Journal of the Marine Biological Association of the United Kingdom cambridge.org/mbi Original Article Cite this article: Figueiredo GC, Goya SC, Santos MC de O (2019). Southern right whales in the South-western Atlantic Ocean: proposed criteria to identify suitable areas of use in poorly known reproductive grounds. Journal of the Marine Biological Association of the United Kingdom 1–6. https://doi.org/10.1017/ S0025315418001042 Received: 4 January 2018 Revised: 16 October 2018 Accepted: 30 October 2018 Key words: Balaenidae; Cetacea; Eubalaena australis; Southern right whale; use of area Author for correspondence: Giovanna Corrêa e Figueiredo, E-mail: gifigueiredo@gmail.com © Marine Biological Association of the United Kingdom 2019 Southern right whales in the South-western Atlantic Ocean: proposed criteria to identify suitable areas of use in poorly known reproductive grounds Giovanna Corrêa e Figueiredo 1 , Samara Cazzoli y Goya 2 and Marcos César de Oliveira Santos 1 1 Laboratório de Biologia da Conservação de Mamíferos Aquáticos, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, Brazil and 2 Laboratório de Geologia de Margens Continentais, Instituto Oceanográfico, Universidade de São Paulo, São Paulo, Brazil Abstract Urbanization and intense vessel traffic in coastal areas are obstacles for right whales when selecting breeding and calving grounds. Human activities might be the main cause for the recently observed drop in right whale sightings along the south-eastern coast of Brazil. Information concerning the biology and the activities that can potentially affect the presence of individuals along the coast are essential for management purposes, as well as for the recov- ery of the species stocks after a period of whaling pressure. This study correlated the occur- rence of right whales in the northern limit of the breeding ground in the South-western Atlantic Ocean with local geomorphology, degree of urbanization and oceanographic features to better identify suitable areas for use by these whales. The study area was divided into 14 sub-areas based on local coastal geomorphology and discharge of large rivers. The following five ranking criteria were applied to each sub-area: presence of whaling stations and whaling activity in the past; presence and activity of ports; protection from swell, coastal slope and composition of the bottom substrate. The sub-areas that offered conditions conducive to the presence of right whales received higher scores. The proposed criteria were validated by overlapping the ranking scores with the records of right whales sighted in each sub-area. In south-eastern Brazil, protected areas with sandy bottom and gentle slope were associated with more sightings of female-calf pairs. The criteria can be used as a primary diagnostic indi- cating suitable sub-areas for right whales in poorly known breeding grounds. Introduction Anthropogenic impacts on the southern right whale (Eubalaena australis) population along the western border of the South Atlantic began due to whaling, a period when thousands of whales were captured in a zone between south-eastern Brazil, Uruguay and Argentina (Ellis, 1969). Even after the enactment of species protection and prohibition against captures in the 1930s (Kenney, 2009), human activities continued to have a negative impact on E. australis populations. Along the Brazilian coast, whales are threatened by human activities such as drilling, fishing and boat traffic (Best et al., 2001; Figueiredo et al., 2017). The increase in vessel traffic is additionally responsible for noise pollution intensification, especially at low frequen- cies, which overlap the communication band for baleen whales. It may also increase the pro- duction of stress-related metabolites, which can lead to responses such as behavioural and vocal changes and habitat shifts (Rolland et al., 2012). The presence of right whales on the Brazilian coast occurs during migration to breeding and calving grounds in warmer subtropical coastal waters during winter and spring in the southern hemisphere (Lodi et al., 1996). The Brazilian coast is used by E. australis as a calving and breeding ground from the north-eastern coast, at approximately 8°S where sightings are occasional, to the southern limit of the country’s coastline at 32°S. Higher concentrations of whales along the coast of Brazil can be found on the southern portion of Santa Catarina State coast (Groch et al., 2005). Therefore, the national right whale protection area ‘Área de Proteção Ambiental da Baleia Franca’ was established in 2000 to safeguard the visiting whales in the area during their calving and breeding season. Individuals of the species are commonly reported in shallow waters inside bays along the south and the south-eastern coast of Brazil, where they remain for several days or weeks (Ellis, 1969; Lodi et al., 1996; Groch, 2001; Santos et al., 2001). Right whales are usually found in groups ranging from one to six individuals, and mother and calf pair is the most common group formation found (Lodi et al., 1996; Groch, 2001; Santos et al., 2001). Even though there are indications that the population in the southern hemisphere is reco- vering (see Best et al., 2001; Groch et al., 2005), the number of sightings of right whales along the south-eastern Brazilian coast is decreasing in possible relation to the increase in vessel traffic in the area (Figueiredo et al., 2017). https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0025315418001042 Downloaded from https://www.cambridge.org/core. 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