Guanabara-Sepetiba Coastal Embayment Complex IMMA

Size in Square Kilometres

980 km2

Qualifying Species and Criteria

Guiana dolphin – Sotalia guianensis

Criterion A; B (1,2); C (1,2)

Rough-toothed dolphin – Steno bredanensis

Criterion C (2)

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The Guanabara-Sepetiba Coastal Embayment Complex IMMA includes two coastal bays with estuarine characteristics and rich ecosystem environments including sand beaches, rocky shores, mangroves, islands, and rivers. These areas share similar characteristics that are suitable for the residency and survival of the nationally “Vulnerable” and globally “Near Threatened” Guiana dolphins (Sotalia guianensis). Rough-toothed dolphins (Steno bredanensis) and bottlenose dolphins (Tursiops truncatus) are non-resident species but regularly observed feeding in Guanabara Bay. Harbor activities, heavy boat traffic, chemical and noise pollution, overfishing and bycatch are the main threats in this IMMA.  The bays comprise two marine conservation units. Although Sepetiba and Guanabara Bay are not geographically connected, movement of Guiana dolphin individuals between both environments was already reported through photo-identification efforts.

Description of Qualifying Criteria

Criterion A – Species or Population Vulnerability

Guiana dolphin (Sotalia guianensis) is classified “near threatened” by IUCN (Secchi et al., 2018) and “vulnerable” on the Brazilian Endangered Species National List (MMA/ICMBio, 2022).

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

Through a long-term mark-recapture effort using photo-identification in Guanabara Bay, Azevedo et al. (2017) reported on the first decline of a delphinid population in Brazilian waters.  The Guiana dolphin population in Guanabara Bay declined from 62 (95%CI 59 – 65) to 39 (37 – 40) representing a 63% decline in the resident population in an interval of 15 years. In Guanabara Bay, Guiana dolphins are resident and socializing and births are registered year-round (Azevedo et al. 2005, Azevedo et al. 2017).  Guiana dolphins are reported to feed between 60-80% of the time in Guanabara Bay (Azevedo et al. 2007, Ribeiro-Campos et al. 2021).

Sub-criterion B2: Aggregations

The Guiana dolphin population in Sepetiba Bay is reported as resident and aggregations of up to 200 individuals are commonly reported in that area (Flach et al., 2008; Ribeiro-Campos et al., 2021). The most recent estimate for the Guiana dolphin population in Sepetiba Bay was conducted using data from mark-recapture photo-identification efforts from 2017 to 2020 where 1,620 individuals (CI 95% 1,555 – 1,697) were estimated (Quintana, 2020).

Criterion C: Key Life Cycle Activities

Sub-criterion C1: Reproductive Areas

In Sepetiba Bay births of Guiana dolphin are observed year-round and neonates and calves are frequently reported (Flach et al. 2008, Ribeiro-Camos et al. 2021).

Sub-criterion C2: Feeding Areas

In Sepetiba bay, groups of Guiana dolphins can be seen feeding, socializing, traveling, and resting on a daily basis (Ribeiro-Campos et al. 2021; Beirão-Campos et al.  2019).

Carvalho et al. (2020) reported that feeding was the most common behavior observed for Steno bredanensis in Guanabara Bay. Main preys in this area are largehead hairtail fish  (Trichiurus lepturus), mullets (Mugil curema and Mugil liza) and cephalopods such as Loligo plei and Loligo sanpaulensis (Melo et al., 2010; Lodi and Maricato, 2020). Stable isotopic analyses showed that S. bredanensis typically an inner continental shelf predator, was in this area sharing prey species in the same ecological group as the strictly coastal resident Sotalia guianensis (Bisi et al. 2013).

The occurrence of Tursiops truncatus is seasonal, possibly associated to upwelling events in the summer (Lodi, 2016). Stomach content analyses showed that Atlantic midshipman fish (Porichtys porosissimus) and the squid (Loligo sanpaulensis) were the main preys of teleosts and cephalopods, respectively, in this area (Melo et al. 2010).

Supporting Information

Amador, E.S. 2013. Baía de Guanabara Ocupação histórica e avaliação ambiental., Ed.1, 510 p. Rio de Janeiro: Interciência

Azevedo, A. F., Viana, S. C., Oliveira, A. M., and Van Sluys, M. 2005. ‘Group characteristics of marine tucuxis (Sotalia fluviatilis)(Cetacea: Delphinidae) in Guanabara Bay, south-eastern Brazil’. Journal of the Marine Biological Association of the United Kingdom, 85: 209-212.

Azevedo, Alexandre F., Oliveira, A.M., Viana, S.C., and Van Sluys, M. 2007. ‘Habitat use by marine tucuxis (Sotalia guianensis) (Cetacea: Delphinidae) in Guanabara Bay, south-eastern Brazil’. Journal of the Marine Biological Association of the United Kingdom, 87: 201.

Azevedo, A.F., Carvalho, R.R., Kajin, M., Van Sluys, M., Bisi, T.L., Cunha, H.A. and Lailson-Brito, J. 2017. The first confirmed decline of a delphinid population from Brazilian waters: 2000-2015 abundance of Sotalia guianensis in Guanabara Bay, South-eastern Brazil. ECOLOGICAL INDICATORS, 79: 1-10.

Beirão-Campos, L., Cantor, M., Flach, L., and Simões-Lopes, P. C. 2016. ‘Guiana dolphins form social modules in a large population with high ranging overlap and small demographic changes’. Behavioral ecology and sociobiology, 70: 1821-1830.

