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Marine Turtle Newsletter 94:7-9, © 2001

Marine Turtle Newsletter-Online

Commensal Barnacles of Sea Turtles in Brazil

Leandro Bugoni1,2, Lígia Krause1, Alexandre Oliveira de Almeida3 & Alessandra Angélica de Pádua Bueno3
1Laboratório de Herpetologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Paulo Gama, 110, CEP 90.040-060, Porto Alegre - RS, Brazil
2Current address: Departamento de Oceanografia, Fundação Universidade Federal do Rio Grande, C.P.474, CEP 96.201-900, Rio Grande-RS, Brazil (E-mail: pgoblb@super.furg.br)
3Laboratório de Carcinologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Brazil (E-mail: almeidaao@uol.com.br; alebueno@vortex.ufrgs.br)

A variety of marine organisms occur as symbionts of green (Chelonia mydas) and loggerhead (Caretta caretta) sea turtles (Dodd 1988; Hirth 1997). Among the commensal symbionts associated with C. mydas and C. caretta, stalked and encrusting barnacles occur with high frequency (Caine 1986; Dodd 1988; Hirth 1997). Unfortunately, the literature focusing on carapace epibionts is scattered in taxon specific articles that are largely hidden from turtle biologists (Caine 1986). An example of Caine’s assertion is the absence of records of commensal barnacles collected in Brazil on green turtles (Hirth 1997) in spite of the published records of barnacles on sea turtles from this country (e.g. Young 1990; 1991). According to Young (1999), the cirriped fauna of Rio Grande do Sul, the southernmost state of Brazil, shows high diversity of species, composed by Subantarctic Argentine species and Subtropical Brazilian species. Although, there are a few records of barnacle species associated with other zoological groups from the region (Young 1999). In this paper we present data on the occurrence of barnacles associated with green and loggerhead turtles from southern Brazil. Additionally, we provide a summary of past studies that report the occurrence of commensal barnacles collected from sea turtles in the Brazilian territory.

Barnacles were collected from the carapaces of dead stranded sea turtles encountered on the beaches of the State of Rio Grande do Sul, Brazil, between Torres (29°20’S; 49°44’W) and Arroio Chuí (33°45’S; 53°22’W) from August 1997 to May 1998. All of the green turtles examined were juveniles (mean Curved Carapace Length (CCL)38.3cm, SD 1.96cm, range 35-43cm, n=13). The loggerheads examined represented subadult and adult size classes (mean CCL 72.2cm, SD 11.5cm, range 63-98cm, n=9). Barnacles were obtained by scraping the turtle carapace or by removing scutes. Samples were preserved in 70% ethanol.

The present study recorded seven barnacle species associated with sea turtles in southern Brazil (Table 1). Four barnacle species (Balanus improvisus, B. venustus, Conchoderma virgatum, and Lepas anatifera) were previously unknown associates of sea turtles in Brazilian waters. Three species (B. venustus, C. virgatum and L. anatifera) occurred only on C. mydas. One barnacle species (Platylepas sp.) occurred only on C. caretta.

Table 1
Table 1. Commensal barnacles on stranded green and loggerhead turtle in southern Brazil, with a review of records from the Brazilian territory. (*) Species not recorded in the present study; (**) data not obtained;letters in parentheses indicate references that have previously reported barnacle species from Brazilian turtles. "A" refers to Young (1990; turtle host species not specified), "B" refers to Young (1991), "C" refers to Farrapeira-Assunção (1991), "D" refers to Serafini &Soto (2000).

Platylepas hexastylos and Chelonibia testudinaria were the most frequent barnacles associated with green turtles. The former species was also the most frequent commensal barnacle collected from loggerheads (Table 1). Both P. hexastylos and C. testudinaria have been previously documented to associate with green and loggerhead turtle populations around the world (Dodd 1988; Hirth 1997). Chelonibia testudinaria was the most common barnacle found on loggerheads in the United States (Caine 1986), as well as the most common barnacle observed on green turtles in Australia (Limpus et al. 1994). Interestingly, C. testudinaria was not collected from any of the nine loggerhead specimens in this study. Two Balanus species (B. improvisus and B. venustus) were found in this study. Balanus improvisus occurred on both green and loggerhead turtles in profuse incrustations. Despite the extensive records of Balanus spp. associated with live sea turtles (e.g. Caine 1986; Frick et al. 2000; Lutcavage & Musick 1985), balanids are not obligate commensal barnacles (Foster 1987). Recruitment of the barnacles may occur on dead and drifting specimens, especially coastal and fast growing barnacle species, as Balanus spp. On the other hand, some cirriped species may dissociate from dead sea turtles as occurs with other commensal taxa, which are rarely found on dead stranded sea turtles. An interesting topic for further studies would be to compare commensal assemblages from stranded sea turtles with those from live or recently dead sea turtles in the same area.

