Size in Square Kilometres
Qualifying Species and Criteria
Franciscana – Pontoporia blainvillei
Criterion A; B (1); D(1)
Guiana dolphin – Sotalia guianensis
Criterion A; B (1)
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This IMMA encompasses important habitat of two dolphin species in Babitonga Bay, state of Santa Catarina, southern Brazil. The bay corresponds to a relatively shallow estuarine habitat surrounded by mangroves, muddy/sandy beaches, and rocky shores. The Babitonga Bay has been experiencing degradation caused by chemical pollution and the development of many harbors. A franciscana population of nearly 50 individuals inhabits this increasingly-impacted estuary year-round. This population is likely the smallest within the species range and is genetically isolated from franciscanas in the adjacent coastal habitat. Guiana dolphins are also found throughout the year within the bay and this population, estimated at less than 200 individuals, is near the southern limit of the species’ distribution.
Description of Qualifying Criteria
Criterion A – Species or Population Vulnerability
The franciscana is an endemic species to coastal waters of Brazil, Uruguay and Argentina and is listed as “Vulnerable” (VU) on the IUCN Red List of Threatened Species (Zerbini et al., 2017) and “Critically Endangered” (CR) nationally in Brazil (MMA, 2022). The population of franciscanas in Babitonga Bay is small and genetically isolated (see below).
The Guiana dolphin is endemic to the east coast of central and South America and is listed as “Near Threatened” (NT) on the IUCN Red List (Secchi et al., 2019) and “Vulnerable” (VU) nationally in Brazil (MMA, 2022). The population of Guiana dolphins in Babitonga bay is relatively small, but population connectivity is not well understood.
Criterion B: Distribution and Abundance
Sub-criterion B1: Small and Resident Populations
The franciscana population in Babitonga Bay is small (it was estimated in 2001-2003 at 48 individuals, CV = 0.3, Cremer and Simões-Lopes, 2008) and it is restricted to the Bay (Wells et al., 2022). Analysis of photo-identification data also indicates that the population has a high degree of residence (Sartori et al., 2017; Cremer et al., 2018). Because of the small range and year-round residency, feeding and the reproductive cycle of franciscanas in this region occurs within the bay. Data on movements of six satellite-tagged franciscanas inside the Babitonga Bay revealed that the animals remained in a very small portion of the bay, primarily over or near shallow interior flats and adjacent channels (Fig. 1) (Cremer & Simões-Lopes, 2008; Cremer et al., 2018). None of the tagged animals were recorded outside the bay (Wells et al., 2022).
The Guiana dolphin population was estimated in 2003 at 179 individuals (CV = 0.33) (Cremer et al., 2011) and has a high degree of residence (Hardt et al., 2010; Cremer et al., 2018). Systematic boat surveys indicate that Guiana dolphin groups aggregate in preferred habitats within Babitonga Bay (Fig. 2) (Cremer et al., 2011; Cremer et al., 2018).
Criterion D: Special Attributes
Sub-criterion D1: Distinctiveness
Based on the reviewed mitochondrial and nuclear DNA data available related to stock structure across the range of the franciscana, Cunha et al. (2020) proposed the existence of 11 Franciscana Management Areas (FMAs). These areas have been recognized as appropriate units for assessment of the species by the International Whaling Commision (IWC, in press). The Babitonga Bay population is unique because it corresponds to one of these management areas and is genetically differentiated and geographically isolated from franciscanas in adjacent coastal habitats. Franciscanas occupy a relatively limited habitat in the bay (Cremer et al., 2018) and animals instrumented with satellite transmitters remained within this habitat for the duration of their tracking (as many as six months, Wells et al., 2022). In addition, analysis of mtDNA and microsatellites revealed that franciscanas in Babitonga Bay are distinct from animals from nearby coastal habitats, and kinship analysis showed a high degree of philopatry for both males and females (Cunha et al., 2020; Nara et al., 2022).
Cremer, M.J. and Simoes-Lopes, P. 2005. The occurrence of Pontoporia blainvillei (Gervais and d’Orbigny) (Cetacea, Pontoporiidae) in an estuarine area in southern Brazil. Revista Brasileira de Zoologia 22(3), 717-23.
