Search Results (8)

The Mediterranean Sea is a major biodiversity hotspot increasingly affected by biological invasions, climate warming, and habitat degradation. Among the most successful invaders are the rabbitfish species Siganus luridus and Siganus rivulatus, Lessepsian migrants from the Red Sea that are now widespread across the eastern Mediterranean. This study examined how these invasive herbivores influence native herbivore assemblages in shallow coastal habitats around Lipsi Island in the Aegean Sea, Greece. Using Underwater Visual Census (UVC) surveys and in situ feeding observations, we quantified the abundance and grazing activity of invasive rabbitfish relative to that of the native herbivores Sparisoma cretense and Sarpa salpa. Invasive rabbitfish represented approximately 35% of the herbivore assemblages and showed clear habitat and dietary preferences. Significant negative correlations were observed between invasive foraging activity and the feeding rate of the native S. cretense, while no such effect was found for S. salpa. High habitat overlap between S. luridus and S. cretense suggests that this native species may be more susceptible to competition on rocky substrates. Evidence of partial resource partitioning was observed, including increased use of seagrass habitats by S. salpa. These findings highlight how invasive herbivores can restructure native herbivore communities and alter grazing dynamics in eastern Aegean coastal ecosystems. Given the ongoing sea warming and widespread decline of seagrass habitats across the Mediterranean, understanding these competitive interactions is therefore essential for assessing future biodiversity trajectories and informing management strategies. Full article

The occurrence of the bigfin reef squid Sepioteuthis lessoniana, a Lessepsian migrant, is documented for the first time from the coastal waters off Malta, based on the collection of a single specimen reported through citizen science. The presence of this species in the broader Strait of Sicily region is further confirmed by a morphometric assessment and genetic analysis of another individual captured off the Pelagian island of Lampedusa. Molecular identification using mitochondrial COI and 16S rRNA markers corroborates the taxonomic identification exercise as it aligns both specimens with Indo-Pacific clades of S. lessoniana. These records represent the first genetically verified occurrences of the species in both Maltese and Italian waters. The findings extend the known Mediterranean distribution of S. lessoniana, emphasizing the Strait of Sicily as an important monitoring region for Lessepsian migrants and highlighting the combined role of integrative taxonomy and citizen science in tracking non-indigenous species introductions. Full article

The common lionfish, Pterois miles (Bennett, 1828), is one of the most recent Lessepsian migrants into Mediterranean Sea. In this study, a first attempt is made to explore some life history parameters of the species in the Messenian Gulf (SW Greece). Its growth, morphometry, and feeding behavior were studied in samples collected with a speargun during the summer and autumn of 2021 at depths from 0 m to 20 m. Lionfish were found to have established a thriving population, growing faster and reaching larger sizes than in their native range. Analysis of their diet showed that this species is a generalized feeder with a preference towards piscivory, targeting key species for local food webs, such as the damselfish (C. chromis), possibly provoking competition with other native predators. Overall, the dietary habits of the species, rapid growth rate, and lack of predation pressure make the lionfish an additional risk for the integrity of the Messenian marine ecosystem, an ecosystem which is already disturbed by intense human intervention. Full article

The alien Red Sea goatfish, Parupeneus forsskali (Fourmanoir & Guézé, 1976), is a Lessepsian migrant, entering the Mediterranean through the Suez Canal. This study explores its seasonal diet and biological traits in Cyprus, its non-native habitat. From August 2019 to July 2021, a total of 249 specimens were collected, ranging in total length (TL) from 5.8 to 27.7 cm, with a mean TL of 15.1 ± 4.54 cm (SD). These specimens were examined with respect to sex and season. Through various methods (F%, N%, W%, and IRI), the feeding habits of the species were analysed, revealing a diet dominated by Crustacea (mainly Decapoda) and Polychaeta, with the secondary consumption of Mollusca, Echinodermata, and others. Significant differences were found between males and juveniles and females and juveniles, with adults preferring Decapoda and juveniles Copepoda, while seasonal variations were mainly influenced by prey availability. The Red Sea goatfish exhibited ontogenetic niche shifts in its depth and habitat distribution, influenced by size and age. The trophic level (TROPH) of P. forsskali ranged from 3.22 to 3.46, corresponding to an omnivorous diet with a preference for animals. These findings suggest that P. forsskali is an opportunistic predator with a diverse diet, thriving in its new habitat and potentially impacting the local marine food webs by competing with economically important native species for resources. Full article

