Predicting the breeding hotspots of the southern right whale, Eubalaena australis (Cetartiodactyla: Mysticeti), along the southern Brazilian coastline

INTRODUCTION

Migratory baleen whales have an extensive ecological niche, and the environmental conditions that define this niche are extremely diverse. Baleen whales usually migrate seasonally between feeding and calving grounds (Corkeron and Connor 1999Corkeron P.J., Connor R.C. 1999. Why do baleen whales migrate? Mar. Mamm. Sci. 15: 1228-1245. https://doi.org/10.1111/j.1748-7692.1999.tb00887.x ). The southern right whale, Eubalaena australis (Desmoulins, 1822), is a baleen whale that lives in the southwest Atlantic Ocean, breeds in Argentina and Brazil in winter and spring (Rowntree et al. 2001Rowntree V.J., Payne R.S., Schell D.M. 2001. Changing patterns of habitat use by southern right whales (Eubalaena australis) on their nursery ground at Península Valdés, Argentina, and their long-range movements. J. Cetacean Res. Manag. 2(Special Issue): 133-143. https://doi.org/10.47536/jcrm.vi.298 ) and feeds around the South Georgia Islands in summer and autumn (Zerbini et al. 2017Zerbini AN., Fernandez A., Andriolo A., et al. 2017. Satellite tracking of Southern right whales Eubalaena australis from Golfo San Matías, Rio Negro Province, Argentina. Rep. IWC. SC/67B/CMP/17.). Another species, the humpback whale, Megaptera novaeanglia (Borowski, 1781), breeds in northeastern Brazilian coastal areas and has also been tracked to the South Georgia Islands for feeding (Zerbini et al. 2006Zerbini A.N., Andriolo A., Heide-Jorgensen M.P., et al. 2006. Satellite-monitored movements of humpback whales Megaptera novaeangliae in the Southwest Atlantic Ocean. Mar. Ecol. Prog. Ser. 313: 295-304. https://doi.org/10.3354/meps313295 ). This information shows the large gradient that defines this species’ ecological niche, because environmental conditions between these two regions, such as sea surface temperature, are substantially different.

Recently, studies that predict the distribution patterns of animals have increased, as these patterns provide basic information to determine management and conservation strategies. Habitat modelling approaches are frequently used and show effective results in predicting cetacean distribution (Redfern et al. 2006Redfern J.V., Ferguson M.C., Becker E.A., et al. 2006. Techniques for cetacean-habitat modeling. Mar. Ecol. Prog. Ser. 310: 71-295. https://doi.org/10.3354/meps310271 ), including that of baleen whales. Regression models, such as generalized additive models and linear models, have been effectively used to understand species distribution patterns. However, for these models to be effective and produce unbiased results, the data must be obtained with several, well-delimited standard protocols. When data do not follow these assumptions or when presence-only data are available (i.e. repository, opportunistic and collection data), other methods such as maximum entropy are more appropriate (Elith et al. 2011Elith J., Phillips S.J., Hastie T., et al. 2011. A statistical explanation of MaxEnt for ecologists. Diversity Distrib. 17: 43-57. https://doi.org/10.1111/j.1472-4642.2010.00725.x ). In studies on migratory baleen whales, the ecological conditions for predicting their distribution in feeding areas are different from those for breeding and calving areas (Redfern et al. 2006Redfern J.V., Ferguson M.C., Becker E.A., et al. 2006. Techniques for cetacean-habitat modeling. Mar. Ecol. Prog. Ser. 310: 71-295. https://doi.org/10.3354/meps310271 ). Whale distribution in feeding areas is mainly defined by prey distribution (Friedler et al. 2006). In breeding areas, whales fast, and their distribution may be related to areas that increase calf survival.

