The monk seal is the most endangered pinniped worldwide and the only one found in the Mediterranean, where its distribution and abundance have suffered a drastic decline in the last few decades. The limited understanding of the population demographics and conservation status of this species are due to both its rarity and evasiveness, with records biased towards occasional, mostly coastal, encounters. Current molecular techniques allow us to detect DNA traces released into the environment (eDNA) by any organism. We have developed three species-specific qPCR-assays targeting the 12S/16S rRNA mitogenome regions of the monk seal. The assays have been tested extensively on a comprehensive and diverse set of samples (n = 73), including positive controls from a breeding population in Madeira collected during their peak abundance, and two opportunistic collections of Mediterranean eDNA samples (offshore/coastal) from on-going projects. Monk seal DNA was detected in 47.2% of the samples collected from a ferry platform in the Tyrrhenian (2018–2019) and in 66.7% of those obtained in the Pelagie archipelago in the Strait of Sicily (2020). These findings anticipated subsequent visual observations in the proximity of these sampling areas by up to 2 years. At the Tyrrhenian site, monk seal detection increased between 2018 and 2019. The demonstrated approach provides a non-invasive and highly sensitive tool for defining the monk seal actual distribution and home range -enabling monitoring also in nocturnal hours-, for assessing its recovery rate and pinpointing coastal/offshore sites where prioritizing conservation, research, citizen-science, and educational opportunities.

The monk seal is the most endangered pinniped worldwide and the only one found in the Mediterranean, where its distribution and abundance have suffered a drastic decline in the last few decades. Data on its status are scattered due to both its rarity and evasiveness, and records are biased towards occasional, mostly coastal, encounters. Nowadays molecular techniques allow us to detect and quantify minute amounts of DNA traces released in the environment (eDNA) by any organism. We present three qPCR-assays targeting the monk seal mitogenome. The assays were soundly tested on an extensive and diversified sample set (n=73), including positive controls from Madeira breeding population collected during the peak of abundance, and two opportunistic Mediterranean eDNA-sample collections (offshore/coastal) from on-going projects. Monk seal DNA was detected in 47.2% and 66.7% of the samples collected in the Tyrrhenian from a ferry platform (2018-2019) and in the Pelagie archipelago -Strait of Sicily- (2020) respectively, anticipating (up to 2 year) visual observations occurred subsequently in proximity of the sampled areas. In the Tyrrhenian, detection occurrence increased between 2018 and 2019. Monk seal DNA recoveries were commoner in night-time ferry-samples, suggesting nocturnal predatory activity in pelagic waters. The proposed technique provides a non-invasive and yet highly-sensitive tool for defining the monk seal actual distribution and home range, its recovery rate and pinpoint coastal/offshore localities where prioritizing conservation, research, citizen science and education initiatives.

Verified records of the bull shark Carcharhinus leucas are lacking in the Maldives. This study provides the first confirmed evidence of 23 sightings observed from 2013 to 2023 in the central and southern atolls of this archipelago. Most of the sightings occurred in close proximity of inhabited areas, where food waste is often discarded into the water, or in several dive sites, suggesting the presence of this species in different location around Central and Southern Atolls. Although further research is required to fully investigate the C. leucas population in the Maldives, this report documents and confirms its presence in this region.This article is protected by copyright. All rights reserved.

The monk seal, the most endangered pinniped worldwide and the only one found in the Mediterranean, has suffered a drastic decline in the last few decades. Nowadays molecular techniques allow to detect minute amounts of DNA released in the environment (eDNA) by any organism. We present three qPCR-assays targeting the monk seal mitogenome. The assays were soundly tested on an extensive/diversified sample set (n=73), including positive controls from Madeira breeding population and two opportunistic Mediterranean eDNA-sample collections (offshore/coastal) from on-going projects. Monk seal DNA was detected in 47.2% and 66.7% of the samples collected in the Tyrrhenian from a ferry platform (2018-2019) and in the Pelagie archipelago (2020) respectively, anticipating (up to 2 year) visual observations occurred subsequently in proximity of the sampled areas. In the Tyrrhenian, detection occurrence increased between 2018 and 2019. Monk seal DNA recoveries were commoner in night-time ferry-samples, suggesting nocturnal predatory activity in pelagic waters. The proposed technique provides a non-invasive and yet highly-sensitive tool for defining the monk seal actual range, its recovery rate and pinpoint coastal/offshore localities where prioritizing conservation.