Westward expansion of the brown shrimp <i>Penaeus aztecus</i> Ives 1891 (Decapoda: Penaeidae) in the Mediterranean Sea: a review on the Mediterranean distribution and first record from Spain

Penaeus aztecus Ives 1891, commonly known as the brown shrimp, is a well-established invasive alien species of Atlantic origin in the Mediterranean Sea. Here we report on the presence of the species in the Balearic Sea, eastern Mediterranean coast of Spain, where seven specimens were caught in 2023 (February, May and July). Our records represent the first from Mediterranean Spanish waters, as well as the westernmost for this species in the whole basin. Furthermore, on the basis of the data collected, we suggest the presence of a well-established population in this part of the basin. We provide a review on the Mediterranean distribution of the species with discussion on possible pathways of introduction and implications for the ecosystem and fisheries.