The southern right whale is a migratory baleen whale that breeds along the Brazilian coast (Palazzo and Carter 1983Palazzo J.T., Carter L.A. 1983. A caça de baleias no Brasil. Agapan, Porto Alegre, 25 pp., Lodi et al. 1996Lodi L., Siciliano S., Bellini C. 1996. Ocorrência e conservação de baleias-francas-do-sul, Eubalaena australis, no litoral do Brasil. Papeis Avulsos de Zoologia 3917: 307-328.). Because of whaling activity on the Brazilian coast from 1602 to 1976 (Morais et al. 2017Morais I.O.B., Danilewicz D., Zerbini N.A., Bortolotto G.A. 2017. From the southern right whale hunting decline to the humpback whaling expansion: a review of whale catch records in the tropical western South Atlantic Ocean. Mammal Rev. 47: 11-23. https://doi.org/10.1111/mam.12073 ), the species occurrence is currently reduced. It is distributed mainly along the Santa Catarina state coast, with sporadic records in the southeastern and northeastern Brazilian coasts (Ellis 1969Ellis M. 1969. A baleia no Brasil colonial. Melhoramentos, São Paulo/SP., Figueiredo et al. 2017Figueiredo G.C., Santos C.O.M., Siciliano S., Moura J.F. 2017. Southern right whales Eubalaena australis in an urbanized area off the southwestern Atlantic Ocean: updated records and conservation issues. Aquat. Mamm. 43: 52-62. https://doi.org/10.1578/AM.43.1.2017.52 , Morais et al. 2017Morais I.O.B., Danilewicz D., Zerbini N.A., Bortolotto G.A. 2017. From the southern right whale hunting decline to the humpback whaling expansion: a review of whale catch records in the tropical western South Atlantic Ocean. Mammal Rev. 47: 11-23. https://doi.org/10.1111/mam.12073 ).

Several bays have shown a higher whale density than that shown in records from previous research, which appears to be linked to the current population growth rate (Groch et al. 2005Groch K.R., Palazzo Jr. JT., Flores P.A., et al. 2005. Recent rapid increases in the right whale Eubalaena australis population off southern Brazil. Lat. Am. J. Aquat. Mamm. (LAJAM) 4: 41-47. https://doi.org/10.5597/lajam00068 , Renault-Braga et al. 2018Renault-Braga E.P., Groch K.R., Flores P.A.C., et al. 2018. Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales, Eubalaena australis, in southern Brazil. Mar. Ecol. (Berl). 39: e12506. https://doi.org/10.1111/maec.12506 , Renault-Braga, et al. 2021aRenault-Braga E.P., Groch K.R., Simões-Lopes P.C. 2021a. Numerical population estimates update for Southern Right Whales in Brazil. Rep. IWC. SC/68C/CMP.). Therefore, some regions where species occurrence is frequent may reach the carrying capacity in a few years, which would force some whales to search for other areas with similar oceanographic conditions relatively soon. Predicting these potential areas will allow us to conduct research and conservation programmes.

Therefore, our objective was to predict future potential occupation areas (here, potential breeding hotspots) of right whales in Brazil, using habitat modelling approaches and a 16-year dataset of southern right whale occurrences.

MATERIALS AND METHODS

Study area

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To predict the right whale breeding hotspots, we delimited the southern Brazilian coast, which includes three states (Paraná, Santa Catarina and Rio Grande do Sul) (25.0319°S to 33.727°S). We delimited this area because it is the boundary of the major occurrence areas for the species (Renault-Braga et al. 2018Renault-Braga E.P., Groch K.R., Flores P.A.C., et al. 2018. Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales, Eubalaena australis, in southern Brazil. Mar. Ecol. (Berl). 39: e12506. https://doi.org/10.1111/maec.12506 ). A 20-km buffer from the coastline was created using ArcMap 10.4 (ESRI). This resulted in a total analysed area of 23027 km², which was the region where potential hotspots were predicted (Fig. 1).

Fig. 1.  Study area with the 11 federal management units along the southern coast of Brazil. Red polygons represent the managements units. The white polygon represents the area where the hotspots will be predicted.

RESULTS

Southern right whale sight data

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The dataset contained 3010 records from systematic aerial surveys, 16 records from SIMMAM and 2 records from PMC-BS. After data sorting, we used 528 records of southern right whales to run our models, of which 110 were unaccompanied adults and 418 were mother-calf pairs (Fig. 2).