The number of barnacle specimens per host turtle ranged from 1 to 70 (Table 1). Individual turtles hosted up to three different barnacle species. Associations were recorded between Balanus improvisus/B. venustus/Lepas anatifera; B. improvisus/Platylepas hexastylos/Platylepas sp.; and Conchoderma virgatum/L. anatifera. In general, barnacles were attached to the anterior marginal scutes and to posterior 1/3 of the carapace, as described by Caine (1986). Platylepas hexastylos were tightly encrusted on the hosts causing deep lesion at soft parts of the turtles.

Prior to our study, Balanus improvisus was unknown as an associate of loggerhead and green turtles. In the same way, B. venustus and Lepas anatifera were also unknown commensals of green turtles (Hirth 1997). Conchoderma virgatum and Platylepas sp. are the first records from Rio Grande do Sul, according to Young (1999). Lepas hilli, Chelonibia caretta, Platylepas decorata, Stomatolepas elegans and S. transversa are recorded for Brazil as symbionts with sea turtles, but were not found in this study (Table 1).

Acknowledgements: We are grateful to Paulo S. Young, of the National Museum, Rio de Janeiro, for helping with identification of barnacles, Maria Virgínia Petry, of Universidade do Vale do Rio dos Sinos, for logistic facilities in field work and J. Frazier and M. Frick for comments on the manuscript. Funds were provided by UNESCO and PIBIC-UFRGS/CNPq.

CAINE, E.A. 1986. Carapace epibionts of nesting loggerhead sea turtles: Atlantic coast of U.S.A. Journal of Experimental Marine Biology & Ecology 95:15-26.

DODD, C.K JR. 1988. Synopsis of the biological data on the loggerhead sea turtle Caretta caretta (Linnaeus 1758). U.S. Fish and Wildlife Service. Biological Report 88:1-110.

FARRAPEIRA-ASSUNÇÃO, C.M. 1991. Revisão do gênero Chelonibia Leach, 1817 na costa brasileira (Crustacea, Cirripedia). Salvador. Abstracts of XVIII Congresso Brasileiro de Zoologia, pp. 133.

FOSTER, B. 1987. Barnacle ecology and adaptation. In: A. SOUTHWARD (Ed.). Barnacle ecology. Rotterdam, AA Balkema. pp. 113-133.

Frick, M.G., K.L. Williams, D. Veljacic, L. Pierrard, J.A. Jackson & S.E. Knight. 2000. Newly documented epibiont species from nesting loggerhead sea turtles (Caretta caretta) in Georgia, USA. Marine Turtle Newsletter 88:3-5.

HIRTH, H.F. 1997. Synopsis of biological data on the green turtle Chelonia mydas (Linnaeus 1758). U.S. Fish and Wildlife Service. Biological Report 97:1-120.

LIMPUS, C.J., P.J. COUPER & M.A. READ. 1994. The green turtle, Chelonia mydas, in Queensland: population structure in a warm temperate feeding area. Memoirs Queensland Museum 35(1):139-154.

LUTCAVAGE, M. & J. MUSICK. 1985. Aspects of the biology of sea turtles in Virginia. Copeia 1985:449-456.

SERAFINI, T.Z. & J.M.R. SOTO. 2000. Coral-estrela Astrangia rathbuni Vaughan, 1906 (Cnidaria, Madreporaria), epibionte em tartaruga marinha Chelonia mydas (Reptilia, Cheloniidae), no litoral do Rio Grande do Sul. Itajaí. Abstracts of XIII Semana Nacional de Oceanografia, pp. 757-758.

YOUNG, P.S. 1990. Lepadomorph cirripeds from the Brazilian coast. I - Families Lepadidae, Poecilasmatidae and Heteralepadidae. Bulletin of Marine Science 47(3):641-655.

YOUNG, P.S. 1991. The Superfamily CORONULOIDEA Leach (CIRRIPEDIA, BALANOMORPHA) from the Brazilian coast, with redescription of Stomatolepas species. Crustaceana 61(2):190-212.

YOUNG, P.S. 1999. Subclasse CIRRIPEDIA. In: L. BUCKUP & G. BOND-BUCKUP (Eds.). Os crustáceos do Rio Grande do Sul. Porto Alegre, Ed. Universidade/UFRGS. pp. 24-53.