Demersal ichthyofauna of the inner continental shelf off Ilhéus, Bahia, Brazil

Ictiofauna demersal da plataforma continental interna ao largo de Ilhéus, Bahia, Brasil

INVENTORIES

Demersal ichthyofauna of the inner continental shelf off Ilhéus, Bahia, Brazil

Ictiofauna demersal da plataforma continental interna ao largo de Ilhéus, Bahia, Brasil

Leonardo Evangelista Moraes^I,*; Renato de Mei Romero^I; Gecely Rodrigues Alves Rocha^I; Rodrigo Leão de Moura^II

^IDepartamento de Ciências Biológicas, Universidade Estadual de Santa Cruz - UESC, Rod. Ilhéus-Itabuna, Km 16, CEP 45662-000, Ilhéus, BA, Brasil e-mails: [e-mail], [e-mail]

^IIConservation International Brasil, Programa Marinho, Rua das Palmeiras, 451, Centro, CEP 45900-000, Caravelas, BA, Brasil e-mail: [e-mail]

ABSTRACT

We present an inventory of demersal fishes from the inner continental shelf off Ilhéus, Bahia, Brazil. Three sites were sampled monthly, between March 2003 and February 2005, with standardized bottom trawls (30 minutes, 16 m depth, 22/16 mm mesh). A total of 7.857 specimens were captured, belonging to three species of Chondrichthyes and 95 species of Actinopterygii (77 genera and 40 families). The occurrence of Ampharius phrygiatus represents a southern range extension for this species, which was previously known only from the narrow coastal stretch between Guyana and Maranhão State (Brazil). The record of Synodus poeyi represents the first record of this species in Brazil and in the South Atlantic, as it was previously recorded only in the Caribbean. The general structure of the demersal fish assemblage is described and commented upon.

Keywords: demersal fishes, brazilian northeast, new records, scianidae.

RESUMO

Apresentamos aqui um inventário de peixes demersais da plataforma continental interna em frente a Ilhéus, Bahia, Brasil. Três locais foram amostrados mensalmente, entre março de 2003 e fevereiro de 2005, com arrastos de fundo padronizados (30 minutos, 16 m de profundidade, malha de 22/16 mm). Foram capturados 7,793 indivíduos pertencentes a três espécies de Chondrichthyes e 95 espécies de Actinopterygii (77 gêneros e 40 famílias). A ocorrência de Ampharius phrygiatus representa uma extensão do limite sul conhecido para essa espécie, que era conhecida de um trecho costeiro relativamente restrito, entre a Guiana e o Maranhão (Brasil). O registro de Synodus poeyi representa o primeiro registro dessa espécie no Brasil e no Atlântico Sul, uma vez que ela havia sido previamente registrada apenas no Caribe. A estrutura geral da assembléia de peixes demersais é descrita e comentada.

Palavras-chave: peixes demersais, nordeste brasileiro, novas ocorrências, sciaenidae.

Introduction

The Southern coast of Bahia State, Brazil, comprises a mosaic of habitats with high ecological relevance such as beaches, rocky and coralline reefs, mangroves and extensive soft-bottom plains. The nearly 80 km of coastline to the east of Ilhéus municipality (14º 35' S and 15º 00' S) are noteworthy due to the presence of the estuaries of the Cachoeira and Almada rivers, which introduce significant amounts of nutrients, sediments and hypossaline waters into a narrow continental shelf averaging only 18 km width (Bittencourt et al. 2000). The region was recently categorized by the Brazilian Federal Government as a priority area for coastal and marine biodiversity conservation (MMA 2002), meaning that immediate action is needed for natural resources' assessment and management.

Despite the region's relevance, its marine biodiversity is being increasingly threatened by overfishing, similarly to worldwide trends. Main fish species targeted by commercial fleets in Ilhéus belong to families Lutjanidae (snappers) and Serranidae (groupers), which are captured with hook-an-line in and near the continental slope. Among invertebrates the main targets of commercial fisheries are lobsters and penaeid shrimps, especially seabobs (Xiphopenaeus kroyeri), these latter captured with bottom trawls operated over soft bottom (Bahia Pesca 2003). Shrimp fisheries are of special concern because of the habitat damage inflicted by the trawling gear, and also because of the low selectivity of the nets, resulting in large amounts of bycatch. Besides physically damaging the bottom, the unrelieved capture of huge amounts of small fish, including many juveniles, may affect prey availability and the overall trophic structure of the coastal ecosystem, precluding the restocking of exploited populations (e.g. Alverson et al. 1994).

