Ascidians at Currais islands, Paraná, Brazil: taxonomy and distribution

Abstract

The Currais Islands is a group of a few small rocky islands in the state of Paraná, in southern Brazil, which provides an interesting location for the study of ascidians. Subtidal diversity is very high and the islands have recently been proposed as a Conservation Unit. A field study was established on the largest island to understand ascidian distributions on spatial and temporal scales. Transects, sampled three times during 2002 and 2003, were established on northern and southern locations of the island as well as at three depths. Twenty species were recorded; the most common were Didemnum rodriguesi, Didemnum speciosum and Didemnum granulatum. Three species are possibly new and will be described elsewhere. An additional nine are new records for the state of Paraná: Perophora regina, Didemnum speciosum, Trididemnum orbiculatum, Eudistoma carolinense, Aplidium pentatrema, Molgula phytophila, Botryllus tuberatus, Symplegma brakenhielmi and Polyandrocarpa anguinea. While all these species are distributed between 6 and 15 m, there is a tendency to reduction of abundance towards 15 m in several species. Some species appear to prefer the north side of the island. Several species show temporal changes in abundance, with some being most common in the spring and others in the summer, but we can not affirm yet that there is a seasonal pattern between years.Key words: Ascidiacea, Tunicata, taxonomy, spatial distribution, temporal distribution. ResumoAs Ilhas Currais são formadas por um grupo de três pequenas formações rochosas localizadas no Estado do Paraná, sul do Brasil, sendo um local de interesse para o estudo do grupo Ascidiacea. A diversidade da região sublitoral local é bastante alta, e Currais foi recentemente proposto como local a ser transformado em Unidade de Conservação. Foi desenvolvido um estudo de campo na maior das três ilhas, com o intuito de se conhecer a distribuição espacial e temporal de ascídias. Foram realizadas três amostragens entre 2002 e 2003, nos lados norte e sul da ilha, em três diferentes profundidades. Vinte espécies foram registradas, sendo as mais comuns Didemnum rodriguesi, Didemnum speciosum e Didemnum granulatum. Três são possíveis espécies novas e serão descritas futuramente. Nove espécies representam novos registros para o Estado do Paraná: Perophora regina, Didemnum speciosum, Trididemnum orbiculatum, Eudistoma carolinense, Aplidium pentatrema, Molgula phytophila, Botryllus tuberatus, Symplegma brakenhielmi e Polyandrocarpa anguinea. As espécies encontram-se distribuídas principalmente entre a faixa dos seis aos 15 m, tendo sido observada uma redução da abundância em profundidades maiores de 15 m. Algumas espécies parecem preferir o lado norte da ilha. Algumas espécies apresentam variações temporais de abundância, sendo mais comuns ou na primavera ou no verão, mas não é possível ainda afirmar que exista um padrão sazonal entre anos. Palavras

Biodiversity of benthic macroinvertebrates on hard substrates in the Currais Marine Protected Area, in southern Brazil

“…Three of the 12 species found previously but not in this study were probably NIS: the ascidians Aplidium pentatrema (Monniot F., 1972), Eudistoma carolinense Van Name, 1945 and Diplosoma sp. (Rocha & Faria 2005). Also, the NIS Ascidia tenue Monniot, 1983 was only found on recruitment plates in /2009(Bumbeer & Rocha 2012.…”

“…The only invertebrate taxon oriented inventory at Currais MPA (Rocha & Faria 2005) also provides the opportunity to demonstrate additional changes to community composition. Three of the 12 species found previously but not in this study were probably NIS: the ascidians Aplidium pentatrema (Monniot F., 1972), Eudistoma carolinense Van Name, 1945 and Diplosoma sp.…”

“…Symplegma rubra Monniot, 1972 was recorded only within the Paranaguá Estuarine Complex before 2005 (Rocha & Kremer 2005), yet now it is common in Currais MPA. As S. rubra is quite easily encountered and identified, by the large, brightly colored, colonies (Figure 5h), it is unlikely that, if present, it would have passed unnoticed in the 2002/2003 ascidian inventory (Rocha & Faria 2005). Thus, while probably introduced due to its first records in estuarine areas and recent new occurrences, the lack of genetic information on a global scale leads us to call it cryptogenic.…”

“…Previous studies of the marine environment tended to focus on the ichthyofauna (Félix & Harckradt 2008, Harckradt & Félix-Harckradt 2009, Daros et al 2012. Only one study examined the soft bottom infauna (Lorenzi & Borzone 2009), three examined benthic invertebrates on hard substrates, one of ascidians (Rocha & Faria 2005) and two experimental studies on temporal colonization of artificial substrates near the islands (Brandini & Silva 2011, Bumbeer & Rocha 2012. Since the creation of the MPA, there has been only one study of marine biota, which examined the algal community (Pellizzari et al 2014).…”

Non indigenous ascidians in port and natural environments in a tropical Brazilian bay

“…comm. 2002), southeast (RODRIGUES et al 1998, ROCHA & COSTA 2005 and south , ROCHA & FARIA 2005. At Angra dos Reis, S. brakenhielmi is very common and often found during the last 10 years (SILVA pers.…”