Fig. 2.  Dataset of southern right whales’ presence in the study area in southern Brazil after data sorting (110 unaccompanied adults and 418 mother-calf pairs).

Unaccompanied adults

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All four variables were used in the model and demonstrated good accuracy (AUC=0.974±0.004) (Fig. 3A). The prediction of the hotspot map showed a coastal preference along most of the coastline and some coastal islands (Fig. 4).

Fig. 3.  ROC curve of the average model to predict breeding hotspots of unaccompanied adults (A) and mother-calf pairs (B) of southern right whales in southern Brazil. This curve generates an AUC of 0.971(±0.004) for unaccompanied whales and 0.958(±0.012) for mother-calf pairs.

Fig. 4.  Predicted hotspots of unaccompanied adults of southern right whales along the southern Brazilian coast.

Coastal distance, slope and coastal linearity were the variables that most contributed to the model for unaccompanied adults, at 54%, 24.5%, and 19.3%, respectively. Substrate type was the variable that least contributed to the model (2.2%). However, the jackknife test showed that the absence of any of the variables decreased the AUC value of the model (Fig. 5A).

Fig. 5.  Jackknife test of the model for unaccompanied adults (A) and mother-calf pairs (B) of right whales in southern Brazil. Coast distance showed 54% of model contribution, coast linearity 19.3%, slope 24.5% and substrate type 2.2% for unaccompanied adults. Coast linearity showed 82% of model contribution, slope 11.6%, coast distance 4.6% and substrate type 1.7% for mother-calf pairs.

Mother-calf pairs

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All four variables were used in the model and demonstrated good accuracy (AUC=0.958±0.012) (Fig. 3B). The prediction map generated by the model indicated potential hotspots along all coastal areas of the delimited study polygon, but with an occurrence closer to the coast than in the results obtained for the unaccompanied adults (Fig. 6).

Fig. 6.  Predicted hotspots of mother-calf pairs of southern right whales along the southern Brazilian coast.

Coastal linearity showed the highest contribution (82%) to the model, followed by slope (11.6%), coastal distance (4.6%) and substrate type (1.7%). As described for the unaccompanied adults, the jackknife test showed that the absence of any of the variables decreased the AUC value of the model (Fig. 5B).

DISCUSSION

Historically, southern right whales have existed in Brazil from the south of Bahia State (12.993°S) to the Rio Grande do Sul State (33.743°S) (Lodi et al. 1996Lodi L., Siciliano S., Bellini C. 1996. Ocorrência e conservação de baleias-francas-do-sul, Eubalaena australis, no litoral do Brasil. Papeis Avulsos de Zoologia 3917: 307-328.). Currently, distribution is limited to southern Brazil, mainly in Santa Catarina state, with sporadic sightings near the north- and southeastern coasts (Lodi et al. 1996Lodi L., Siciliano S., Bellini C. 1996. Ocorrência e conservação de baleias-francas-do-sul, Eubalaena australis, no litoral do Brasil. Papeis Avulsos de Zoologia 3917: 307-328., Figueiredo et al. 2017Figueiredo G.C., Santos C.O.M., Siciliano S., Moura J.F. 2017. Southern right whales Eubalaena australis in an urbanized area off the southwestern Atlantic Ocean: updated records and conservation issues. Aquat. Mamm. 43: 52-62. https://doi.org/10.1578/AM.43.1.2017.52 , Renault-Braga et al. 2018Renault-Braga E.P., Groch K.R., Flores P.A.C., et al. 2018. Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales, Eubalaena australis, in southern Brazil. Mar. Ecol. (Berl). 39: e12506. https://doi.org/10.1111/maec.12506 ). Previous studies have modelled factors that influence right whale distribution in Brazilian breeding grounds (Seyboth et al. 2015Seyboth E., Groch K.R., Secchi E.R., Dalla-Rosa L. 2015. Habitat use by southern right whales, Eubalaena australis Desmoulins, 1822, in their main northern calving area in the western South Atlantic. Mar. Mamm. Sci. 314: 1521-1537. https://doi.org/10.1111/mms.12241 ), but this is the first study to predict potential breeding hotspots.

