Biodiversidade e vulnerabilidade de ascidiacea no litoral do Rio de Janeiro frente aos cenários de introdução de espécies e mudanças climáticas

Abstract

Ascidians are sessile chordates that constitute one of the main groups of encrusting benthic animals in marine ecosystems. Knowing its diversity is an important way of evaluating impacts and their spatial and temporal distribution. Through data available in the literature and from three zoological collections (UFPR, MNUFRJ, UERJ), a list of ascidian species recorded on the coast of Rio de Janeiro (RJ) in the last 25 years (1998-2023) was consolidated. A total of 62 species have been recorded, distributed across 13 families and 32 genera, in the region between Rio das Ostras and Paraty. The region with the highest richness of ascidian species is the Green Coast, followed by Blue Coast. The number of species classified under the categories was 26 cryptogenic, 25 exotic and 11 native species. Between 2009 and 2019, two new records of the solitary sea squirts, Ciona robusta and Rhodosoma turcicum, were added to the southwest Atlantic Ocean, from Cabo Frio to Ilha Grande Bay (IGB), Brazil. Both species occurred in natural and artificial substrates, in predator-protected habitats, and regions close to harbors or other maritime activities. The distribution of C. robusta influenced by upwelling intensity and temperatures below 25°C, while R. turcicum was not sensitive to the range of recorded water temperatures. Rio de Janeiro has a history of intense vessel traffic along its coastline, in addition to several facilities such as ports, marinas, shipyards and marine farms, which favors the introduction and dispersion of marine invertebrate species. The analysis of the port movement of the Waterway Terminal of Angra dos Reis (TAAR) and the Port of Itaguaí, located in IGB and Sepetiba Bay (SB) respectively, between 2010-2020, pointed out that the main type of navigation in TAAR was cabotage and at the Port of Itaguaí it was a long haul. The Brazilian ports/terminals showed very high environmental similarity with IGB and SB as well as the Port of Busan (South Korea) and Singapore. Chinese ports, on the other hand, showed similarity considered high. The species Pyura vittata, Botryllus schlosseri, Perophora viridis, Didemnum candidum, Perophora multiclathrata, Herdmania momus, Botrylloides violaceus, Symplegma viride are the ones of greatest concern regarding the risk of introduction on the coast of RJ, as they have a history of introduction in other regions, have already been recorded near the main ports/terminals with the highest number of visits and the Port of Itaguaí and because their physiological tolerances in relation to temperature and salinity are favorable to the possible establishment of these species. Therefore, it is necessary to increase efforts in the knowledge of the physiology of the species and their interactions with the environment to understand the history of the distribution of these animals in RJ and in Brazil, as well as to monitor the introductions and their possible effects on benthic communities.