Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)

The Eastern Aegean Sea hosts a diverse assemblage of elasmobranchs, many of which are vulnerable or endangered. This study presents a fishery-independent assessment of species composition, catch characteristics, and spatial patterns in bottom trawl fisheries between Lesvos Island and Ayvalik. A tota...

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Main Authors: İlker Aydin, Alexandros Theocharis, Sercan Yapici, Dimitris Klaoudatos
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Oceans
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Online Access:https://www.mdpi.com/2673-1924/6/2/34
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author İlker Aydin
Alexandros Theocharis
Sercan Yapici
Dimitris Klaoudatos
author_facet İlker Aydin
Alexandros Theocharis
Sercan Yapici
Dimitris Klaoudatos
author_sort İlker Aydin
collection DOAJ
description The Eastern Aegean Sea hosts a diverse assemblage of elasmobranchs, many of which are vulnerable or endangered. This study presents a fishery-independent assessment of species composition, catch characteristics, and spatial patterns in bottom trawl fisheries between Lesvos Island and Ayvalik. A total of 48 surveys were conducted between September 2022 and October 2024, identifying nine elasmobranch species, with <i>Scyliorhinus canicula</i> (small-spotted catshark) and <i>Mustelus mustelus</i> (common smooth-hound) dominating the catch. Biological parameters, sex ratios, and condition upon capture and release were recorded, while catch per unit effort (CPUE) and diversity indices were used to evaluate temporal patterns. The survival probability was negatively affected by the trawl duration and elevated temperatures, emphasizing the need for mitigation measures. Spatial models revealed high-density zones that likely function as foraging or nursery grounds. Seasonal shifts in community composition were also evident. Many non-commercial species were discarded irrespective of their size or condition. These findings underscore the ecological importance of this understudied region and support the need for spatially explicit, species-specific management strategies, including gear selectivity improvements, seasonal closures, and Electronic Monitoring. The study offers a critical baseline for enhancing the sustainability of elasmobranch populations in the Eastern Mediterranean.
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spelling doaj-art-caef8991bc874692b6f5ccab3f925a2d2025-08-20T02:21:46ZengMDPI AGOceans2673-19242025-06-01623410.3390/oceans6020034Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)İlker Aydin0Alexandros Theocharis1Sercan Yapici2Dimitris Klaoudatos3Department of Fishing Technology, Faculty of Fisheries, Ege University, 35100 İzmir, TürkiyeDepartment of Ichthyology and Aquatic Environment, University of Thessaly, Fytokou Street, 38 446 Volos, GreeceFaculty of Fisheries, Muğla Sıtkı Koçman University, 48000 Muğla, TürkiyeDepartment of Ichthyology and Aquatic Environment, University of Thessaly, Fytokou Street, 38 446 Volos, GreeceThe Eastern Aegean Sea hosts a diverse assemblage of elasmobranchs, many of which are vulnerable or endangered. This study presents a fishery-independent assessment of species composition, catch characteristics, and spatial patterns in bottom trawl fisheries between Lesvos Island and Ayvalik. A total of 48 surveys were conducted between September 2022 and October 2024, identifying nine elasmobranch species, with <i>Scyliorhinus canicula</i> (small-spotted catshark) and <i>Mustelus mustelus</i> (common smooth-hound) dominating the catch. Biological parameters, sex ratios, and condition upon capture and release were recorded, while catch per unit effort (CPUE) and diversity indices were used to evaluate temporal patterns. The survival probability was negatively affected by the trawl duration and elevated temperatures, emphasizing the need for mitigation measures. Spatial models revealed high-density zones that likely function as foraging or nursery grounds. Seasonal shifts in community composition were also evident. Many non-commercial species were discarded irrespective of their size or condition. These findings underscore the ecological importance of this understudied region and support the need for spatially explicit, species-specific management strategies, including gear selectivity improvements, seasonal closures, and Electronic Monitoring. The study offers a critical baseline for enhancing the sustainability of elasmobranch populations in the Eastern Mediterranean.https://www.mdpi.com/2673-1924/6/2/34fisheries management<i>Mustelus mustelus</i><i>Scyliorhinus canicula</i>bycatchdiversity indicesCPUE
spellingShingle İlker Aydin
Alexandros Theocharis
Sercan Yapici
Dimitris Klaoudatos
Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)
Oceans
fisheries management
<i>Mustelus mustelus</i>
<i>Scyliorhinus canicula</i>
bycatch
diversity indices
CPUE
title Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)
title_full Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)
title_fullStr Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)
title_full_unstemmed Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)
title_short Elasmobranch Species Composition in Otter Trawl Fisheries (Eastern Aegean Sea)
title_sort elasmobranch species composition in otter trawl fisheries eastern aegean sea
topic fisheries management
<i>Mustelus mustelus</i>
<i>Scyliorhinus canicula</i>
bycatch
diversity indices
CPUE
url https://www.mdpi.com/2673-1924/6/2/34
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