Inventories of demersal fishes in Northeastern Brazil are still sparse in terms of geographic coverage (e.g. Menezes et al. 2003, Nunes & Rosa 1998), none of them covering the Southern coast of Bahia State. Recent fish inventories were focused on the deeper portions of the region (Costa et al. 2000, Boeckman et al. 2001), despite the fact that Bahia State has the largest and one of the most diverse shorelines and continental shelves in the country. Basic surveys of fish diversity, such as the one presented herein, are still needed in order to fill in geographic gaps of species lists of demersal marine fishes. The two significant range extensions recorded herein, including a new record for Brazil, corroborate the notion than even basic fish inventories are still needed in several regions of the tropical Eastern South American coast.

Material and Methods

Monthly samples of demersal fishes were obtained between March 2003 and February 2005 in three sites off Ilhéus (Figure 1). Bottom trawling was carried out at 16 m depths, always with a 0.55 × 1.0 m net pulled by a 8 m/20 hp boat during 30 minutes. The net was similar to those regularly employed by commercial fisheries targeting X. kroyeri (22 mm mesh in the body/sleeve, 16 mm at the codend), recording the same assemblage that is caught and discarded by this fishery. Specimens were transported in ice and stored frozen until identification with the most current literature (Figueiredo & Menezes 1978, 1980, 2000, Menezes & Figueiredo 1980, 1985, Carpenter 2002a, b, Menezes et al. 2003, Marceniuk 2005).

Total length (mm) and weight (g) was recorded for each specimen. Vouchers were deposited at the Universidade Federal da Paraíba (UFPB) and Museu de Zoologia, Universidade de São Paulo (MZUSP). Families' listing follows the sequence adopted by Menezes et al. (2003), while species within families are presented in alphabetical order.

An Index of Relative Importance (IRI) was calculated accordingly to Pinkas et al. (1971), allowing us to rank each species in terms of its relative importance in number of individuals, frequency of occurrence and relative biomass.

Results

A total of 7.857 specimens were captured, belonging to three species of Chondrichthyes and 95 species of Actinopterygii (77 genera and 40 families, species/family ratio = 2.45). Most recorded species (78) are definitely demersal fishes, but a considerable number of pelagic species was also recorded (21). Four Actinopterygii were identified only at the level of genus (Lepophidium sp., Cynoscion sp., Stellifer sp. e Acanthurus sp.).

Perciformes (IRI = 65.7%) was the most important order, followed by Pleuronectiformes (IRI = 12.3%), Clupeiformes (IRI = 12.2%) and Tetraodontiformes (7.1%). Sciaenidae was the most abundant family, both in number of species (17), individuals (56.5%) and biomass (48.7%). Amongst the five most abundant species four were sciaenids (Table 2), and these were responsible for 50% of the expressed dominance (IRI). The third most abundant species biasing the scianids' domination pattern was a pelagic sardine (Table 1) that was probably captured during the upward and downward travel of the net.

Discussion

The relationship between the number of species and families (2.45) was slightly smaller than values recorded in similar studies of demersal fish assemblages in State of Paraíba (2.76) (Nunes & Rosa 1998) and Balneário de Atami, State of Paraná (2.69) (Godefroid et al. 2004), while being somewhat larger than that registered in a comparable study carried out in Penha, State of Santa Catarina (2.14) (Branco & Verani 2006). Thus, it remains unclear whether there are latitudinal trends in species/families ratios and their potential ecological or biogeographic significance.

