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The study deals with aspects of the population dynamics in the thornback ray (<italic>Raja clavata</italic> L., 1758), one of the most abundant cartilaginous fish caught in the North Aegean Sea. Females accounted for 73.08% and males 26.92% of all individuals. Total length of females and males ranged between 50.2 and 89.9 cm (disc width: 33.4–62.0 cm), and between 43.1 cm and 82.7 cm (disc width: 30.7–64.2 cm), respectively. Relationships between total length (TL) and total weight (TW), and between disc width (DW) and total weight (TW) were described by the equations: TW = 0.0041 TL3.10 and TW = 0.0178 DW3.03, respectively. Age data derived from vertebrae readings were used to estimate growth parameters using the von Bertalanffy function: L∞ = 101.71 cm, K = 0.18 y−1, t0 = −0.07 y for males and L∞ = 106.54 cm, K = 0.16 y−1, t0 = −0.28 y for females. The maximum age was 8 years for males and females. Total length at first maturity of males and females was 70.9 cm and 81.2 cm, respectively. Based on the gonadosomatic index and gonadal macroscopic observations, it was determined that the spawning period lasted throughout the year. Stomach content analysis showed that crustaceans (53.03% IRI) and teleosts (14.70% IRI) were the most preferred prey.
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The study deals with aspects of the population dynamics in the thornback ray (Raja clavata L., 1758), one of the most abundant cartilaginous fish caught in the North Aegean Sea. Females accounted for 73.08% and males 26.92% of all individuals. Total length of females and males ranged between 50.2 and 89.9 cm (disc width: 33.4–62.0 cm), and between 43.1 cm and 82.7 cm (disc width: 30.7–64.2 cm), respectively. Relationships between total length (TL) and total weight (TW), and between disc width (DW) and total weight (TW) were described by the equations: TW = 0.0041 TL3.10 and TW = 0.0178 DW3.03, respectively. Age data derived from vertebrae readings were used to estimate growth parameters using the von Bertalanffy function: L∞ = 101.71 cm, K = 0.18 y−1, t0 = −0.07 y for males and L∞ = 106.54 cm, K = 0.16 y−1, t0 = −0.28 y for females. The maximum age was 8 years for males and females. Total length at first maturity of males and females was 70.9 cm and 81.2 cm, respectively. Based on the gonadosomatic index and gonadal macroscopic observations, it was determined that the spawning period lasted throughout the year. Stomach content analysis showed that crustaceans (53.03% IRI) and teleosts (14.70% IRI) were the most preferred prey.

Biology of the thornback ray (<italic>Raja clavata</italic> Linnaeus, 1758) in the North Aegean Sea

Graduate School of Natural and Applied Sciences, Department of Marine Science and Limnology

Marine Science and Technology Faculty, Department of Marine Science and Limnology

Oceanological and Hydrobiological Studies

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Biology of the thornback ray ( Linnaeus, 1758) in the North Aegean Sea

The study deals with aspects of the population dynamics in the thornback ray (Raja clavata L., 1758), one of the most abundant cartilaginous fish caught in the...

Biology of the thornback ray (Raja clavata Linnaeus, 1758) in the North Aegean Sea

Article Category: Original research paper

Publié en ligne: 05 juin 2021

Pages: 115 - 127

Reçu: 23 sept. 2020

Accepté: 01 déc. 2020

DOI: https://doi.org/10.2478/oandhs-2021-0011

Mots clés
age and growth, reproduction, feeding, North Aegean Sea

© 2021 Koray Cabbar et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Biology of the thornback ray (Raja clavata Linnaeus, 1758) in the North Aegean Sea

Article Category: Original research paper

Publié en ligne: 05 juin 2021

Pages: 115 - 127

Reçu: 23 sept. 2020

Accepté: 01 déc. 2020

DOI: https://doi.org/10.2478/oandhs-2021-0011

Mots clésage and growth, reproduction, feeding, North Aegean Sea

© 2021 Koray Cabbar et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Mots clés
age and growth, reproduction, feeding, North Aegean Sea