Bisi, T., Dorneles, P. R., Lailson-Brito, J., Lepoint G., Azevedo A. F., Flach L., Malm O. and Krishna, D. 2013. ‘Trophic relationships and habitat preferences of delphinids from the southeastern Brazilian coast determined by carbon and nitrogen stable isotope composition’. Plos One, 8: 8-15.

Bittencourt, L., Lima, I.M.S., Andreade, Luciana G., Carvalho, R.R., Bisi, T.L., Lailson-Brito, J., and Azevedo, A.F. 2016. ‘Underwater noise in an impacted environment can affect Guiana dolphin communication’. Marine Pollution Bulletin, 114: 1130-1134.

Carvalho, R.R., Lailson-Brito, J., Kajin M., Quintana, C.E.P., Pereria, K.S., Bisi, T.L., Cunha, H.A. and Azevedo, A.F. 2020. ‘Shallow-water habitat use and population parameters of rough-toothed dolphins, Steno bredanensis (G. Cuvier in Lesson, 1828) in southeastern Brazil’. Marine Mammal Science, 1-16.

Copeland, G., Monteiro, T., Couch, S. and Borthwick, A. 2003. Water quality in Sepetiba Bay, Brazil. Marine Environmental Research 55, 385–408.CrossRefGoogle ScholarPubMed

Domit, C. 2010. ‘Ecologia comportamental do boto-cinza, Sotalia guianensis (van Bénéden, 1864), no estado do Paraná, Brasil’. Tese, Universidade Federal do Paraná. 

Domit, C., Caballero, S., Miranda, A.V., Fruet, P., Torres-Florez, J.P., Cunha, H.A., Farro, A.P., Azevedo, A.F., Bisi, T., Briseno, Y., Cremer, M.J., Tardin, R., Barreto, A.S., Bertozzi, C.P., Laislson-Brito, J., Barrios-Garrido, H., Belleghen, T.V., May-Collado, L.J., Tullio, J., Bracarense, A.P., Cantor, M., and Andriolo, A. 2021. Report of the Sotalia guianensis Pre-Assessment Workshop: Main Results and Status of Current Knowledge. THE JOURNAL OF CETACEAN RESEARCH AND MANAGEMENT, 22: 333-378.

Flach, L., Flach, P.A., and Chiarello, A.G., 2008. ‘Aspects of behavioral ecology of Sotalia guianensis in Sepetiba Bay, southeast Brazil’. Marine Mammal Science, 24: 503–515.

Kjerfve, B., Lacerda, L.D., Dias, G.T.M. 2001. ‘Baía de Guanabara, Rio De Janeiro, Brazil’. In: Coastal Marine Ecosystems of Latin America. pp. 107–117.

Lailson-Brito, J., Dorneles, P.R., Azevedo-Silva, A.F., Azevedo, A.F., Vidal, L.G., Zanelatto, R.C., Lozinski, C.P.C., Azeredo, A., Fragoso, A.B.L., Cunha, H.A., Torres, J.P.M. and Malm, O. 2010. ‘High organochlorine accumulation in blubber of Guiana dolphin, Sotalia guianensis, from Brazilian coast and its use to establish geographical differences among populations. Environmental Pollution, 158: 1800-1808. DOI: 10.1016/j.envpol.2009.11.002.

Lodi L. 2016. ‘Update on the current occurrence of Tursiops truncatus (Montagu, 1821) in Rio de Janeiro State’. The Latin American Journal of Aquatic Mammals, 11: 220-226.

Lodi, L. and Maricato, G. 2020. ‘Rough-toothed dolphins (Cetartiodactyla: Delphinidae) habitat use in coastal urban waters of the Sotuh-western Atlantic’. Journal of the Biologica Association of the United Kingdom, 1: 1-9.

Melo, C. L. C., Santos, R. A., Bassoi, M., Araújo, A. C., Lailson-Brito, J., Dorneles, P. R. and Azevedo, A. F. 2010. ‘Feeding habits of delphinids (Mammalia: Cetacea) from Rio de Janeiro State, Brazil’. Journal of the Marine Biological Association of the United Kingdom, 90: 1509–1515.

MMA/ICMBio. 2022. Lista Nacional de Espécies Ameaçadas. Ministério do Meio Ambiente. Available at: (Accessed in: 12 June 2022).

Quintana, C.E.P. 2020. Parâmetros populacionais, fidelidade de sítio e movimentação do boto-cinza (Sotalia guianensis) (Van Bénéden, 1864) (Cetartiodactyla, Delphinidae) nas baías da Ilha Grande (RJ) e Sepetiba (RJ). Master thesis.

Ribeiro-Campos, A., Pereira, K.S., Quintana, C.E.P., Barbosa, M., Dias, C.P., Briao, J.A.,…and Azevedo, A.F. 2021. ‘Habitat use by the Guiana dolphin (Sotalia guianensis)(Cetartiodactyla: Delphinidae) in southeastern Brazil’. Regional Studies in Marine Science, 44, 101778. 

Santos, M.C.O., Laílson-Brito, J., Flach, L., Oshima, J.E., Figueiredo, G.C., Carvalho, R.R. and Azevedo, A.F. 2019. Cetacean movements in coastal waters of the southwestern Atlantic ocean. Biota Neotropica, 19.

SEMADS, 2001. Ambiente das águas do Estado do Rio de Janeiro. Rio de Janeiro.

Secchi, E., Santos, M.C.O., and Reeves, R. 2018. ‘Sotalia guianensis (errata version published in 2019)’. The IUCN Red List of Threatened Species 2018: e.T181359A144232542.

Signorini, S.R., 1980. ‘A study of the circulation in Bay of Ilha Grande and Bay of Sepetiba: part I. a survey of the circulation based on experimental field data’. Boletim do Instituto Oceanográfico. 29: 41–55.


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