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ISRA FACTSHEETS

MEDITERRANEAN AND BLACK SEAS REGION

ISRA FACTSHEETS

MEDITERRANEAN AND BLACK SEAS REGION

Sigacik Bay ISRA

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Sigacik Bay ISRA

Sigacik Bay

Summary

Sigacik Bay is located in the southern Aegean Sea of Türkiye. The area has a narrow continental shelf and is characterised by sandy and muddy substrates. It overlaps with an Ecologically or Biologically Significant Marine Area (Central Aegean Sea) and with two Key Biodiversity Areas. Within the area there are: threatened species (Velvet Belly Lanternshark Etmopterus spinax); and reproductive areas (e.g., Blackmouth Catshark Galeus melastomus).

Sigacik Bay

DESCRIPTION OF HABITAT

Sigacik Bay is located in the southern Aegean Sea of Türkiye. The area extends from Doğanbey to Teke. The area has a narrow continental shelf and is characterised by sandy and muddy substrates (Soykan et al. 2016). The highest sea surface temperatures occur in the boreal summer (23.9°C) and the lowest in winter (16.5°C; Soykan et al. 2016).

The area overlaps with an Ecologically or Biologically Significant Marine Area, the Central Aegean Sea (CBD 2023), and with two Key Biodiversity Areas, Kizildag Izmir and Alaçatı (KBA 2023a, 2023b).

This Important Shark and Ray Area is benthic and is delineated from 100 m to a depth of 600 m, based on the distribution of the Qualifying Species in the area.

CRITERION A

VULNERABILITY

One Qualifying Species within the area is considered threatened with extinction according to the IUCN Red List of Threatened SpeciesTM. The Velvet Belly Lanternshark is assessed as Vulnerable (Finucci et al. 2021).

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Sigacik Bay is an important reproductive area for three shark species.

Between 2008–2009 and 2014, 129 Velvet Belly Lanternsharks were recorded from benthic trawlers (Eronat & Özaydın 2014; Bengil et al. 2019). Most individuals had sizes below size-at-maturity, and some were considered neonates based on their size (<10 cm total length [TL]), similar to the reported size-at-birth for the species (8–14 cm TL; Ebert et al. 2021). Previously, from 119 individuals collected in 2003–2004 between 200–500 m depths, all were juveniles (<21 cm TL) and some individuals were <14 cm TL (Bilge et al. 2010), confirming the regular presence of neonates in the area. Adults have rarely been reported as bycatch in benthic trawlers within the area (average size = 17.1 ± 0.4 cm TL; Eronat & Özaydın 2014; Bengil et al. 2019).

Between 2008–2009 and 2014, 441 Blackmouth Catsharks were collected from benthic trawlers (Eronat & Özaydın 2014; Bengil et al. 2019). Most individuals had sizes (<45 cm TL) below size-at-maturity (males 34–42 cm TL, females 39–45 cm TL; Ebert et al. 2021) and very few had larger sizes (average size = 14.6 ± 0.3 cm TL). Size-at-birth is unknown for this species, but some individuals sampled measured between 8.9–15 cm TL, which is smaller than the reported size-at-birth for related species, suggesting these were neonates (<20 cm TL for Corrigan’s Catshark Galeus corriganae; <17 cm TL for Gecko Catshark Galeus eastmani; Ebert et al. 2021).

Between 2008–2009 and 2014, 308 Longnose Spurdogs were recorded from benthic trawlers (Eronat & Özaydın 2014; Bengil et al. 2019). Some of the individuals are considered neonates based on their size (16–18 cm TL), which is similar to the reported size-at-birth for the species (~23 cm TL; Ebert et al. 2021). This species has been assessed as Data Deficient on the IUCN Red List and therefore, while data are limited, the lack of information means that these observations are important.

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