Maxent, a “presence-only” model, allowed us to use a dataset of southern right whale sightings that also includes oceanic and neritic areas, even though coastal distribution in the breeding area is a pattern already observed in other breeding grounds (Best 1990Best P.B. 1990. Trends in the inshore right whale population off South Africa, 1969-1987. Mar. Mamm. Sci. 6: 93-108. https://doi.org/10.1111/j.1748-7692.1990.tb00232.x , Danilewicz et al. 2016Danilewicz D., Moreno IB., Tavares M., Sucunza F. 2016. Southern right whales (Eubalaena australis) off Torres, Brazil: group characteristics, movements, and insights into the role of the Brazilian-Uruguayan wintering ground. Mammalia 81: 1-10. https://doi.org/10.1515/mammalia-2015-0096 ). However, the limited records regarding oceanic areas may be sporadic or represent whales on migratory routes (Zerbini et al. 2017Zerbini AN., Fernandez A., Andriolo A., et al. 2017. Satellite tracking of Southern right whales Eubalaena australis from Golfo San Matías, Rio Negro Province, Argentina. Rep. IWC. SC/67B/CMP/17.).

The model prediction did not reveal any unsuitable areas along the entire coastal region of the study area (Figs 5 and 6). Currently, stranding events and sightings confirm the occurrence of right whales in Paraná (Instituto Australis, unpublished data) and Rio Grande do Sul (Danilewicz et al. 2016Danilewicz D., Moreno IB., Tavares M., Sucunza F. 2016. Southern right whales (Eubalaena australis) off Torres, Brazil: group characteristics, movements, and insights into the role of the Brazilian-Uruguayan wintering ground. Mammalia 81: 1-10. https://doi.org/10.1515/mammalia-2015-0096 , Greig et al. 2001Greig A.B., Secchi E.R., Zerbini A.N., Dalla Rosa L. 2001. Stranding events of southern right whales, Eubalaena australis, in southern Brazil. J. Cetacean Res. Manag. 2: 157-160.). The factors influencing whale preferences for Santa Catarina over Paraná and Rio Grande do Sul are unknown. For mother-calf pairs, sheltered areas can be advantageous for calf development, as well as for mothers who fast during the breeding season to save energy (Payne 1986Payne R. 1986. Long-term behavioral studies of the southern right whale Eubalaena australis. Rep. IWC. 10 (Special Issue): 161-168.). This may explain the preference for Santa Catarina over Rio Grande do Sul. Santa Catarina has an irregular coastline forming several bays that may confer protection against wind and waves, whereas Rio Grande do Sul and Paraná have a straight coastline. The seasonality of the species on the southern coast of Santa Catarina is well documented (Groch 2005Groch K.R. 2005. Biologia populacional e ecologia comportamental da Baleia Franca Austral, Eubalaena australis Desmoulins, 1822, CETACEA, MYSTICETI, no litoral do Brasil. PhD thesis, Univ. Fed. do Rio Grande do Sul, 169 pp., Seyboth et al. 2015Seyboth E., Groch K.R., Secchi E.R., Dalla-Rosa L. 2015. Habitat use by southern right whales, Eubalaena australis Desmoulins, 1822, in their main northern calving area in the western South Atlantic. Mar. Mamm. Sci. 314: 1521-1537. https://doi.org/10.1111/mms.12241 , Renault-Braga et al. 2018Renault-Braga E.P., Groch K.R., Flores P.A.C., et al. 2018. Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales, Eubalaena australis, in southern Brazil. Mar. Ecol. (Berl). 39: e12506. https://doi.org/10.1111/maec.12506 ), whereas from Florianópolis to the north, its occurrence is sporadic but more prevalent than in Paraná and Rio Grande do Sul.

