A Non-Lethal Transillumination Method for Early Sex Identification in Juvenile Turbot (Scophthalmidae: <i>Scophthalmus maximus</i>)
AQUACULTURE RESEARCH, cilt.2026, sa.1, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 2026 Sayı: 1
- Basım Tarihi: 2026
- Doi Numarası: 10.1155/are/1020900
- Dergi Adı: AQUACULTURE RESEARCH
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, BIOSIS, CAB Abstracts, Environment Index, Geobase, Directory of Open Access Journals, Zoological Record, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Biomedical Reference Collection: Corporate Edition (EBSCO), Earth, Atmospheric, & Aquatic Science Collection (ProQuest)
- Karadeniz Teknik Üniversitesi Adresli: Evet
Özet
Aquaculture profitability in turbot (Scophthalmus maximus) is strongly influenced by sex-specific growth, as females generally outperform males under culture conditions and therefore may provide greater production efficiency. This study evaluated dry-chamber transillumination as a rapid, low-cost, and non-lethal method for early sex identification in juvenile turbot. Thirty-nine hatchery-produced juveniles from two family groups, ranging from 16.3 to 26.6 cm in total length and from 58.5 to 268.0 g in body weight, were examined on a transparent acrylic surface using light transmitted from below by a bottom-mounted 150 W daylight lamp while fish were viewed from the dorsal side. Sex was assigned using five predefined visual criteria: gonadal size, shape and longitudinal elongation, contrast, pigmentation or darkened silhouette and posterior extension within the body cavity. Classifications were validated by gonad weighing and microscopic sex confirmation. Microscopy identified 19 females and 20 males. Under transmitted light, females showed an elongated gonadal silhouette extending posteriorly within the body cavity, whereas males showed smaller, less distinct gonadal tissue mainly restricted to the anterior abdominal region. All transillumination-based classifications matched microscopic sex confirmation, yielding 100% observed agreement under the tested conditions (n = 39; exact binomial 95% CI: 91.0%-100%). The lowest successfully classified fish weighed 58.5 g, representing the lowest tested body weight in this study rather than a lower operational threshold. Within the examined size range, dry-chamber transillumination may support early sex-based management in juvenile turbot; however, broader validation across smaller body-weight classes, additional stocks, hatcheries, rearing conditions, and independent observers remains necessary.