The predominance of croakers (family Scianidae) in the study area was expected, as it is a prevalent pattern along the extensive soft bottom realm occurring across most of the inner Brazilian continental shelf (Vazzoler et al. 1999). The combined proximity of the coast and estuaries, low depths (16 m) and soft bottom (sandy/muddy) indeed assembles a preferred habitat for several sciaenid species (Vazzoler 1975, Rocha & Rossi-Wongtschowski 1998). Despite such wide-ranging homogeneous taxonomic structure at the level of families in soft bottom across the entire Brazilian continental shelf, the prevalent species seems to be quite variable geographically. In Rio Grande do Sul State, at 10-20 m depts, M. furnieri (Desmarest, 1823), Macrodon ancylodon (Bloch e Schneider, 1801) and Paralonchurus brasiliensis (Steindachner, 1875) are consistently dominant (Haimovici et al. 1996). On the other hand, near Penha, State of Santa Catarina, Isopisthus parvipinnis (Cuvier, 1830), P. brasiliensis and Stellifer spp. stand out in terms of their numerical dominance (Bail & Branco 2003). A similar assemblage occurs near Santos, State of São Paulo, where I. parvipinnis, M. furnieiri, P. brasiliensis, and two Stellifer species also dominate (Paiva-Filho et al. 1987, Giannini & Paiva-Filho 1990). There are fewer studies in Northeastern Brazil, but in the States of Sergipe and Alagoas M. furnieri, I. parvipinnis, Cynoscion virescens (Cuvier, 1830) and Nebris microps Cuvier, 1830 were recorded as the most abundant species (Sudent 1969), while Stellifer spp. and Larimus breviceps Cuvier, 1830 were recorded as the most abundant species in State of Paraíba (Nunes & Rosa 1998). Such differences can be influenced not only by the few dispersal impediments and latitudinal gradients in temperature, but mainly by habitat preferences related to sediment type, prey availability and water characteristics.

Pleuronectiformes ("flatfishes") represent another highly abundant group in the soft bottom habitats of the Eastern South American coast (Vazzoler 1975, Fagundes Netto & Gaelzer 1991, Rocha & Rossi-Wongtschowski 1998, Muto et al. 2000), and specific composition and dominance patterns among flatfishes also seems to vary across latitudinal and other environmental gradients (Araújo et al. 1997, Chaves & Corrêa 1998, Godefroid et al. 2004, Nunes & Rosa 1998). Relevantly though, the demersal fish assemblage recorded during the present study is highly similar to that recorded in the only other warm water/soft bottom locality that has been thoroughly sampled in Brazil (Nunes & Rosa 1998) (State of Paraíba).

The sampling gear (bottom trawls) chiefly targeted demersal fishes. Thus, records of pelagic fishes from families Carangidae, Clupeidae, Engraulidae, Pristigasteridae, Sphyraenidae and Trichiuridae are probably related to incidental captures during the upward and downward movements of the net (Fischer & Hureau 1985). A few demersal fishes that are generally associated with reefal or algal habitats were also recorded in very low abundances (<10 individuals). These include Acanthostracion quadricornis (Linnaeus, 1758), Canthigaster figueiredoi Moura & Castro, 2002, Heteropriacanthus cruentatus (Lacepède, 1801), Holocentrus adscensionis (Osbeck, 1765), Haemulon aurolineatum Cuvier, 1830, Myripristis jacobus Cuvier, 1829, Pseudupeneus maculates (Bloch, 1793) and Acanthurus coeruleus Bloch & Schneider, 1801. Such unexpected records of reef fishes indicate some level of habitat and faunal heterogeneity in the continental shelf, underestimated in the present study due to its sampling methods and spatial sampling design.

The occurrence of the catfish (Ariidae) Ampharius phrygiatus (Valenciennes, 1840) represents a southern range extension for this species, which was previously known only from the narrow coastal stretch between Guyana and State of Maranhão (Brazil), off Northern South America (Menezes et al. 2003, Marceniuk 2005). The record of the lizardfish (Synodontidae) Synodus poeyi Jordan, 1887 represents the first record of this species in Brazil and in the South Atlantic, as it was previously recorded only in the Caribbean (Carpenter 2002a). These two significant range extensions corroborate the notion than basic inventories are still needed in several regions of the tropical Eastern South American coast.

Finally, we remark that the checklist provided herein represents a quite accurate picture of the soft bottom demersal fish fauna of this important region, despite constrains regarding the completeness of the assessment. This demersal fish assemblage also corresponds to the taxonomic spectrum captured as bycatch of penaeids' commercial fisheries in the Ilhéus region. Some of the fishes recorded herein are valuable commercially important species captured by line fisheries, such as Carangoides crysos (Mitchill, 1815), Caranx latus Agassiz, 1831 and Lutjanus synagris (Linnaeus, 1758) (Cervigón et al. 1992, Carpenter 2002a, b). In all cases the captured individuals of these commercial species were immature, adding to the concerns regarding bycatch of bottom trawling, especially in or near habitats that are potentially working as nursery grounds.

Acknowledgements

We thank Naércio Aquino Menezes and Alexandre P. Marceniuk (Muzeu de Zoologia, Universidade de São Paulo) for the identification of catfishes (Ariidae). The Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) provided essential funding for the project (Process 478660/2003-0), and Fundação de Amparo à Pesquisa da Bahia (FAPESB) and Coordenadoria de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) provided scholarships to L.E.M and R.M.R.