Whaling in Brazil collapsed the right whale population in the 19^th century (Morais et al. 2017Morais I.O.B., Danilewicz D., Zerbini N.A., Bortolotto G.A. 2017. From the southern right whale hunting decline to the humpback whaling expansion: a review of whale catch records in the tropical western South Atlantic Ocean. Mammal Rev. 47: 11-23. https://doi.org/10.1111/mam.12073 ). The last whaling station in Santa Catarina was closed in 1829 (Ellis 1969Ellis M. 1969. A baleia no Brasil colonial. Melhoramentos, São Paulo/SP.), and in the 1950s, when the population had shown some recovery, whaling was reinstated until 1973, when the last right whale was captured in Brazil (Palazzo and Carter 1983Palazzo J.T., Carter L.A. 1983. A caça de baleias no Brasil. Agapan, Porto Alegre, 25 pp.). Whaling has been officially illegal in Brazil since 1986, and since then, the population has shown some recovery. Right whales show some philopatry to their breeding grounds (Rowntree et al. 2001Rowntree V.J., Payne R.S., Schell D.M. 2001. Changing patterns of habitat use by southern right whales (Eubalaena australis) on their nursery ground at Península Valdés, Argentina, and their long-range movements. J. Cetacean Res. Manag. 2(Special Issue): 133-143. https://doi.org/10.47536/jcrm.vi.298 , Groch et al. 2005Groch K.R., Palazzo Jr. JT., Flores P.A., et al. 2005. Recent rapid increases in the right whale Eubalaena australis population off southern Brazil. Lat. Am. J. Aquat. Mamm. (LAJAM) 4: 41-47. https://doi.org/10.5597/lajam00068 ), which appears to be transferred by the mother to the calf (Valenzuella et al. 2009Valenzuella L.O., Sironi M., Rowntree V.J., Seger J. 2009. Isotopic and genetic evidence for culturally inherited site fidelity to feeding grounds in southern right whales (Eubalaena australis). Mol. Ecol. 18: 782-791. https://doi.org/10.1111/j.1365-294X.2008.04069.x ). The greater occurrence of right whales between Florianópolis (27.768°S) and Torres (29.367°S) may be related to philopatry of the breeding grounds. It is possible that social information (Oro 2020Oro D. 2020. Perturbation, behavioural feedbacks, and population dynamics in social animals: when to leave and where to go. Oxford University Press, Oxford, 176 pp. https://doi.org/10.1093/oso/9780198849834.001.0001 ) regarding the use of areas different from Santa Catarina was lost or severely reduced owing to intense whaling in other regions. However, the recent recovery that has been noted in the Brazilian breeding population (Renault-Braga et al. 2021aRenault-Braga E.P., Groch K.R., Simões-Lopes P.C. 2021a. Numerical population estimates update for Southern Right Whales in Brazil. Rep. IWC. SC/68C/CMP.) may cause some bays to reach the carrying capacity, forcing whales to disperse to other bays. This process will possibly result in the gradual recovery of the previous distribution before the whaling impact. In Argentine breeding grounds, mother-calf pairs avoid bays with densities higher than three whales per square kilometre (Sueyro et al. 2018Sueyro N., Crespo E.A., Arias M., Coscarella M.A. 2018. Density-dependent changes in the distribution of Southern Right Whales Eubalaena australis in the breeding ground Peninsula Valdés. PeerJ 6: e5957. https://doi.org/10.7717/peerj.5957 ). Although this pattern has not been investigated in Brazil, new areas of occurrence have been reported in recent years (Renault-Braga et al. 2018Renault-Braga E.P., Groch K.R., Flores P.A.C., et al. 2018. Area usage estimation and spatiotemporal variability in distribution patterns of southern right whales, Eubalaena australis, in southern Brazil. Mar. Ecol. (Berl). 39: e12506. https://doi.org/10.1111/maec.12506 ), suggesting expansion.

