São Pedro and São Paulo Archipelago IMMA

Size in Square Kilometres

1 km2

Qualifying Species and Criteria

Common bottlenose dolphin – Tursiops truncatus

Criterion B(1)

Marine Mammal Diversity

Criterion D (1)

Tursiops truncatus

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The São Pedro and São Paulo Archipelago is an isolated group of barren islets located in the middle of the equatorial Atlantic Ocean around 1,000 km from the Brazilian mainland. The IMMA encompasses the waters surrounding the islands, which due to the influence of local upwellings, represent one of the rare productive areas over a vast region in the deep waters of the equatorial Atlantic Ocean. These productive waters host a very small (25 individuals) resident population of common bottlenose dolphins (Tursiops truncatus). Genetic studies have shown that this population is distinct from any other known population of common bottlenose dolphins from Brazilian waters, suggesting that they should be recognized as a distinct Management Unit. Some deep-feeding cetacean species, such as the sperm whale (Physeter macrocephalus) and Cuvier’s beaked whale (Ziphius cavirostris), have also been recorded around the archipelago.

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

A very small population of common bottlenose dolphins (Tursiops truncatus) inhabits the offshore waters surrounding São Pedro and São Paulo Archipelago. Data collected during line-transect and photo-identification surveys conducted in different seasons from 2011 to 2013, were used to estimate a population of 23 individuals (19–28, CI 95%). Multiple studies indicate that these dolphins are present throughout the year and occupy a restricted area around the archipelago have been corroborated by other studies (Moreno et al., 2009; Ott et al., 2009; Hoffmann & Freitas, 2018).  Dolphins were observed on most sampling days (>90% of surveys) across seasons (Milmann et al., 2017). They generally occupy the south-eastern portion of the archipelago at distances no greater than 1.2 km from the islands (Milmann et al., 2017). The minimum convex polygon (MCP, 95%) method revealed strong site fidelity, with movements, based on the 95% kernel density restricted to a 0.5 km2 area across seasons and a 0.99 km2 area across years (Milmann et al., 2017). Long-term fidelity of photo-identified dolphins to the area of São Pedro and São Paulo Archipelago has also been reported. Comparisons of photographs taken since 2004 yielded resighting intervals of over 9 years or some individuals (Milmann et al., 2017).

Criterion D: Special Attributes

Sub-criterion D1: Distinctiveness

Oliveira et al. (2019) found significant genetic differences between common bottlenose dolphins sampled at the São Pedro and São Paulo Archipelago and those sampled along the Brazilian coast. Results from mtDNA revealed that this small offshore population presented only two haplotypes, which are not shared with any other individual from the Brazilian coastal regions. Moreover, microsatellite data also showed a clear genetic differentiation between this offshore and other coastal Brazilian populations. Molecular data suggest that this population is part of, or was recently colonized by, migrants from a large oceanic North Atlantic population, which includes individuals from the archipelagos of Madeira and the Azores (Oliveira et al., 2019).

This genetic data in conjunction with the biogeographic location of the archipelago strongly suggest that the dolphins from São Pedro and São Paulo Archipelago are genetically isolated from other Brazilian populations (Oliveira et al., 2019). Based on these findings, Oliveira et al. (2019) proposed that this population should be considered as a distinct Management Unit in the southwestern Atlantic Ocean.

Supporting Information

Edwards, A., and Lubbock, R. 1983. Marine zoogeography of St Paul’s Rocks”. Journal of Biogeography, 10:65–72.

Hoffmann, L.S. and Freitas, T.R.O. 2018. “Os golfinhos do Arquipélago de São Pedro e São Paulo”. In  J.E.L. Oliveira, D.L. Viana, & M.A.C. Souza (eds.) Arquipélago de São Pedro e São Paulo: 20 anos de pesquisa. (pp 185-197). Recife: Via Design Publicações. [in Portuguese]. 

Koettker, A.G., Freire, A.S. and Sumida, P.Y.G. 2010. “Temporal, diel and spatial variability of decapod larvae from St Paul’s Rocks, an equatorial oceanic island of Brazil”. Journal of the Marine Biological Association of the United Kingdom, 90(6): 1227-1239. 

Macena, B.C.L. & Hazin, F.H.V. 2016. “Whale shark (Rhincodon typus) seasonal occurrence, abundance and demographic structure in the mid-equatorial Atlantic Ocean”. PLoS One 11, e0164440.

Milmann, L.C., Danilewicz, D., Baumgarten, J. and Ott, P.H. 2017. “Temporal–spatial distribution of an island-based offshore population of common bottlenose dolphins (Tursiops truncatus) in the equatorial Atlantic”. Marine Mammal Science, 33: 496-519.  

Moreno, I.B., Ott, P.H., Tavares, M., Oliveira, L.R., Danilewicz, D., Siciliano, S., and Bonnato, S. 2009. “Os cetáceos com ênfase no golfinho-nariz-de-garrafa, Tursiops truncatus (Montagu, 1821)”. In D.L. Viana, F.H.V. Hazin and M.A. Souza. (eds.) O Arquipélago de São Pedro e São Paulo: 10 anos de estação científica, Brasília. Secretaria da Comissão Interministerial para os Recursos do Mar, Brasília, Brasil. [in Portuguese]. 

Nunes, G.T., Bertrand, S., and Bugoni, L. 2018. Seabirds fighting for land: phenotypic consequences of breeding area constraints at a small remote archipelago. Scientific Reports, 8: 665. doi:10.1038/s41598-017-18808-7

Oliveira, L.R.D., Fraga, L.D., Ott, P.H., Siciliano, S., Lopes, F., Almeida, R., … and Bonatto, S.L. 2019. “Population structure, phylogeography, and genetic diversity of the common bottlenose dolphin in the tropical and subtropical southwestern Atlantic Ocean”. Journal of Mammalogy, 100(2): 564-577. 

Ott, P.H., Tavares. M, Moreno. I.B, Oliveira, L.R. and Danilewicz, D.S. 2009. “Os cetáceos do Arquipélago de São Pedro e São Paulo, Brasil”. In L.V. Mohr, J.W.A Castro, P.M.S Costa and R.J.V. Alves (eds.) Ilhas Oceânicas Brasileiras: da pesquisa ao manejo, vol. 2, pp. 283-300. Ministério do Meio Ambiente/ Secretaria de Biodiversidade e Florestas, Brasília, Brasil. [in Portuguese].

Spalding, M.D., Fox, H.E., Allen, G.R., Davidson, N., Ferdaña, Z.A., Finlayson, M., Halpern, B.S., Jorge, M.A., Lombana, A.L., Lourie, S.A., Martin, K.D., McManus, E., Molnar, J., Recchia, C.A. and Robertson, J., 2007. “Marine ecoregions of the world: a bioregionalization of coastal and shelf areas”. Bioscience 57(7): 573-583

Wingert, N., Milmann, L., Baumgarten, M., Danilewicz, D., Sazima, I., and Ott, P.H. 2021. “Relationships between common bottlenose dolphins (Tursiops truncatus) and whalesuckers (Remora australis) at a remote archipelago in the Equatorial Atlantic Ocean”. Aquatic Mammals, 47(6): 585-598. 


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