This study investigated the distribution, abundance, and population structure of the invasive Procambarus clarkii in understudied small marginal water bodies along the Venice lagoon. These water bodies comprise expanses of brackish water, shallow freshwater canals, and small ponds, previously constituting part of a fishing valley. The aim was to fill the knowledge gap about the species colonization of these specific environments, analyse its relationships with the aquatic fauna and evaluate whether it could also inhabit coastal environments with increasing salinities. Sampling was conducted using fishing pots in 10 stations, each characterized by distinct environmental characteristics such as salinity, nutrient concentrations, water body width, water flow and floristic cover. The results showed that P. clarkii successfully invaded most of these marginal habitats. Although poor water quality and high nutrient levels do not preclude the presence of this species, they seem to influence its abundance. In contrast, salinity resulted to be a primary factor determining the presence or absence of the species, acting as a physiological barrier, limiting P. clarkii expansion toward more sea-influenced parts of the lagoon coastal environments. Moreover, pH, while not affecting the presence of the species, resulted in affecting the growth rates of individuals. In terms of community dynamics, the native nektonic fauna appears largely replaced by more adaptable non-native species, with P. clarkii likely contributing to this displacement, alongside other impacts. Moreover, although strong direct associations with specific aquatic fauna are limited, evidence suggests reciprocal predation between crayfish and fish during different life stages.
Common bottlenose dolphins Tursiops truncatus have adapted to foraging and scavenging behind fishing trawlers in many areas around the world. This opportunistic behaviour is widespread in Adriatic Sea waters off the region of Veneto, Italy. On October 1st, 2020, we tracked a group of bottlenose dolphins from a 6 m boat, north-east of the Po River Delta. The dolphins foraged behind midwater pair trawlers, then four individuals abandoned the vessels and engaged in fast, highly-directional movement toward another distant pair of midwater trawlers, at speeds of 8-14 km/h, as the trawlers moved away from the dolphins. After 29 min of fast directional travelling, the dolphins reached the midwater trawlers and immediately started foraging in their wake. GPS tracking of dolphin positions, combined with trawler positions obtained from AIS data matching vessel name/plate, revealed that the trawlers were 2.6 km away from the dolphins when the animals first appeared to have detected them – consistent with reports of detection-and-approach in other seas. While bottlenose dolphins in our 3,000 km2 study area frequently moved from one fishing trawler (or pair of trawlers) to the next, the trawlers’ detection-and-approach event reported here was the longest observed during our 7-year study, totalling 721 encounters with fishing trawlers and 17,432 km of survey effort during 129 days of monitoring trawling activities. Longdistance detection can theoretically enhance foraging opportunities, though the substantial negative effects of trawling on marine ecosystems make it difficult to disentangle causes and effects, and determine whether there may be net demographic benefits to the dolphins.
The Mediterranean Sea is significantly impacted by non-indigenous species (NIS) that have arrived through various routes, most notably shipping traffic. As a result, commercial harbours have become critical hotspots for these introductions. The Libyan coastline, particularly in the vicinity of major ports, is highly vulnerable to the arrival of NIS. During a targeted assessment of heterobranch biodiversity conducted from 2023 to 2025, the cephalaspidean Tubulophilinopsis lineolata was documented for the first time in both Libya and the Mediterranean Sea. This discovery highlights the urgent need for increased monitoring and for the creation of systematic biodiversity inventories covering Libya’s understudied coastal regions.
This study investigates the influence of environmental parameters on the abundance, biomass, and spatial distribution of demersal elasmobranchs in the eastern Sea of Marmara over a ten-year period (2014–2024). Catch per unit effort (CPUE) data from bottom trawl surveys were combined with in situ measurements of dissolved oxygen, temperature, salinity and depth. Multivariate analyses indicate that dissolved oxygen and temperature are key factors associated with spatial variability of demersal elasmobranchs in the investigated area. Temporal patterns show an increase in their abundance until the late 2010s, followed by a marked decline, which may reflect increasing environmental stress as a cause of the decline. These findings suggest that ongoing deoxygenation, together with other environmental parameters, may play an important role in structuring demersal elasmobranch assemblages in the region.
The introduction of non-indigenous species (NIS) into the Mediterranean Sea represents a growing ecological concern, driven by multiple vectors including shipping, aquaculture, and climate-mediated range expansions. In this study, we report the first Mediterranean record of the Japanese amberjack Seriola quinqueradiata Temminck & Schlegel, 1845 (Carangidae), a species native to the northwestern Pacific Ocean. A specimen was captured by an angler on 13 February 2026 along the coast of Nardò (Ionian Sea, Italy), near Zone C of the Porto Cesareo Marine Protected Area. Species identification was confirmed through an integrative taxonomic approach combining morphological examination and mitochondrial COI gene barcoding. A second specimen, likely belonging to the same species, was captured shortly thereafter in the same area. The most plausible introduction pathways were discussed. This finding highlights the importance of continuous monitoring of marine biodiversity, particularly through the integration of citizen science and fisheries observations, which are essential for the early detection of rare and potentially invasive species.
