Identification guide to the deep-sea cartilaginous fishes of the Indian Ocean

This guide was prepared under the “FAO Deep–sea Fisheries Programme”, thanks to a generous funding from the Governments of Norway and Japan (Support to the implementation of the International Guidelines on the Management of Deep-Sea Fisheries in the High Seas and Fisheries management and marine conservation within a changing ecosystem context projects) for the purpose of assisting states, institutions, the fishing industry and RFMO/As in the implementation of FAO International Guidelines for the Management of Deep-sea Fisheries in the High Seas. It was developed in close collaboration with the FishFinder Programme of the Marine and Inland Fisheries Branch, Fisheries Department, Food and Agriculture Organization of the United Nations (FAO). Its production is the result of a collaborative effort among scientists, fishery observers and the fishing industry who attended the FAO regional workshop held in Flic en Flac, Mauritius, from January 16 to 18, 2013. The general objective of the workshop was to discuss, share experiences and finally draft recommendations for the development of field products aimed at facilitating the identification of Indian Ocean deep-sea cartilaginous fishes. The present guide covers the deep–sea Indian Ocean, primarily FAO Fishing Areas 51 and 57, and that part of Area 47 that extends from Cape Point, South Africa to the east, e.g. the extreme southwestern Indian Ocean. It includes a selection of species of major, moderate and minor importance to fisheries as well as those of doubtful or potential use to fisheries. It also covers those little known species that may be of research, educational, and ecological importance. The Indian Ocean deep–sea chondrichthyan fauna is currently represented by 117 shark, 61 batoid and 17 chimaera species. This guide includes full species accounts for 36 shark species selected as being the more difficult to identify and/or commonly caught. Each species is described, depicted with a colour illustration and photo, and key distinguishing features of similar–looking species occurring in the same area are highlighted allowing for easy and accurate identification in the field. An additional 16 shark species, that have very particular characteristics and/or are rarely caught, are displayed with a simplified account that includes a line drawing and other information useful for their correct identification. Finally, short accounts of 52 shark species that could be misidentified with more common species occurring in the area are also included. The batoids, as the information available on the species being caught in the Indian Ocean is scanty and in order to avoid confusion among users, are dealt with at the family level, whereas the chimaeras at the genus level. Therefore, in order to improve knowledge on the latter groups it is recommended that the caught specimens be preserved for further investigation following the instructions here included. This guide is intended to help fishery workers collecting catch data in the field in the identification of the cartilaginous fish species they might encounter. It is conceived to be updatable, offering the possibility to add new species accounts as new species are described.