Based on the latest IUCN assessment, about 50% of the sharks and rays populations in the Mediterranean are faced with extinction (Dulvy et al., 2016). More specifically, the Mediterranean species populations of Squatina aculeata, Squatina oculata, Squatina squatina, Glaucostegus cemiculus and Gymnura altavela are listed as Critically Endangered and that of Rhinobatos rhinobatos as Endangered according to the IUCN Red List of Threatened Species (IUCN, 2019). All these species are suffering local extinctions, owing to a severe conflict with fisheries, mostly being caught as bycatch (Dulvy et al., 2016). Little information about their population is known in the Mediterranean and in general, while data are scarce either due to the misreported data or the unavailable non-fisheries dependent information.
The main goals focus on understanding more about the population, the relative abundance, the activity patterns and the home range of guitarfish (Rhinobatos rhinobatos and Glaucostegus cemiculus) and Gymnura altavela in selected areas of Kos Island, by collecting both quantitative and qualitative seasonal data and information about the current and past presence of angel sharks (Squatina aculeata, Squatina oculate, Squatina squatina) around Kos Island, utilizing the local ecological knowledge of marine users.
This project will allow us to collect the first non-fisheries dependent data in Greece from highly threatened elasmobranch species, investigate a potentially critical area for the selected species, and learn more about their biology and ecology. It will also provide us with the baseline knowledge that will help us to develop an adequate management plan for the species populations in the area. In addition, the data will feed the efforts for the Sub Regional Action Plan for the Conservation of Angel Sharks in the Eastern Mediterranean and the Global Action Plan for the Conservation of Rhino Rays and other relevant projects.
Underwater Visual Census (UVC) and Baited Remote Underwater Video Systems (BRUVS) will be used for monitoring guitarfish and Gymnura altavela in selected areas around Kos. Surveys will take place on a seasonal basis· in total, 4 UVC and 8 BRUVS surveys. For utilizing Local Ecological Knowledge (LEK) of marine users in Kos, at least 50 questionnaires will be developed. Surveys will be conducted amongst marine users of the island and information about the presence of the selected species will be collected.
Spiny butterfly rays
The spiny butterfly ray Gymnura altavela is a ray species that has a patchy distribution in tropical and subtropical areas. It is a coastal species that often inhabits brackish waters. The species population is Critically endangered, and it is protected by the recommendation of GFCM/42/2018/2 (amending GFCM/36/2012/3).
The guitarfishes Rhinobatidae is a family of rays that is found in subtropical areas and in the Mediterranean Sea. More specifically the species Rhinobatos rhinobatos and Glaucostegus cemiculus are extant in Greek waters but are considered rare and their population has been listed as Endangered. The species is protected by the recommendation of GFCM/42/2018/2 (amending GFCM/36/2012/3).
Angel sharks Squatinidae is a family of sharks with flattened bodies and broad pectoral fins that are extant in broad geographical range but are found in small areas mostly due to their characteristics. More specifically the species Squatina aculeata, Squatina oculate and Squatina squatina are extant in Greek waters but are found rarely and their population is listed as Critically endangered. The species are protected by the recommendation of GFCM/42/2018/2 (amending GFCM/36/2012/3).
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