Otoliths are used in taxonomy and ichthyology as they can provide a wide range of information about specimens. They are an essential tool to monitor the most sensitive species for a sustainable exploitation level. Despite the increasing use of sagittae in research, their inter- and intra-specific variability and eco-functionality are still poorly explored. This paper aims to investigate the inter- and intra-specific variability of Mugilidae sagittae using morphological and morphometrical analysis, as well as scanning electron microscopy and shape analysis. The sagittae of 74 specimens belonging to three different Mugilidae species, collected from a coastal lagoon, were analyzed to give an accurate description of their morphology, morphometry, shape and crystalline habits. The results highlighted the intra- and inter-specific variability of sagittae, showing morphometrical differences among species and slight differences between left and right sagittae in C. labrosus individuals. Moreover, SEM images showed a peculiar crystal organization, with several different crystal habits and polymorphs. This study provides an accurate description of sagittae in the studied species, deepening the knowledge on inter- and intra-specific variations and crystal habits and providing data which will be useful for future studies on otoliths. With this data, it will be possible to improve conservation and exploitation sustainability in sensitive habitats.

Essential oils (EOs) are natural compounds used in various fields such as traditional medicine, gastronomy, and agriculture, often used against plant and animal parasites. In the present study, the toxic and pathological effects of basil (Ocimum basilicum) essential oil on the development of zebrafish embryos was investigated. The manufacturer datasheet reported linalool and eugenol as major compounds. The effects of the essential oil were evaluated through a zebrafish embryo toxicity test (ZFET) following the OECD n°236 guidelines. Embryos were exposed to different essential oil concentrations (50, 100, and 200 μL/L). Results showed mortality effects in the experimental groups in a dose-dependent manner. Moreover, zebrafish exposed to the higher concentration showed several pathological alterations; particularly, delayed hatching, pericardial edema, and a significant reduction of heart rate after 96 h post-fertilization (hpf) compared to the control group. Results reported here suggest an anaesthetic effect of the O. basilicum at low concentrations, due to the possible synergist effect of the main components such as linalool and eugenol which act on the GABAergic system evoking bradycardia.

This study represents the first assessment of plastic waste within Posidonia spheroids on four sandy, Mediterranean beaches, each characterized by varying levels of anthropogenic influence. Fifty-five (68.7%) spheroids, out of eighty examined, included plastic litter. A total of 202 plastic items were isolated. Plastic abundance was 2.5 items/spheroid corresponding to 132 items per kilogram. The length of plastic items ranged from 0.1 to 50 mm. Fibers, tangled fibers and fragments were the most common shapes. The spheroids exhibited a substantial capacity for trapping plastic waste, with notable differences among the beaches. Our results underscore the significance of implementing a beach clean-up plan aimed at removing all spheroids to prevent them from disintegrating and releasing trapped plastic waste into the environment. Manual removal is recommended to safeguard the beaches, and this process should target all spheroids, regardless of their size. This study provides valuable insights that can inform marine litter monitoring programs, contribute to the development of tailored management measures, and support the implementation of specific action plans to mitigate Mediterranean microplastic pollution.

This study evaluates for the first time the plastic litter occurrence in Posidonia spheroids of four Mediterranean sandy beaches at different anthropogenic impact. A total of 80 spheroids was analyzed and 202 plastic items were found. Spheroids entangled a high number of plastic litter (132 plastic items/kg) with significant differences between beaches. Our results highlight the importance to implement the beach cleaning plan for the removal of all spheroids in order to prevent them from flaking and releasing the marine litter trapped inside them again in the environment. Spheroids should be manually removed in order to protect the banquettes. The removal should be involved all spheroids, independently from their size. This study adds data for the implementation of the monitoring program of marine litter and contributes to the development of specific management measures as well as implement Mediterranean action plans.

Mullets (Osteichthyes: Mugilidae) are a euryhaline species widely distributed all over the world, thus representing an excellent study model for host–parasite interactions. From March to June 2022, 150 mullets, belonging to Chelon labrosus (n = 99), Chelon auratus (n = 37), and Oedalechilus labeo (n = 14) species, were caught to identify the helminth parasite fauna of the different mullet species present in the Ganzirri Lagoon (Messina, Sicily, Italy). A parasitological evaluation of the gastrointestinal tract (GIT) was carried out with a total worm count technique (TWC) to detect helminth presence. All collected parasites were stored in 70% ethanol until morphological evaluation, and frozen at −80 °C for subsequent molecular analysis, using 28S, ITS-2, 18S primers. The morphological evaluation allowed for the identification Acanthocephalan parasites (Neoechinorhynchus agilis) from two C. labrosus specimens. Sixty-six samples were positive for adult digenean trematodes (C. labrosus, 49.5 %; C. auratus, 27%, and O. labeo, 50%), molecularly identified as Haploporus benedeni. This study represents the first survey of helminthic parasite fauna of mullets from the south of Italy. The presence of Hydrobia sp. in the stomach contents of mullets allowed us to infer the H. benedeni life cycle in the Ganzirri lagoon.