Biological and ecological processes during the establishment of a marine invasion: the Siganus rabbitfishes from the Red Sea to the coastal areas of Cyrenaica, Libya Abdulghani A. Hamad Abdulghani This thesis is presented to the School of Environment and Life Sciences, University of Salford, in fulfilment of the requirements for the degree of Ph.D Supervisors: Prof. Stefano Mariani and Dr. Chiara Benvenuto University of Salford. November, 2017 Table of Contents List of figures ............................................................................................................................ V List of tables .......................................................................................................................... VIII Acknowledgments...................................................................................................................... 1 Declaration ................................................................................................................................. 2 Chapter I..................................................................................................................................... 3 Abstract ..................................................................................................................................... 4 Introduction ................................................................................................................................ 5 1.1 Biological invasions ............................................................................................................. 5 1.1.1 Biological invasions: definitions....................................................................................... 5 1.1.2. Biological invasions: implications ........................................................................... 6 1.1.3. Ecological consequences of invasions ...................................................................... 7 1.1.4. Evolutionary consequences of invasions .................................................................. 9 1.1.5. Mediterranean biodiversity ..................................................................................... 11 1.1.6. Biological invasions in the Mediterranean Sea ...................................................... 13 1.1.7. Biology and behaviour of invasive fish species ..................................................... 17 1.2. Siganidae ....................................................................................................................... 18 1.2.1. Siganus luridus (Dusky spinefoot) ......................................................................... 19 1.2.2. Siganus rivulatus (Marbled spinefoot) ................................................................... 20 1.2.3. Implication of Siganus species invasions ............................................................... 21 1.3. Aims of the study .......................................................................................................... 23 1.3.1. Shape variation in sympatric S. luridus and S. rivulatus, in relation to their novel and native habitats ............................................................................................................ 23 1.3.2. Trophic level and niche overlap of S. luridus and S. rivulatus in native and novel habitats .............................................................................................................................. 23 1.3.3. Comparative phylogeography of the Lessepsian invaders: S. luridus and S. rivulatus ............................................................................................................................ 24 1.4. Study areas and sampling design .................................................................................. 24 1.4.1. Native area of distribution of Siganus .................................................................... 24 1.4.2. Invaded area of Siganus along the Libyan coast .................................................... 24 1.4.3 Cyrenaica coast ........................................................................................................ 26 1.4.4. Sampling design ..................................................................................................... 29 Chapter II ................................................................................................................................. 32 I Comparison of shape variation in sympatric Siganus luridus and S. rivulatus, in the Egyptian and Cyrenaican coast using geometric morphometrics ..................................... 33 Abstract ................................................................................................................................... 33 2.1. Introduction ....................................................................................................................... 34 2.2. Aims .............................................................................................................................. 36 2.3. Materials and methods .................................................................................................. 37 2.3.1. Fieldwork ................................................................................................................ 37 2.3.2. Length-weight relationships ................................................................................... 37 2.3.3 Geometric morphometrics ....................................................................................... 37 2.3.4 Colouration measurements ...................................................................................... 40 2.4. Results ........................................................................................................................... 41 2.4.1. Length-weight relationships ................................................................................... 41 2.4.2. Geometric morphometrics ...................................................................................... 46 2.4.2.1. Relative Warp Analysis (RWA) .......................................................................... 47 2.4.1.2. Principal component analysis (PCA) ................................................................... 51 2.4.3. Colouration ............................................................................................................. 58 2.5. Discussion ..................................................................................................................... 63 2.5.1. Length-weight relationships ................................................................................... 63 2.5.2. Geometric morphometrics ...................................................................................... 64 2.5.3. Colouration ............................................................................................................. 66 Chapter III ................................................................................................................................ 68 Trophic level and niche overlap of S. luridus and S. rivulatus in native and novel habitats .................................................................................................................................... 69 Abstract ................................................................................................................................... 69 3.1. Introduction ................................................................................................................... 70 3.2. Stable Isotope Analysis (SIA) ....................................................................................... 71 3.2.1. Isotopic Dietary Models ............................................................................................. 72 3.2.2. Carbon ........................................................................................................................ 72 3.2.3. Nitrogen ...................................................................................................................... 73 3.2.4. Stable isotope analysis for invasive species ............................................................... 73 3.3. Aims .............................................................................................................................. 81 3.4. Material and methods .................................................................................................... 82 3.4.1. Samples collections .................................................................................................... 82 3.4.2. Carbon and Nitrogen Methodology............................................................................ 83 II 3.4.3. Isotope analyses.......................................................................................................... 83 3.5. Results ........................................................................................................................... 84 3.6. Discussion ..................................................................................................................... 96 Chapter IV ................................................................................................................................ 99 Comparative phylogeography of the Lessepsian invaders: S. luridus and S. rivulatus .............................................................................................................................................. 1000 Abstract ..............................................................................................................................