Northern Rio de Janeiro IMMA
Size in Square Kilometres
3 910 km2
Qualifying Species and Criteria
Franciscana dolphin – Pontoporia blainvillei
Criterion A; B (1); D (1)
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Summary
This IMMA encompasses the range of an isolated and small population of the threatened franciscana dolphins (Pontoporia blainvillei) off the northern coast of Rio de Janeiro State, Brazil. The population is estimated at approximately 1,200 individuals (CV=43), and currently bycatch mortality is higher than the Potential Biological Removal level. This franciscana population is among the smallest and one of those with the most restricted distribution. Feeding and reproductive behavior of franciscana dolphins have been consistently recorded in this area. The coastal upwelling off Cape São Tomé has great relevance to ocean productivity and, therefore, to the local megafauna. Multiple records of other cetacean species such as Guiana dolphins (Sotalia guianensis), rough-toothed dolphins (Steno bredanensis), common bottlenose dolphins (Tursiops truncatus) have been documented, as well as the seasonal occurrence of baleen whales such as humpback whales (Megaptera novaeangliae) and right whales (Eubalaena australis).
Description of Qualifying Criteria
Criterion A – Species or Population Vulnerability
The franciscana is endemic to coastal waters from Brazil to Argentina. The species is currently listed as “Vulnerable” in the IUCN Red List of Threatened Species (Zerbini et al. 2017) and “Critically Endangered” nationally in Brazil (MMA/ICMBio 2022). The Potential Biological Removal level for the population in Franciscana Management Area (FMA) Ib was set as 2 or 8 individuals (depending on the Recovery Factor applied). This is interpreted as indicating that the current level of human-induced annual mortality (IBJ, 2020) risks further depleting this isolated dolphin population (Danilewicz et al., 2020).
Criterion B: Distribution and Abundance
Sub-criterion B1: Small and Resident Populations
Multiple lines of evidence suggest that the franciscana population inhabiting this area is geographically and demographically isolated and resident (Secchi et al., 2022). Abundance, corrected to account for visibility and group size bias, was estimated at 1,280 franciscanas in 2017 (CV=0.43, 95% CI: 566-2,445) (Danilewicz et al. 2020). Aerial surveys indicate that franciscanas range to maximum distance from the coast of only 16 and 28 km south and north of Cape São Tomé, respectively, result in an estimated area of occurrence of 4,000km2;. Because of the isolation and year-round residency, the entire reproductive cycle of FMA 1b franciscanas occurs within the IMMA (Di Beneditto & Ramos, 2001; Danilewicz et al., 2022). The dolphins also feed within the IMMA (Di Beneditto & Ramos, 2001; Bittar & Di Beneditto, 2009).
Criterion D: Special Attributes
Sub-criterion D1: Distinctiveness
Based on the available mitochondrial and nuclear DNA data 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 and conservation of the species by the International Whaling Commission (IWC in press). The northern coast of Rio de Janeiro corresponds to the range of a geographically, demographically, and genetically isolated population distinct from all the others (Siciliano et al. 2002, Danilewicz et al. 2020, Cunha et al., 2014, Nara et al. 2022). Moreover, the FMA1a and 1b dolphins together are considered to comprise an Evolutionarily Significant Unit (Cunha et al., 2014).
Supporting Information
Amaral, K. B., Danilewicz, D., Zerbini, A., Di Beneditto, A. P., Andriolo, A., Alvares, D. J., et al. (2018). Reassessment of the franciscana Pontoporia blainvillei (Gervais & d’Orbigny, 1844) distribution and niche characteristics in Brazil. J. Exp. Mar. Biol. Ecol. 508, 1–12. doi: 10.1016/j.jembe.2018.07.010
Bittar, V. T., and Di Beneditto, A. P. M. (2009). Diet and potential feeding overlap between Trichiurus lepturus (Osteichthyes: perciformes) and Pontoporia blainvillei (Mammalia: cetacea) in northern Rio de Janeiro, Brazil. Zoologia 26, 374–378.
Campos, E.D.J., Velhote, D., Silveira, I.C.A., 2000. Shelf break upwelling driven by Brazil current cyclonic meanders. Geophys. Res. Lett. 27 (6), 751–754.
