The Atlantic pearl oyster, Pinctada radiata (Leach, 1814), is an Indo-Pacific bivalve of the subtidal zone that has colonized habitats all over the Mediterranean. There is a lack of detailed information on the reproductive activity of P. radiata in Hellenic waters, especially following the recent amendment of national legislation aiming to regulate the fishery and prevent illegal fishing and trafficking as a substitute for indigenous oysters. A total of 703 individuals were collected by scuba diving from the southwest part of Evia Island. Gonad microscopic examination indicated that gametogenesis occurs from February to September, with a recovery stage in early autumn. Synchronicity occurs for both sexes, with temperature being the main controlling factor. The annual recruitment pattern indicated two prominent peaks of similar magnitude. Analysis of covariance indicated a significant temperature effect on gonad index above 22 degrees. Onset of sexual maturity (L₅₀) was estimated at 47.2 mm in shell height and 27.09 gr in total weight for the entire population. The sex ratio was in favor of females at 1:1.70, with 7% and 19% of the individuals assessed macroscopically and microscopically identified as hermaphrodites, respectively. Results offer valuable information for the management and conservation of pearl oyster populations.

The Atlantic pearl oyster Pinctada radiata (Leach, 1814), the first documented Lessepsian bivalve species to enter the Mediterranean basin, is present in various coastal areas in Greece, and constitutes, almost exclusively, a domestic commercial bivalve resource. The present study aimed to contribute to the limited information available on P. radiata population structure and dynamics in Hellenic waters, especially following the recent enforcement of legislation for regulation of its fishery. A total of 703 individuals were collected using scuba diving from the South Evoikos Gulf. The male-to-female ratio (1:1.70) significantly departed from 1:1. A higher probability for female prevalence was exhibited for shell heights over 50.77 mm. Significant differences were exhibited in the shell height–total weight relationship between the sexes. The fourth-year class was the dominant cohort, comprising 50.09% of the population, out of the seven age classes identified. Asymptotic length was estimated at 109.1 mm and growth index at 3.35, respectively. Longevity was estimated at 15.7 years, with natural mortality (M) at 0.39 and total mortality (Z) at 0.76. The probability of capture (LC₅₀) was estimated at 50.72 mm at 2.8 years. Biological reference points F_MSY and E_MSY were higher than the fishing mortality and current exploitation rate, respectively, indicating the potential for further population exploitation.

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SCIEPublish is an international open-access journal publishing service provider run by SCIE Publishing Limited, dedicated to supporting and inspiring scientists or institutions/societies who aspire to publish high-quality journals.

In the Mediterranean, the bluespotted cornetfish Fistularia commersonii Rüppell, 1838, presents a minor socioeconomic impact and the assessment of any environmental impact requires more relevant data. The congeneric red cornetfish Fistularia petimba Lacepède, 1803, has expanded its distribution range within the basin but only small numbers have been reported to date. A total of 207 individuals of F. commersonii were collected between April 2021 and March 2022 from the Levantine coast of Rhodes and 92 more from various locations. Additionally, 13 individuals of Fistularia petimba were caught in March 2024 from the Aegean coasts of the island. We aim to assess the current progression of the population of the two cornetfish, the possible further exploitation of F. commersonii to boost the local fishing economy, their possible dietary overlaps and to add valuable biological and ecological data. In F. commersonii, male to female ratio (1:1.33) significantly departed from 1:1, with length–weight relationships exhibiting positive allometric growth. Six age groups were identified. The highest reproductive intensity was observed during summer. The onset of sexual maturity was estimated at 65.52 cm in total length (1.8 years). Longevity was estimated at 11.1 years with females growing larger than males. The exploitation rate (E = 0.47) indicated that the population is underexploited. The optimum and target fishing mortality were higher in comparison with the present fishing mortality (F = 0.48), indicating a potential for commercial exploitation of the species. For F. petimba, the sex ratio was 1:2.25. The species preys on crustaceans, followed by fish and molluscs. The finding of Vanderhorstia mertensi (Klausewitz, 1974) in the stomach content of both cornetfishes constitutes the second published record for Hellenic waters and the first for the Dodecanese Islands.

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