ...................................................................................................... 1
1. Overview ................................................................................................................................. 1
2. The Mediterranean Sea: Biodiversity, threats and fisheries ................................................... 1
2.1. Geographical overview .................................................................................................... 1
2.2. Biodiversity ...................................................................................................................... 2
2.3. Threats .............................................................................................................................. 3
2.4. Fisheries ........................................................................................................................... 5
3. Chondrichthyans: Status, fisheries and threats ....................................................................... 7
3.1. Worldwide overview ........................................................................................................ 7
3.2. Chondrichthyan life history traits ................................................................................... 11
3.3. Mediterranean chondrichthyans ..................................................................................... 12
3.4. Mediterranean chondrichthyan fisheries and threats ...................................................... 14
3.5. Various management tools for coastal ecosystems ........................................................ 17
3.6. Eastern Mediterranean chondrichthyans ........................................................................ 19
4. Objectives of the study.......................................................................................................... 21
Chapter II: Material and Methods ................................................................................................. 23
1. Characteristics of the study area ........................................................................................... 23
1.1. Overview of the region ................................................................................................... 23
1.2. The Lebanese coast ........................................................................................................ 24
1.3. Currents and bathymetry ................................................................................................ 26
1.4. The fishery sector ........................................................................................................... 27
2. Data collection ...................................................................................................................... 29
2.1. CIHEAM PESCA-Libano .............................................................................................. 29
2.2. Fishermen ....................................................................................................................... 31