Cunha, H. A., Medeiros, B. V., Barbosa, L. A., Cremer, M. J., Marigo, J., Lailson-Brito, J., et al. (2014). Population structure of the endangered franciscana dolphin (Pontoporia blainvillei): reassessing management units. PLoS One 9:e85633. doi: 10.1371/journal.pone.0085633
Danilewicz, D., Sucunza, F., Ott, P.H., Ferreira, E., Perez, M.S., Berchieri, N., Alvarez, D., Andriolo, A., Secchi, E.R., Flores, P.A.d.C., Farro, A.P., Martins, A., Zerbini, A.N., 2020. Abundance and distribution of franciscanas (Pontoporia blainvillei) in northern Rio de Janeiro (FMA Ib), Brazil. Paper SC/68B/ASI/07_rev1 presented to the IWC Scientific Committee. p. 14.
Danilewicz, D., Denuncio, P., Secchi, E.R., Tanios, G. (2022). The life history of franciscana dolphin. Pages 85-109 In: Simões-Lopes, P.C. & Cremer, M. (eds). The Franciscana Dolphin – On the edge of survival. Academic Press, 473pp.
Di Beneditto, A. P. M., and Ramos, R. M. A. (2001). Biology and conservation of the franciscana (Pontoporia blainvillei) in the north of Rio de Janeiro State, Brazil. J. Cetacean Res. Manage. 3, 185–192.
IBJ (2020). Diagnóstico da captura incidental de Toninha na Área de Manejo I (FMA I) e abordagem comunitária de medidas de mitigação. Instituto Baleia Jubarte. Relatório Final Integrado. 90pp.
Goldberg, D.W. et al. (2015). Hopper Dredging Impacts on Sea Turtles on the Northern Coast of Rio de Janeiro State, Brazil. Marine Turtle Newsletter No. 147: 16-20.
Nara, L. et al. (2022) Phylogeography of the Endangered Franciscana Dolphin: Timing and Geological Setting of the Evolution of Populations. Journal of Mammalian Evolution volume 29: 609–625.
Ott et al., (2022). Marine protected areas: Their potential for the conservation of the franciscana. Pages 403-443 In: Simões-Lopes, P.C. & Cremer, M.J. (eds). The Franciscana Dolphin – On the edge of survival. Academic Press, 473pp.
Palóczy, A., Silveira, C.A., Castro, B.M., Calado, L. (2014). Coastal upwelling off Cape São Tomé (22°S, Brazil): The supporting role of deep ocean processes. Continental Shelf Research. 89: 38-50.
Secchi, E. R., Danilewicz, D., and Ott, P. H. (2003). Applying the phylogeographic concept to identify franciscana dolphin stocks: implications to meet management objectives. J. Cetacean Res. Manage. 5, 61–68.
Secchi, E.R., Cremer, M.J., Danilewicz, D., Lailson-Brito, J., 2022. A synthesis of the ecology, human-related threats and conservation perspectives for the endangered franciscana dolphin. Front. Mar. Sci. 8, 617956. https://doi.org/10.3389/fmars.2021.617956.
Siciliano, S., Di Beneditto, A. P., and Ramos, R. M. A. (2002). A toninha, Pontoporia blainvillei (Gervais & d’Orbigny, 1844) (Mammalia, Cetacea, Pontoporiidae), nos estados do Rio de Janeiro e Espírito Santo, costa sudeste do Brasil: caracterizações dos habitats e fatores de isolamento das populações. Bol. Mus. Nac. 476, 1–15.
Silveira, I.C.A., Schmidt, A.C.K., Campos, E.J.D., Godoi, S.S., Ikeda, Y., 2000. A corrente do Brasil ao largo da costa leste brasileira. Rev. Bras. Oceanogr. 48 (2), 171–183.
Zerbini, A. N., Secchi, E., Crespo, E., Danilewicz, D., and Reeves, R. (2017). Pontoporia blainvillei (errata version published in 2018). The IUCN Red List of Threatened Species 2017: e.T17978A123792204. Available online at: https://dx.doi.org/10.2305/IUCN.UK.20173.RLTS.T17978A50371075.en. (accessed April 17, 2020).
