IUCN – SSC Cetacean Specialist Group

Atlantic humpback dolphins

IUCN – SSC Cetacean Specialist Group / Atlantic humpback dolphins

Updated November 2023

Background, threats and conservation status

Endemic to Central and West Africa, the Atlantic humpback dolphin (Sousa teuszii, from here on referred to as AHD) is one of the least understood of the dolphin species. Despite the dependence of AHD on nearshore habitats that bring them into close contact with human activities throughout the range, a lack of targeted field research has hampered the collection of information on all aspects of the species ecology, including a lack of data on their distribution, population size, ecology, behaviour, life history, threats and mortality.

Atlantic humpback dolphins (Sousa teuszii) in the Saloum Delta, Senegal. Photographed during a March 2022 survey conducted by the African Aquatic Wildlife Foundation (AACF) and the Consortium for the Conservation of the Atlantic Humpback Dolphin (CCAHD).

The species’ range extends from Western Sahara in the north to Angola in the South, with presence confirmed in 13 of the 19 countries within that range (Weir and Collins, 2015; Collins et al., 2017). In many of these countries evidence is limited to a handful of historical, anecdotal, stranding or bycatch records, and where no records exist, it is unknown whether this reflects a true gap in distribution, or a lack of survey effort. Systematic surveys for AHD have been limited to Angola (Weir, 2009), Congo (Collins et al., 2014), Gabon (Collins et al., 2014; Minton et al., 2017), Cameroon (Ayissi et al., 2014), Senegal (Van Waerebeek et al., 2003; Weir, 2016; Minton et al. 2022), and Guinea (Weir, 2015; Bamy et al., 2021). Most of these studies have been limited in time and scope, ranging from a few days to a few weeks. Based on this scant evidence, as well as a review of published estimates of abundance in each state, it has been estimated that fewer than 3,000 individuals remain throughout the species’ entire range of which half are likely to be breeding adults (Collins, 2015; Collins et al., 2017).

As with other coastal small cetaceans, bycatch in artisanal gillnets is thought to pose the most significant threat to AHD (Collins, 2015; Brownell et al., 2019), while coastal development, habitat degradation, and directed hunts/aquatic bushmeat are also likely to play roles in population declines (Weir et al., 2021; Ingram et al., 2022). These documented threats, low abundance, and likely declines led to an uplisting of the species from Vulnerable in 2012 (Reeves et al., 2012) to Critically Endangered in 2017 (Collins et al., 2017).

 

Conservation Efforts

Dedicated conservation efforts for this species started in the late 1990s when the Convention on the Conservation of Migratory Species (CMS) supported the West African Cetacean (WAFCET) project (Van Waerebeek et al., 2000, 2003). Under this initiative, a number of range country scientists collaborated with international researchers to conduct beach, boat and interview surveys to establish a baseline of data on cetacean distribution and conservation status in the West Africa region, with collaborations continuing to the present day (e.g., Van Waerebeek et al., 2004; Segniagbeto et al., 2014; Van Waerebeek et al., 2017; Bamy et al., 2021). A CMS Concerted Action for the species was approved by the Conference of Parties in 2017, and the CMS has commissioned a Single Species Action Plan, a draft of which has undergone multiple rounds of consultations with experts and range country representatives, and will be presented for endorsement at the next CMS Conference of Parties in February 2024.

Reports to the Scientific Committee of the International Whaling Commission have highlighted the conservation status of AHD from 2002 onward with increasingly urgent recommendations for research and threat mitigation (e.g., IWC, 2003, 2011, 2020; Collins et al., 2004; Van Waerebeek and Perrin, 2007; Weir et al., 2020).

The IUCN has also recognised AHD as one of the seven cetacean species most likely to follow the path of the Yangtze River dolphin (Turvey et al., 2007) and vaquita (Jaramillo-Legorreta et al., 2019) towards extinction unless urgent conservation action is taken (Taylor et al., 2020). As such, the AHD is one of the species of concern for the IUCN’s Integrated Conservation Planning for Cetaceans (ICPC) Initiative.

CSG members have collaborated with international and range country scientists and conservation organisations to form the Consortium for the Conservation of the Atlantic Humpback Dolphin (CCAHD). The CCAHD’s aim is to provide robust conservation advice on the AHD. The Consortium has formal legal status as a Foundation in the Netherlands, governed by a Management and Supervisory Board that includes international and range country scientists and managers.

In 2020, 11 working groups undertook an exercise to systematically prioritise conservation actions which are summarised in this report and the CCAHD 5-year strategic plan.

