In a work led by the IEO-CSIC in which researcher Alejandro de Carlos collaborated. The study confirms the northward expansion of typical specimens of tropical waters
The Marine Research Center (CIM) of the University of Vigo participated in a work led by the Spanish Institute of Oceanography (IEO-CSIC) that documents two new records of puffer fish in Galician waters and warns about the tropicalization of the sea.
The study, in which the Group for the Study of the Marine Environment (GEMM) and the Aquarium Finisterrae also collaborated, reviews for the first time the diversity of fish of the Tetraodontiformes order in Spain (a group that includes pufferfish, sunfish and pigfish) and confirms the northward expansion of species typical of tropical waters due to ocean warming and the progressive tropicalization of marine ecosystems.
The research, wich has just been published in the journal Fishes, analyzes the distribution of these species in Spanish waters and describes new records in Galicia of the blunthead puffer (Sphoeroides pachygaster) and the smooth puffer (Ephippion guttifer), two pufferfish species rarely found in this area. The specimens were caught off the Costa da Vela in 2021 and in the Ría de Pontevedra in 2025, respectively.
The role of CIM in genetic identification
The CIM, through researcher Alejandro de Carlos, collaborated in this research by carrying out the genetic confirmation of the specimens through ‘DNA barcoding’. “This is a molecular technique that allows biological species to be identified based on the analysis of a short and standardized sequence of their DNA. It works in a similar way to supermarket barcodes: each species has its unique genetic ‘signature’ in a specific fragment of its genome that allows it to be distinguished from others,” explains the CIM researcher.
Thanks to this methodology, it was possible to corroborate the initial taxonomic identification carried out by IEO staff through morphological analyses of the specimens. According to Alejandro de Carlos, “nowadays what is known as integrative taxonomy is practiced, whereby a specimen is identified with greater certainty by combining data from different disciplines, such as, in this case, morphology and DNA. The incorporation of molecular techniques has contributed to substantially improving taxonomic assignments and, also in ichthyology, constitutes an indispensable tool,” he explains.
Implications and follow-up
Some species of pufferfish contain toxins such as tetrodotoxin, one of the most potent natural neurotoxins known. Although the risk in Spain is low, since these species are not marketed and their sale is prohibited in the European Union, the work warns that the increase in their presence makes it necessary to strengthen scientific monitoring and the identification of potentially toxic species. To this end, a review of the presence of neurotoxic tetrodotoxins and paralyzing toxins in each of the listed species was carried out, which provides an updated overview of a little-explored field in European waters.
The study also includes an exhaustive review of all species of the order Tetraodontiformes recorded in Spanish waters, compiling historical and updated information. To date, 26 species belonging to five families have been documented throughout the Spanish territory, distributed in 22 species in the Canary Islands and 15 species in the Iberian Peninsula and the Balearic Islands.
“The increasing presence of tetraodontiform fish in Spanish waters provides further proof of the progressive tropicalization of the Spanish marine environment. Knowing the composition, geographical distribution and potential toxicity of the species is important for their early detection and alerting the population to the risks. In this way, food safety problems with potentially serious consequences derived from their accidental consumption can be prevented”, points out Rafael Bañón, researcher at the Vigo Oceanographic Center of the IEO and first author of the study.
The CIM has the CIGUS recognition of the Xunta de Galicia, which accredits the quality and impact of its research, and its activity is co-financed by the European Union through the FEDER 21-27 Program.
Source: DUVI
