The invasive silver-cheeked toadfish (Lagocephalus sceleratus) predominantly impacts the behavior of other non-indigenous species in the Eastern Mediterranean

Marine invasive species are pervasive across the world’s coastal regions. Nevertheless, empirical quantification of their ecological effects remains limited. Here, we elucidate the interaction of the invasive silver-cheeked toadfish, Lagocephalus sceleratus, with the fish community of the Eastern Mediterranean Sea, a hotspot for marine biological invasions. We deployed 88 underwater stereo-video systems across the Israeli continental shelf and upper slope. From this data, we quantified the change in fish behavior in the absence and presence of L. sceleratus. We further supported our findings by analyzing L. sceleratus gut contents. Our results indicated that the presence of L. sceleratus significantly deterred other non-indigenous species (NIS) and we recorded multiple NIS escape behaviors (fleeing, covering beneath sand or algae, or using camouflage). However, indigenous species (IS), for the most part, remained indifferent to L. sceleratus’ presence. Furthermore, analysis of gut contents supported the visual surveys and revealed that L. sceleratus primarily feed on NIS, including other non-indigenous pufferfish species. Our findings suggest that harmful invasive species may not necessarily be detrimental to IS. At the same time, the apparent threat by L. sceleratus may have ecological impacts on other NIS, especially invasive pufferfishes which are highly poisonous and are suspected to have few predators in the Mediterranean Sea.