Prediction maps showed that hotspots for mother-calf pairs were more coastal than those for unaccompanied adults. The predicted area classified the coastline into two environments: one area formed by several bays; and one with a straight coastline and consequently more exposure to wind and waves (Fig. 7). This pattern of mother-calf pairs being more coastal than unaccompanied adults occurs in both environments (coast with several bays and straight coastline). There are several advantages for mothers to stay near the coast, such as protection of their calves against waves and wind (Best 1990Best P.B. 1990. Trends in the inshore right whale population off South Africa, 1969-1987. Mar. Mamm. Sci. 6: 93-108. https://doi.org/10.1111/j.1748-7692.1990.tb00232.x , Elwen and Best 2004aElwen S.H., Best P.B. 2004a. Environmental factors influencing the distribution of southern right whales on the south coast of South Africa I: broad scale patterns. Mar. Mamm. Sci. 20: 567-582. https://doi.org/10.1111/j.1748-7692.2004.tb01180.x , Rayment et al. 2015Rayment W., Dawson S., Webster T. 2015. Breeding status affects fine-scale habitat selection of the southern right whales on their wintering grounds. J. Biogeogr. 42: 463-474. https://doi.org/10.1111/jbi.12443 ). In breeding areas, right whales have a fasting period. Therefore, they must develop strategies to save energy, mainly for mothers, because nursing calves increase their energy requirements. In addition, mothers must stay longer in breeding areas during calf development than unaccompanied adults (Groch 2005Groch K.R. 2005. Biologia populacional e ecologia comportamental da Baleia Franca Austral, Eubalaena australis Desmoulins, 1822, CETACEA, MYSTICETI, no litoral do Brasil. PhD thesis, Univ. Fed. do Rio Grande do Sul, 169 pp.). Therefore, mothers may select sheltered areas to increase their survival and that of their calves (Elwen and Best 2004aElwen S.H., Best P.B. 2004a. Environmental factors influencing the distribution of southern right whales on the south coast of South Africa I: broad scale patterns. Mar. Mamm. Sci. 20: 567-582. https://doi.org/10.1111/j.1748-7692.2004.tb01180.x , Payne 1986Payne R. 1986. Long-term behavioral studies of the southern right whale Eubalaena australis. Rep. IWC. 10 (Special Issue): 161-168.). Proximity to the coast also reduces predation, as these areas are usually shallow and consequently limit predator attack.

The model indicated a higher contribution of unaccompanied adults at further distances from the coast. However, for mother-calf pairs, the model showed a higher contribution to coastal linearity. Factors that are directly related to coastal characteristics, such as coastal linearity, were more influential in whales that were more coastal, justifying the higher contribution of coastal linearity to the model for the mother-calf pair. Coastal linearity is directly related to the protection of bays against the action of waves and wind, but it has limited influence in areas further away from the coast, where there is little protection. Thus, coastal distance showed more contribution power for models of unaccompanied whales, who possibly frequent areas with little or no protection from the coast.

Staying close to the coast for some species, such as right whales, can create problems if the chosen area is near cities with activities that may impact whales, such as ship collisions (Laist et al. 2001Laist D.W., Knowlton A.L., Mead J.G., Colete A.S., Podesta M. 2001. Collision between ships and whales. Mar. Mamm. Sci. 171: 35-75. https://doi.org/10.1111/j.1748-7692.2001.tb00980.x , Conn and Silber 2013Conn P.B., Silber G.K. 2013. Vessel speed restrictions reduce risk of collision-related mortality for North Atlantic right whales. Ecosphere 44: 1:16. https://doi.org/10.1890/ES13-00004.1 ), underwater noise disturbances (Clark et al. 2009Clark C.W., Ellison W.T., Southall B.L., et al. 2009. Acoustic masking in marine ecosystems: Intuitions, analysis, and implications. Mar. Ecol. Prog. Ser. 395: 201-222. https://doi.org/10.3354/meps08402 , Sousa-Lima and Clark 2008Sousa-Lima, R.S., Clark C.W. 2008. Modeling the effect of boat traffic on the fluctuation of humpback whale singing activity in the Abrolhos National Marine Park, Brazil. Can. Acoust. 36: 174-181., Rolland et al. 2012Rolland R.M., Parks.SE., Hunt K.E., et al. 2012. Evidence that ship noise increases stress in the right whales. Proc. R. Soc. B. 279: 2363-2368. https://doi.org/10.1098/rspb.2011.2429 ) and gillnet fishery interactions (Pontalti and Danielski 2011Pontalti, M. Danielski M. 2011. Right whale, Eubalaena australis Cetacea, Misticeti, entanglement records in the reproductive season of 2010 in Santa Catarina, Brazil. Biotemas 24: 109-112. https://doi.org/10.5007/2175-7925.2011v24n2p109 ). In the predicted hotspots of the study areas, there are five harbours (from north to south: Paranaguá, São Francisco do Sul, Itajaí, Imbituba and Rio Grande), three of which (Paranaguá, Itajhaí and Rio Grande) are commercially active with large ships and maritime traffic. Currently, only the Imbituba harbour has a management plan for the presence of right whales, providing a land-based systematic study throughout its breeding season. Collision can be avoided by reducing vessel speed (Bezamat et al. 2015Bezamat C., Wedekin L.L., Simões-Lopes P.C. 2015. Potential ship strikes and density of humpback whales in the Abrolhos Bank breeding ground, Brazil. Aquat. Conserv. 25: 712-725. https://doi.org/10.1002/aqc.2523 ), and systematic studies can inform vessels of whale presence.

