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The introduction and establishment of the bivalves Isognomon bicolorand Isognomonaff. legumenin the South Aegean Sea, specifically on the islands of Chalki and Alimia, marks a significant ecological event. These species, native to different parts of the world, have now been confirmed in the Mediterranean through DNA barcoding and phylogenetic analyses. These methods are crucial for accurate identification within the genus Isognomon, as traditional morphological identification is challenging due to the variable and habitat-dependent shell shapes of these bivalves. Isognomon bicoloris originally from the West Atlantic, while  Isognomonaff. legumenhails from the Indo-Pacific region. Their presence in the Mediterranean, specifically in the intertidal and shallow subtidal zones, indicates they have found suitable habitats in their new environment. Over a four-year period of field observations, researchers gathered valuable ecological data, noting the species’ habitat preferences and their establishment dynamics. In July 2024, researchers observed the formation of new, extensive dense aggregations, or beds, of the invasive I. bicoloron the coastal rocks of Chalki and Alimia. The formation of these beds is a clear indicator of a progressing invasion, which poses a significant threat to the native ecosystem. The establishment of I. bicolorandI. aff. legumencould disrupt local biodiversity, outcompete native species, and alter the ecological balance in these regions. This situation underscores the importance of continuous monitoring and the use of advanced identification techniques like DNA barcoding to track and manage invasive species. Such efforts are essential to mitigate the impacts of these invasions and protect native marine ecosystems.

Seafood labels play an increasingly key role in assisting consumers in purchasing processed and featureless fish products, and in encouraging sustainable fishing and aquaculture practices. While informed purchasing choices are typically influenced by traceability and labelling awareness, they also depend on the consumers’ ability to identify and discriminate the fish species available on the market, which to date remains notably unexplored. We asked 720 people across six European countries to identify pictures of six fish species commonly sold in Europe. We reveal that European consumers have a poor understanding of the appearance of the fish they consume (overall ∼ 30% correct identification), with British consumers performing the poorest and Spanish ones doing best. We noted cultural association with some species, whereby the most regionally consumed fish are more easily recognized. We argue that despite recent improvements in technological solutions, stakeholder dialogue, and policy implementation, seafood market transparency will remain open to malpractice until consumers restore connection with their food.

The globally distributed heterotrophic dinoflagellate Noctiluca scintillans(Macartney) Kofoid & Swezy is well known for its dense blooms and prominent displays of bioluminescence. Intriguingly, along the west coast of the U.S.A., its blooms are not bioluminescent. We investigated the basis for this regional loss of bioluminescence using molecular, cellular, and biochemical analyses of isolates from different geographic regions. Several prominent differences were identified in the nonbioluminescent strains: (1) the fused luciferase and luciferin binding protein gene (lcf/lbp) was present but its transcripts were undetectable; (2) lcf/lbpcontained multiple potentially deleterious mutations; (3) the substrate luciferin was absent, based on the lack of luciferin blue autofluorescence and the absence of luciferin‐derived metabolites; (4) although the cells possessed scintillons, the organelles that contain the luminescent chemistry, electron microscopy revealed additional scintillon‐like organelles with an atypical internal structure; and (5) cells isolated from the California coast were 43% smaller than bioluminescent cells from the Gulf of Mexico. Phylogenetic analyses based on large subunit rDNA did not show divergence of the nonbioluminescent population in relation to bioluminescent N. scintillansfrom the Pacific Ocean and Arabian Sea. This study demonstrates that gene silencing and the lack of the luciferin substrate have resulted in the loss of an important dinoflagellate functional trait over large spatial scales in the ocean. As the bioluminescence system of dinoflagellates is well characterized, nonbioluminescent N. scintillansprovide an ideal model to explore the evolutionary and ecological mechanisms that lead to intraspecific functional divergence in natural dinoflagellate populations.