........................................................................................................................................... ix RESUMO ................................................................................................................................................ xi RÉSUMÉ ................................................................................................................................................. xiii ACKNOWLEDGEMENTS ................................................................................................................... xv CHAPTER 1 – GENERAL INTRODUCTION AND AIMS ............................................................... 17 The Blackspot Seabream, Pagellus bogaraveo ....................................................................... 19 Distribution, ecology and reproduction ........................................................................ 19 Vulnerability to fishing pressure .................................................................................. 20 Current state of fisheries in the north-east Atlantic ...................................................... 20 Aquaculture production ................................................................................................ 21 The Study of Fish Stocks: Biology meets Fisheries ................................................................ 22 Identification methods and the stock concept ............................................................... 22 Parasites as biological tags ........................................................................................... 23 Population Structure of Pagellus bogaraveo ........................................................................... 25 Lack of differentiaion between Atlantic and Mediterranean populations .................... 25 Population structure in the north-east Atlantic ............................................................. 26 Main Aims of This Study .......................................................................................................... 33 CHAPTER 2 – ECTOPARASITES ....................................................................................................... 35 Fish Ectoparasites ..................................................................................................................... 37 Ectoparasites of marine fish .......................................................................................... 37 Impact of ectoparasites on aquaculture ......................................................................... 37 Ectoparasites of Blackspot Seabream ...................................................................................... 38 Ectoparasite communities ............................................................................................. 38 Microhabitat distribution of Hatschekia pagellibogneravei on the gills ...................... 39 Hermida M., Cruz C., Saraiva A. (2012). Ectoparasites of the blackspot seabream Pagellus bogaraveo (Teleostei: Sparidae) from Portuguese waters of the north-east Atlantic. Journal of the Marine Biological Association of the United Kingdom, in press .......................... 45 Hermida M., Cruz C., Saraiva A. (2012). Distribution of Hatschekia pagellibogneravei (Copepoda: Hatschekiidae) on the gills of Pagellus bogaraveo (Teleostei: Sparidae) from Madeira, Portugal. Folia Parasitologica, 59: 148-152 .................................................................... 53 CHAPTER 3 – ENDOPARASITES ........................................................................................................ 59 Endoparasites of Marine Fish ................................................................................................... 61 Anisakid Nematodes ................................................................................................................... 61 Biology and ecology of anisakid nematodes ................................................................. 61 Identification of anisakid larvae parasitic in fish ........................................................... 62