Cremer, M.J. and Simoes-Lopes, P. 2008. Distribution, abundance and density estimates of franciscanas, Pontoporia blainvillei (Cetacea, Pontoporiidae) in Babitonga Bay, southern Brazil. Revista Brasileira de Zoologia 25, 397-402.
Cremer, M.J., Hardt, F.A.S., Tonello Júnior, A.J. and Simões-Lopes, P.C.A. 2011. Distribution and status of the Guiana dolphin, Sotalia guianensis (Cetacea, Delphinidae) population in Babitonga bay, Southern Brazil. Zoological Studies 50, 327-337.
Cremer, M.J., Holz, A.C., Sartori, C.M., Schulze, B., Paitach, R.L. and Simões-Lopes, P.C. 2018. Behavior and ecology of endangered species living together: long-term monitoring of resident sympatric dolphin populations. pp. 477–508. In: Rossi-Santos, M.R., Charles, W. (Eds.), Advances in Marine Vertebrate Research in Latin America. Springer, http://doi.org/10.1007/978-3-319-56985-7_17.
Cunha, H. A., M. C. Gariboldi, M. Mendez, E. R. Secchi, L. R. Oliveira, P. Ott, J. P. Torres-Florez and A. P. C. Farro. 2020. Review on franciscana stock structure and Franciscana Management Areas (FMAs). Paper SC/68b/SDDNA7 presented to the International Whaling Commission’s Scientific Committee. 9 pp.
Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis. 1998. Proteção e Controle de Ecossistemas Costeiros: manguezal da Baía de Babitonga. Brasília, IBAMA, Coleção Meio Ambiente, Série Estudos Pesca, 146p. [in Portuguese].
IWC (in review). Report of the Workshop of the International Whaling Commision to finalize the review of the franciscana. 29p.
Nara, L., Cremer, M.J., Farro, A.P.C., Colosio, A.C., Barbosa, L.A., Bertozzi, C.P., Secchi, E.R., Pagliani, B., Costa-Urrutia, P., Gariboldi, M.C., Lazoski, C. and Cunha, H.A. 2022. “Phylogeography of the endangered franciscana dolphin: timing and geological setting of the evolution of populations”. Journal of Mammalian Evolution 29(3), 609-25.
Oliveira, T.M.N., Tureck, C.R., Bassfedl, J.C., Torrens, B.M.O., Faria, J.M. and Brasil, K. 2006. Integridade ambiental da Baía da Babitonga: características físico-químicas, microbiológicas e ecotoxicidade. In: M.J. Cremer, P.R.D. Morales and T.M.N. Oliveira (Eds). Diagnóstico ambiental da Baía da Babitonga. Joinville, Editora da Univille, XIV+256p. [in Portuguese].
Ott, P.H, Di Tullio, J., Prado, J.H., Danilewicz, D., Passadore, C., Failla, M., Bessega, M.I. and Rodríguez, D. 2022. Marine protected areas: their potential for the conservation of the franciscana. pp. 403-444. In P.C. Simões-Lopes and M.J. Cremer. The Franciscana Dolphin, Academic Press.
Sartori, C.M., Paitach, R.L. and Cremer, M.J. 2017. Photo-identification of franciscanas (Pontoporia blainvillei) in Babitonga Bay, Santa Catarina state, Brazil. The Journal of Cetacean Research and Management, 16, 49-55.
Secchi, E., Santos, M.C. de O. & Reeves, R. 2018. Sotalia guianensis (errata version published in 2019). The IUCN Red List of Threatened Species 2018, e.T181359A144232542. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T181359A144232542.en
Wells, R.S., Cremer, M.J., Berninsone, L.G., Albareda, D., Wilkinson, K.A., Stamper, M.A., Paitach, R.L. and Bordino, P. 2022. Tagging, ranging patterns, and behavior of franciscana dolphins (Pontoporia blainvillei) off Argentina and Brazil: Considerations for conservation. Marine Mammal Science 38(2): 571-605.
Zerbini, A.N., Secchi, E., Crespo, E., Danilewicz, D. & Reeves, R. 2017. Pontoporia blainvillei (errata version published in 2018). The IUCN Red List of Threatened Species 2017, e.T17978A123792204. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T17978A50371075.en