Search the repository

A+ | A- | | SLO | ENG

Abstract: The first record of the ribbon worm Notospermus annulatus (Grube, 1840) in Bosnia and Herzegovina is presented. For a long time, it was regarded as a synonym of Notospermus geniculatus (Delle Chiaje, 1822), but based on recent molecular phylogenetic study its status as a separate species is proposed and followed in this paper. A single specimen was recorded on 2nd October 2021 in a small bay near Opuće Village on Klek Peninsula. This finding contributes to the understanding of the species’ distribution in the Adriatic Sea and expands the knowledge of a scarcely known national marine fauna. This is also the first record of any Nemertea species in marine waters in Bosnia and Herzegovina.
Keywords: Adriatic Sea, Neum Bay, distribution, marine fauna, Mediterranean
Published in DiRROS: 31.07.2026; Views: 164; Downloads: 96
Full text (2,14 MB)
This document has many files! More...

Abstract: The authors report the capture of a specimen of driftfish, Cubiceps gracilis, from the Algerian coast. The present specimen was a female measuring 655 mm in total length (TL) and weighing 1580 g in total body weight. Its description includes some morphometric measurements and meristic counts. This is the first specimen of the species to have been captured in at least 50 years, confirming that it is a rare species in this area. C. gracilis is an oceanic epipelagic and mesopelagic species generally inhabiting deep bottoms, and is poorly exploited, due also to its low economic value.
Keywords: Cubiceps gracilis, Mediterranean Sea, distribution, habitat, description
Published in DiRROS: 31.07.2026; Views: 78; Downloads: 53
Full text (1,85 MB)
This document has many files! More...

Abstract: The recent first findings of the Lessepsian migrant Lutjanus argentimaculatus (Forsskål, 1775) and of the Atlantic range-expanding Psenes pellucidus Lütken, 1880 in the waters of Malta, central Mediterranean, are described. The current distribution in the basin of these two fish species is briefly discussed.
Keywords: Non-Indigenous species, Lessepsian migration, range-expanding species, Mediterranean Sea, citizen science
Published in DiRROS: 31.07.2026; Views: 113; Downloads: 71
Full text (1,79 MB)
This document has many files! More...

Abstract: Machine learning models provide a scalable approach for predicting the diversity of eukaryotic microbial plankton from environmental predictors. However, the extent to which these models generalize to data outside the training set remains poorly quantified. In this study, XGBoost was used to predict the 18S rRNA gene Shannon Diversity Index (SDI) from seven environmental predictors derived from satellite and model data. Surface samples were collected between 2001 and 2025 at two fixed stations in the northwestern Mediterranean (BBMO and SOLA), one fixed station in the northern Adriatic Sea (VIDA), and during the HOTMIX expedition, which sampled an east-west open-sea transect across the Mediterranean Sea. Model performance was assessed using standard repeated K-fold cross-validation (CV), Leave-One-Dataset-Out CV (LODO-CV), and a blocked spatiotemporal CV that combined LODO with temporal forward chaining. Under standard K-fold CV, the model showed moderate performance (R² = 0.44, RMSE = 0.59). In contrast, performance declined substantially under LODO-CV (R² = 0.09, RMSE = 0.73), with uniformly low per-dataset generalization, a pattern also observed with blocked spatiotemporal CV. VIDA and HOTMIX sampled environmental regimes distinct from those at BBMO and SOLA, which may partly explain their poor transferability. Additionally, BBMO and SOLA, despite similar environmental conditions, exhibited poor transferability, indicating that technical differences among independently collected 18S rRNA datasets likely constrain transferability, although their effects cannot be disentangled from environmental variation. Overall, these results highlight the limitations of imbalanced training data and underscore the importance of spatially explicit evaluation, protocol standardization, and environmentally representative coverage.
Keywords: cross-validation, data leakage, eukaryotic plankton, machine learning, marine biodiversity, Mediterranean Sea, omics, shannon diversity index
Published in DiRROS: 29.07.2026; Views: 157; Downloads: 97
Full text (6,28 MB)
This document has many files! More...

Abstract: Specimens of two uncommon fish species, Schedophilus medusophagus and Petromyzon marinus, were recently collected in nearshore waters off the island of Malta in the central Mediterranean. Several morphological and biological parameters for the specimens are described. The findings ascertain the occurrence of the two species in the area and corroborate furthermore the substantial contribution to wildlife sightings made through social media and by citizen scientists, thus further increasing knowledge on Mediterranean biodiversity.
Keywords: Centrolophidae, Petromyzontidae, Malta, Mediterranean Sea, citizen science
Published in DiRROS: 10.07.2026; Views: 171; Downloads: 131
Full text (1,83 MB)
This document has many files! More...