ABSTRACT The number of biological invasions has grown dramatically in recent decades, as well as the world's human population and coastal development. Anthropogenic habitats, such as pier pilings and break waters, have been constantly added to marine environment, usually concentrated in estuarine areas. These habitats are focal points for marine invasions, but relatively little is known about the spread of non-indigenous species (NIS) to nearby natural habitats. This study aimed to determine the extent to which NIS have spread to natural substrates both inside estuarine areas and in the adjacent open sea. We conducted a field survey and a literature review, which have been critically discussed and validated. The updated NIS list of benthic invertebrates comprises 19 species: Ascidiacea (5), Cirripedia (5), Cnidaria (3), Mollusca (3), Polychaeta (1), Decapoda (1), and Echinodermata (1). Our results suggested substantial spread of non-indigenous species into natural substrates. Altogether, 18 and 16 NIS were recorded in artificial and natural substrata, both representing 13% of the total species in each habitat. The percentage of NIS was more pronounced in the estuarine areas, 17.6% in artificial habitats and 18.6% in natural ones. Programs developed for the monitoring of marine invasion have to broaden their focus including natural areas adjacent to ports and marinas, to follow the spread and impact of NIS on these areas.

Resumo Este estudo descreve a biodiversidade da comunidade de invertebrados bênticos de ambientes rochosos da Área Marinha Protegida de Currais (AMP Currais), localizada no estado do Paraná. A comunidade bêntica foi amostrada entre 2012 e 2015, durante períodos de inverno e verão, em duas ilhas e quatro grupos de recifes artificiais (RAs). As amostras foram obtidas em transecções rasas (2-4 m) e mais profundas (6-8 m) nas ilhas e a ~18 m nos RAs. Também foi realizada uma pesquisa bibliográfica para examinar todos os registros de invertebrados bênticos publicados para a área da AMP Currais. Foram encontrados 176 táxons pertencentes aos filos Annelida (classe Polychaeta), Arthropoda (classe Maxillopoda, ordem Sessilia), Bryozoa, Cnidaria, Chordata (classe Ascidiacea), Echinodermata, Mollusca e Porifera, distribuídos em 13 classes, 40 ordens e 75 famílias. Há 102 novos registros para a área, representando 58% de todas as espécies registradas. Destes, 58 táxons não haviam sido registrados anteriormente no estado do Paraná. Este notável número de novos registros revela a falta de estudos sobre a biodiversidade no litoral do Paraná. Quinze espécies exóticas foram encontradas, e uma espécie em extinção, a estrela-do-mar Coscinasterias tenuispina. Esta é uma importante área de transição para acompanhar a expansão ou constrição da distribuição latitudinal das espécies, considerando as alterações climáticas que poderão influenciar na distribuição geográfica das espécies (tanto nativas quanto invasoras). O presente estudo constitui o primeiro inventário dos habitats de substrato rochoso da AMP Currais e revela grande biodiversidade.

Abstract This study describes the biodiversity of benthic invertebrates on hard substrates in the Currais Marine Protected Area (Currais MPA), in the state of Paraná. The benthic community was sampled during 2012 to 2015, in winter and summer, at two islands and four groups of artificial reefs (ARs). Samples were collected along shallow (2-4 m) and deep (6-8 m) transects at the islands and ~18 m transects at the ARs. We also searched the literature to review all published records of benthic invertebrates on hard substrates in the Currais MPA. We recorded 176 taxa in the phyla Annelida (class Polychaeta), Arthropoda (class Maxillopoda, order Sessilia), Bryozoa, Cnidaria, Chordata (class Ascidiacea), Echinodermata, Mollusca and Porifera, in 13 classes, 40 orders and 75 families. With these 102 new records, our list comprises 58% of all recorded species. Of these, 58 taxa were first records for the state of Paraná. This remarkable number of new records highlights that biodiversity studies are lacking in Paraná. Fifteen non-indigenous species and one endangered species, the sea star Coscinasterias tenuispina (Lamarck, 1816), are included. This is an important transitional area to monitor expansion or constriction of the latitudinal distributions of species, in the context of climate change, that may influence the geographical distribution of species (both native and invasive). This study is the first inventory of marine hard substrate habitats of the Currais MPA with a surprisingly diverse community.

Invasion by marine species, often considered a grave threat to marine ecosystems, occurs throughout the world as a consequence of many anthropogenic activities. In coastal Paraná, many factors including shipping, aquaculture and the use of artificial substrates provide suitable environments for the establishment and rapid spread of introduced marine species. To better understand this process, the encrusting community was studied on polyethylene plates (n = 120, 10 x 10 cm) that were placed seasonally at fixed locations on the inner continental shelf to detect non-native species. Of the 62 taxa found, 40 were identified to species, 14 of which were native, 9 introduced and 17 cryptogenic. We found a new introduction while most introduced species were previously reported at a nearby estuary with an international port. Possible complementary explanations for these detections are 1) estuaries influence ecological processes on the inner continental shelf, 2) the study area is near the route of cargo and other ships entering the port, 3) other local vectors, such as hulls of fishing and recreational boats, and artificial reefs link the estuary to the offshore areas. Thus, not only are estuaries invaded by exotic species, but also non-indigenous marine species may be present in the open sea where they are likely to colonize artificial substrates.