Received: 11/06/09

Revised: 01/09/09

Accepted: 28/10/09

Appendix 1.

• ALVERSON, D.L., FREEBERG, M.H., MURAWSKI, S.A. & POPE, J. 1994. A global assessment of fisheries bycatch and discards. FAO, Rome, p. 1-233. (FAO Fisheries Technical Paper n. 339).
• ARAÚJO, F.G., CRUZ-FILHO, A.G., AZEVEDO, M.C., SANTOS, A.C.A. & FERNANDES, L.A.M. 1997. Estrutura da comunidade de peixes jovens da margem continental da Baía de Sepetiba, RJ. Acta Biol. Leopoldensia. 19(1):61-83.
• BAIL, G.C. & BRANCO, J.O. 2003. Ocorrência, abundância e diversidade da ictiofauna na pesca do camarão sete-barbas, na região de Penha, SC. Notas Téc. Facimar. 7:73-82.
• BITTENCOURT, A.C.S.P., DOMINGUEZ, J.M.L., MARTIN, L. & SILVA, I.R. 2000. Patterns of sediment dispersion coastwise the State of Bahia - Brazil. An. Acad. Bras. Cienc. 72(2):271-287.
• BOECKMAN, C.E., HAZIN, F.H.V. & HAZIN, H.G. 2001. Distribuição e abundância relativa de peixes demersais capturados na costa brasileira, entre São Luís (MA) e Cabo Frio (RJ). Bol. Tec. Cient. Cepene. 9(1):205-226.
• BRANCO, J.O. & VERANI, J.R. 2006. Análise quali-quantitativa da ictiofauna acompanhante na pesca de camarão sete-barbas, na Armação do Itapocoroy, Penha, Santa Catarina. Rev. Bras. Biol. 23(2):381-391.
• CARPENTER, K.E. 2002a. The living marine resources of the Western Central Atlantic. In FAO Species Identification Guide for Fishery Purposes and American Society of Ichthyologists and Herpetologists. FAO, Rome, p. 601-1374. (v. 2, part 1, special publication n. 5).
• CARPENTER, K.E. 2002b. The living marine resources of the Western Central Atlantic. In FAO Species Identification Guide for Fishery Purposes and American Society of Ichthyologists and Herpetologists. FAO, Rome, p. 1375-2127 (v. 3, part 2, special publication n. 5).
• CERVIGÓN, F., CIPRIANI, R., FISCHER, W., GARIBALDI, L., HENDRICKX, M., LEMUS, A.J., MÁRQUEZ, R., POUTIERS, J.M., ROBAINA, G. & RODRIGUEZ, B. 1992. Fichas FAO de identificación de especies para los fines de la pesca: guía de campo de las especies comerciales marinas y de aquas salobres de la costa septentrional de Sur América. FAO, Rome, p. 1-513.
• CHAVES, P.T.C. & CORRÊA, M.F.M. 1998. Composição ictiofaunística da área de manguezal da Baía de Guaratuba, Paraná, Brasil. Rev. Bras. Zool. 15(1):195-202.
• COSTA, P.A.S., MARTINS, A.S., SILVA, G.O.M., BRAGA, A.C. & HAIMOVICI, M. 2000. Prospecção pesqueira demersal no talude da costa central brasileira a bordo do N.O.Thalassa. (Campanha Bahia-2, Programa REVIZEE).
• FAGUNDES-NETO, E.B. & GAELZER. L.R. 1991. Associação de peixes bentônicos e demersais na região do Cabo Frio, RJ, Brasil. Neritica. 112:139-156.
• FIGUEIREDO, J.L. & MENEZES N.A. 1978. Manual dos peixes marinhos do Sudeste do Brasil. II. Teleostei (1). Universidade de São Paulo, São Paulo.
• FIGUEIREDO, J.L. & MENEZES N.A. 1980. Manual dos peixes marinhos do Sudeste do Brasil. III. Teleostei (2). Universidade de São Paulo, São Paulo.
• FIGUEIREDO, J.L. & MENEZES N.A. 2000. Manual dos peixes marinhos do Sudeste do Brasil. VI. Teleostei (5). Universidade de São Paulo, São Paulo.
• FISCHER, W. & HUREAU, J.C. 1985. FAO species identification sheets for fishery purposes. southern ocean: fishing areas 48, 58 and 88. FAO, Rome. (CCAMLR convention area, v. 2).