Preference for gently sloping bays is a pattern observed in right whale breeding grounds in South Africa and New Zealand (Elwen and Best 2004aElwen S.H., Best P.B. 2004a. Environmental factors influencing the distribution of southern right whales on the south coast of South Africa I: broad scale patterns. Mar. Mamm. Sci. 20: 567-582. https://doi.org/10.1111/j.1748-7692.2004.tb01180.x , Rayment et al. 2015Rayment W., Dawson S., Webster T. 2015. Breeding status affects fine-scale habitat selection of the southern right whales on their wintering grounds. J. Biogeogr. 42: 463-474. https://doi.org/10.1111/jbi.12443 ). Slope is a factor used to classify bay morphotypes (Pereira et al. 2009Pereira M.D., Schettini C.A.F., Omachi C.Y. 2009. Caracterização de feições oceanográficas na plataforma de Santa Catarina através de imagens orbitais. Rev. Bras. Geof. 271: 81-93. https://doi.org/10.1590/S0102-261X2009000100007 ). Right whales are more frequent in dissipative bays (gentle slopes) that reduce the wave force (Seyboth et al. 2015Seyboth E., Groch K.R., Secchi E.R., Dalla-Rosa L. 2015. Habitat use by southern right whales, Eubalaena australis Desmoulins, 1822, in their main northern calving area in the western South Atlantic. Mar. Mamm. Sci. 314: 1521-1537. https://doi.org/10.1111/mms.12241 ) and consequently save energy for whales.

Substrate type was the variable with the lowest contribution in both models. Despite previous studies indicating that sediment could explain southern right whale distribution (Elwen and Best 2004bElwen S.H., Best P.B. 2004b. Female southern right whale Eubalaena australis: Are there reproductive benefits associated with their coastal distribution off South Africa? Mar. Ecol. Prog. Ser. 269: 289-295. https://doi.org/10.3354/meps269289 ), in Brazilian breeding grounds this variable shows no relationship with whale distribution patterns (Renault-Braga et al. 2021bRenault-Braga E.P., Groch K.R., Simões-Lopes P.C. 2021b Is there spatial segregation between reproductive groups of southern right whales along the coastline of southern Brazil? Mar. Mamm. Sci.: 10.1111/mms.12797. https://doi.org/10.1111/mms.12797 ). In South Africa, right whales prefer areas with sandy substrates and avoid rocky regions (Elwen and Best 2004aElwen S.H., Best P.B. 2004a. Environmental factors influencing the distribution of southern right whales on the south coast of South Africa I: broad scale patterns. Mar. Mamm. Sci. 20: 567-582. https://doi.org/10.1111/j.1748-7692.2004.tb01180.x ). In southern Brazil, there is limited substrate variability, with only sand, silt and clay as soft sediments.

The southern right whale is the only locally endangered whale species that breeds in coastal Brazil (ICMBio 2018ICMBio. 2018. Livro Vermelho da Fauna Brasileira Ameaçada de Extinção volume ii - mamíferos. at https://www.icmbio.gov.br/portal/images/stories/comunicacao/publicacoes/publicacoes-diversas/livro_vermelho_2018_vol2.pdf ). This study provides a foundation for management and development strategies for research and conservation, directing these actions to predicted breeding hotspots.