Bio-invasions have the potential to provoke cascade effects that can disrupt natural ecosystems and cause ecological regime shifts. The Mediterranean Sea is particularly prone to bio-invasions as the changing water conditions, evoked by climate change, are creating advantageous conditions for Lessepsian migrants from the Red Sea. Recently, in May 2023, a new alien species was documented in the Mediterranean Sea—a soft coral of the genus Dendronephthya. This discovery was made by divers conducting ‘Long-Term Ecological Research’ surveys, along the coast of Israel, at a depth of 42 m. Genetic and morphological testing suggest that the species identity may be Dendronepthya hemprichi, an Indo-Pacific coral, common in the Red Sea. According to life history traits of this species, such as accelerated attachment to available surfaces and fast growth, we expect it to rapidly expand its distribution and abundance across the Mediterranean Sea. Full article

In the present study, we investigated the different ecological characteristics of native and non-native demersal fish collected in 2014–2015 on the shelf of the Antalya Gulf in the Eastern Mediterranean Sea. Lessepsian migrants originating from the Indo-Pacific Ocean were classified as non-indigenous species (NIS) and the other species, which were mostly Atlanto-Mediterranean, were classified as indigenous species (IS). The results showed that the faunistic characteristics of IS and NIS differed significantly in space but only partly over time. The density and species diversity of the IS increased with the seafloor depth, while the opposite pattern was observed for the NIS, which were found mostly in shallow waters. Proximity to rivers and Posidonia oceanica meadows and the presence of a marine protected area (MPA) were also important factors determining the differences in the ecological characteristics of IS and NIS. The ecological ordination of the fish assemblages in the canonical correspondence analysis (CCA) space was V-shaped for the IS and =-shaped for the NIS, and it was mainly determined by bottom depth. Altogether, the ordination took the shape of a double strikethrough (V) due to the NIS filling an available niche. Hierarchically, the NIS (“occupiers”) and IS (“resisters”) shared the shallowest waters, while the middle-shelf waters were occupied by NIS (“gapers”) and IS (“escapers”) separately. The upper shelf was occupied only by IS (“homekeepers”) and “minorities” of NIS. Finally, we identified eight factors as ecological indicators of NIS and IS: bottom depth, bottom vegetation status, fish hierarchy, key species, water productivity, fish trophic level, life strategy and morphometry. Full article

Seagrasses harbour bacterial communities with which they constitute a functional unit called holobiont that responds as a whole to environmental changes. Epiphytic bacterial communities rapidly respond to both biotic and abiotic factors, potentially contributing to the host fitness. The Lessepsian migrant Halophila stipulacea has a high phenotypical plasticity and harbours a highly diverse epiphytic bacterial community, which could support its invasiveness in the Mediterranean Sea. The current study aimed to evaluate the Halophila/Cymodocea competition in the Aegean Sea by analysing each of the two seagrasses in a meadow zone where these intermingled, as well as in their monospecific zones, at two depths. Differences in holobionts were evaluated using seagrass descriptors (morphometric, biochemical, elemental, and isotopic composition) to assess host changes, and 16S rRNA gene to identify bacterial community structure and composition. An Indicator Species Index was used to identify bacteria significantly associated with each host. In mixed meadows, native C. nodosa was shown to be affected by the presence of exotic H. stipulacea, in terms of both plant descriptors and bacterial communities, while H. stipulacea responded only to environmental factors rather than C. nodosa proximity. This study provided evidence of the competitive advantage of H. stipulacea on C. nodosa in the Aegean Sea and suggests the possible use of associated bacterial communities as an ecological seagrass descriptor. Full article

Halophila stipulacea is a well-known invasive marine sea grass in the Mediterranean Sea. Having been introduced into the Mediterranean Sea via the Suez Channel, it is considered a Lessepsian migrant. Although, unlike other invasive marine seaweeds, it has not demonstrated serious negative impacts on indigenous species, it does have remarkable invasive properties. The present in-silico study reveals the biotechnological features of H. stipulacea by showing bioactive peptides from its rubisc/o protein. These are features such as antioxidant and hypolipideamic activities, dipeptidyl peptidase-IV and angiotensin converting enzyme inhibitions. The reported data open up new applications for such bioactive peptides in the field of pharmacy, medicine and also the food industry. Full article