• GIANNINI, R. & PAIVA-FILHO, A.M. 1990. Os sciaenidae (Teleostei: Perciformes) da Baía de Santos (SP), Brasil. Bolm. Inst. Oceanogr. 38(1):69-86.
• GODEFROID, R.S., SPACH, H.L., SANTOS, C., MACLAREN, G. & SCHWARZ Jr., R. 2004. Mudanças temporais na abundância e diversidade da fauna de peixes do infralitoral raso de uma praia, sul do Brasil. Iheringia, Sér. Zool. 94(1):95-104.
• HAIMOVICI, M., MARTINS, A.S. & VIEIRA, J.P. 1996. Distribuição e abundância de peixes teleósteos demersais sobre a plataforma continental do sul do Brasil. Rev. Brasil. Biol. 56(1):27-50.
• Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis - IBAMA. 2003. Boletim estatístico da pesca marítima e estuarina: ano 2002. Secretaria de Agricultura, Irrigação e Reforma Agrária, Salvador, p. 1-25.
• MARCENIUK, A.P. 2005. Chave de identificação das espécies de bagres marinhos (Siluriformes, Ariidae) da costa brasileira. B. Inst. Pesca. 31(2):89-101.
• MENEZES, N.A., BUCKUP, P.A., FIGUEIREDO, J.L. & MOURA, R.L. 2003. Catálogo das espécies de peixes marinhos do Brasil. Universidade de São Paulo, São Paulo.
• MENEZES, N.A. & FIGUEIREDO, J.L. 1980. Manual de peixes marinhos do Sudeste do Brasil. IV. Teleostei (3). Universidade de São Paulo, São Paulo.
• MENEZES, N.A. & FIGUEIREDO, J.L. 1985. Manual de peixes marinhos do Sudeste do Brasil. V. Teleostei (4). Universidade de São Paulo, São Paulo.
• Ministério do Meio Ambiente - MMA. 2002. Avaliação e ações prioritárias para a conservação da biodiversidade das zonas costeira e marinha. MMA, Brasília.
• MUTO, E.Y., SOARES, L.S.H. & ROSSI-WONGTSCHOWSKI, C.L.D.B. Demersal fish assemblages off São Sebastião, southeastern Brazil: Structure and environmental conditioning factors (Summer, 1994). Rev. Bras. Oceanogr. 48(1):9-27, 2000.
• NUNES, C.R.R. & ROSA, R.S. 1998. Composição e distribuição da ictiofauna acompanhante em arrastos de camarão na costa da Paraíba, Brasil. Trab. Oceanog. 26(2):67-83.
• PAIVA-FILHO, A.M., GIANNINI, R., RIBEIRO-NETO, F.B. & SCHMIEGELOW, J.M.M. 1987. Ictiofauna do complexo Baía-Estuário de Santos e São Vicente, SP, Brasil. Relat. Int. Inst. Oceanogr. 17:1-10.
• PINKAS, L., OLIPHANT, M.S. & IIVERSON, I.L.K. 1971. Food habits of albacore, bluefin tuna, and bonito in California waters. Fish. Bull. 152:1-105.
• ROCHA, G.R.A. & ROSSI-WONGTSCHOWSKI, C.L.D.B. 1998. Demersal fish community on the inner shelf of Ubatuba, southeastern Brazil. Rev. Bras. Oceanogr. 46(2):93-109.
• Superintendência do Desenvolvimento do Nordeste - SUDENE. 1969. Departamento de recursos naturais. Docum. Pesca. 19:1-48. (Projeto Akarôa).
• VAZZOLER, G. 1975. Distribuição da fauna de peixes demersais e ecologia dos Sciaenidae da plataforma continental brasileira entre as latitudes 29ş21'S (Tôrres) e 33ş41'S (Chuí). Bolm. Inst. Oceanogr. 24:85-169.
• VAZZOLER, A.E.M., SOARES, L.S.H. & CUNNINGHAM, P.M. 1999. Ictiofauna da Costa brasileira. In Estudos ecológicos de comunidades de peixes tropicais (R. C. Lowe McConnell, ed.). Editora da Universidade de São Paulo, São Paulo, p. 424-467.

Publication Dates

• Publication in this collection
  26 Mar 2010
• Date of issue
  Dec 2009

History

• Accepted
  28 Oct 2009
• Reviewed
  01 Sept 2009
• Received
  11 June 2009