A New Signal of Tropicalization in the Northeast Atlantic: The Spread of the Spotfin Burrfish Chilomycterus reticulatus in Madeira Archipelago and Its Invasion Risk

Abstract

Current trends in the global climate facilitate the displacement of numerous marine species from their native distribution ranges to higher latitudes when facing warming conditions. In this work, we analyzed occurrences of a circumtropical reef fish, the spotfin burrfish, Chilomycterus reticulatus (Linnaeus, 1958), in the Madeira Archipelago (NE Atlantic) between 1898 and 2021. In addition to available data sources, we performed an online survey to assess the distribution and presence of this species in the Madeira Archipelago, along with other relevant information, such as size class and year of the first sighting. In total, 28 valid participants responded to the online survey, georeferencing 119 C. reticulatus sightings and confirming its presence in all archipelago islands. The invasiveness of the species was screened using the Aquatic Species Invasiveness Screening Kit. Five assessments rated the fish as being of medium risk of establishing a local population and becoming invasive. Current temperature trends might have facilitated multiple sightings of this thermophilic species in the Madeira Archipelago. The present study indicates an increase in C. reticulatus sightings in the region. This underlines the need for updated comprehensive information on species diversity and distribution to support informed management and decisions. The spread of yet another thermophilic species in Madeiran waters provides further evidence of an ongoing tropicalization, emphasizing the need for monitoring programs and the potential of citizen science in complementing such programs.

Expanding north: first record of the beaded sea cucumber Euapta lappa at Madeira Island

“…This warming promotes the progressive tropicalization of the area, with previously strictly tropical species expanding their distributional limit northwards to Madeira (e.g. Bianchi et al ., 1998; Wirtz & Berenger, 2017; Schäfer et al ., 2019; Castro et al ., 2021). In this context, an increasing number of tropical species has been recorded at Madeira, including crustaceans, algae and fish (Ribeiro et al ., 2019; Schäfer et al ., 2019; Castro et al ., 2021).…”

“…Bianchi et al ., 1998; Wirtz & Berenger, 2017; Schäfer et al ., 2019; Castro et al ., 2021). In this context, an increasing number of tropical species has been recorded at Madeira, including crustaceans, algae and fish (Ribeiro et al ., 2019; Schäfer et al ., 2019; Castro et al ., 2021).…”

“…In recent years an increasing number of non-indigenous species (NIS) has been recorded at Madeira Island (Castro et al ., 2022), with many representing northern range expansions (e.g. Wirtz & Berenger, 2017; Ribeiro et al ., 2019; Schäfer et al ., 2019; Castro et al ., 2021). This new record of the beaded sea cucumber, E. lappa , at Madeira Island adds to the growing list of tropical species recorded in the study region.…”

Tropicalization alert: new species of mat-forming zoantharian (Zoanthus pulchellus) arrives on Madeira Island (NE Atlantic)

“…Before this discovery, Z. pulchellus in the eastern Atlantic was limited to the Canary Islands (López et al 2019), where it negatively affected native reef fish and local benthic communities by reducing macroalgae coverage (Moreno-Borges et al 2022). The introduction of non-indigenous species to oceanic islands (Castro et al 2021) has been increasing due to globalization, climate change, and international maritime traffic. Moreover, the increase in seawater temperatures has promoted the process of "tropicalization," i.e., tropical species advancing into subtropical and temperate latitudes (Schäfer et al 2019, Castro et al 2021.…”

“…The introduction of non-indigenous species to oceanic islands (Castro et al 2021) has been increasing due to globalization, climate change, and international maritime traffic. Moreover, the increase in seawater temperatures has promoted the process of "tropicalization," i.e., tropical species advancing into subtropical and temperate latitudes (Schäfer et al 2019, Castro et al 2021.…”