Introduced marine species in Croatian waters (Eastern Adriatic Sea) (2024)

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“…The Adriatic Sea counts more than 190 non-indigenous species [74]. In the Italian northern Adriatic 51 invasive species (39 of which in the Lagoon of Venice) have been recorded since 1945 [75], while 61 alien species (due to aquaculture activities and shipping) and 52 introduced (due to climate change) were recorded in Croatian waters [76]. Some invasive species, such as the green grape algae Caulerpa cylindracea and the red algae Womersleyella setacea, are known as habitat modifiers, reducing diversity and changing community structure in invaded areas compared to non-invaded sites [77].…”

confidence: 99%

et al. 2016

No abstract

Changing marine temperatures modify the distributional ranges of natural populations, but the success of invasion of new areas depends on local physical and ecological conditions. We explore the invasion by thermophilic species and their ecosystem effects by simulating a sea surface temperature (SST) increase using a trophodynamic model for the northern Adriatic Sea (NAS), in which thermal and trophic niches are explicitly represented for each thermophilic non-indigenous species (NIS) and native species. The NAS acts as a cul-de-sac for local species, preventing a further poleward migration as a response to temperature rise. In this situation, model results showed that effects of warming and invasion produced complex, non-linear changes on biomasses but never resulted in a complete overturn of a group of native species and/or a bloom of invasive ones. Despite this, the diversity index stabilizes at increased values after simulating invasion, possibly indicating that in such enclosed systems the establishment of invasive species could represent an enrichment in ecosystem structure. In addition, the absence of complete species substitution clearly showed the contribution of resident species toward increasing the resilience, i.e., the capability of the system to cope with invasion without changing substantially. Contrasting scenarios highlighted that changes in ecosystem primary production and species adaptation had secondary effects in ecosystem structure, while results for scenarios with different exploitation levels indicated that fishing can destabilize community structure in these change contexts, e.g., reducing community resilience. The results confirmed the importance of an ecological niche approach to analyze possible effects of invasion and highlighted the complexity of dynamics linked to temperature-driven species invasion', in terms of both the predicted strength of impacts and the direction of biomass change.

A B S T R A C TThe Pacific oyster (Crassostrea gigas) has a very important economic potential for aquaculture, but on the other hand, is among the highly invasive species in the world and within the Mediterranean ecosystem. In the 1960s, C. gigas was brought to Europe for aquaculture in the Mediterranean and Black Sea regions from Japan and Canada. The Turkish waters are the part of the Mediterranean Sea, which is the world's most invaded sea. The invasion of alien species results from marine transportation and aquaculture activities of non-native species. A heavy maritime traffic is also present in the Marmara Sea, which connects the Black Sea and Mediterranean Sea. The identification of the invasive species and their distributions is very prominent in terms of protecting natural habitat and monitoring the effects of invasive species. In this study, 30 individuals, morphologically identified as C. gigas, were collected from Bandırma bay. The genomic DNAs were extracted from each sample's muscle tissue using universal salt extraction method. Partial sequences of COI and 16S Mitochondrial DNA loci of the sample DNAs were obtained for species identification. The sequences were searched against the database and results were retrieved from BLAST. All the sequences obtained in this study showed significant similarity with the C. gigas sequences present in the database (E=0). The sample sequences resulted in 9 different haplotypes for the COI locus (hd: 0.5296 and variance: 0.01256±0.112) and 5 different haplotypes for the 16S rDNA locus (hd: 0.2529, Variance: 0.01076±0.104). The results of this study provided the first molecular evidence for the presence of non-native Pacific oyster individuals in the Marmara Sea.