A range of resources for the general public, managers, and researchers are available on the CCAHD’s trilingual website and are intended to support better understanding of the species and its conservation needs at all levels. Projects currently underway through collaboration between the CCAHD  and range country partners include an IUCN SSC EDGE-supported series of government stakeholder engagement meetings, AHD surveys in the Saloum Delta in Senegal, a multi-country fisheries interview project, and a three-year multifaceted research and conservation project in Guinea. Collaboration and support through the CCAHD has already yielded increased reporting and documentation of AHD in Congo, Cameroon and Nigeria, and it is hoped that continued collaboration will facilitate more systematic reporting and surveys throughout the species’ range.

 

Infographic produced by The Consortium for the Conservation of Atlantic Humpback Dolphins (CCAHD). A trilingual website also provides information about the species throughout its range, and resources ranging from searchable literature lists to outreach and education materials that can downloaded. https://www.sousateuszii.org/

 

Urgent Funding Needs

Further to these projects, the following priority actions have been identified, for which funding is urgently needed:

Research team searching for Atlantic humpback dolphins in the Saloum Delta, Senegal. The CCAHD engages in local capacity building as well as research and awareness raising.

  • Field surveys, initially focusing on the Senegal-Gambia region, but extending into other range states as soon as resources and capacity allow. These will include multiple methods including photo-identification, water parameter sampling, eDNA and acoustics, to better understand distribution, abundance, habitat use and some aspects of the species’ behaviour and biology. In addition to addressing knowledge gaps, these surveys will build capacity through the involvement of local scientists and conservation organisations.
  • Design and implementation of local ecological knowledge (LEK) interview surveys to better understand distribution and threats to AHD. These will target fishers and coastal community members to harness local knowledge and understanding of the dolphins’ distribution and habitat use as well as the threats they face from bycatch or other coastal activities.
  • In-depth assessments of the risks posed to AHD by small-scale coastal fisheries as well as coastal development projects throughout the species range. These can build on the LEK interview surveys and incorporate habitat modelling and inventories of planned coastal construction or other industrial activities that may impact AHD habitat.
  • Formation of local or national reporting and/or stranding networks, and provision of support for individuals or organisations willing to act as data collectors for these networks. This will improve knowledge of the species’ distribution, as well as provide evidence for causes of mortality, threats, health and life history parameters.
  • Development of materials (in appropriate target languages) to support outreach and awareness raising for different stakeholder groups ranging from schools and coastal (fishing) communities to park rangers, government managers or industry stakeholders. These can be made available through the trilingual CCAHD website as well as workshops, or face-to face meetings.
  • Organisation of workshops and educational outreach events in coastal communities bordering AHD habitat, to disseminate educational materials and engage communities in grassroots conservation efforts, beginning with awareness and reporting networks, and working toward a longer-term goal of community-based sustainable conservation strategies.
  • Targeted outreach to government and industry stakeholders to raise awareness of AHD and the threats they face, in order to promote and offer support for conservation planning and mitigation of bycatch and other threats.
  • Increased support for cetacean scientists and conservation organisations in AHD range states, through provision of hands-on training, remote or in-person lectures, data collection protocols and guides.

 

In June 2021, with support from an IUCN-SSC EDGE grant, government stakeholder engagement meetings were held in Gabon, Cameroon and Senegal to raise awareness of Sousa teuszii conservation needs and encourage adequate conservation planning for the species.

 

References

Ayissi, I., Segniagbeto, G.H. and Van Waerebeek, K., 2014. Rediscovery of Cameroon dolphin, the Gulf of Guinea population of Sousa teuszii (Kükenthal, 1892). International Scholarly Research Notices, 2014.

Bamy, I. L., A. Djiba, and K. Van Waerebeek. 2021. Recent survey for delphinids at Tristao Islands, Guinea, reinforces concern for bycatches and marine bushmeat use. Preprints (Posted 5 April 2021):16. doi: doi:10.20944/preprints202104.0094.v1

Brownell Jr, R. L., R. R. Reeves, A. J. Read, B. D. Smith, P. O. Thomas, K. Ralls, M. Amano, P. Berggren, A. M. Chit, T. Collins, R. Currey, M. L. L. Dolar, T. Genov, R. C. Hobbs, D. Kreb, H. Marsh, M. Zhigang, W. F. Perrin, S. Phay, L. Rojas-Bracho, G. E. Ryan, K. E. W. Shelden, E. Slooten, B. L. Taylor, O. Vidal, W. Ding, T. S. Whitty, and J. Y. Wang. 2019. Bycatch in gillnet fisheries threatens Critically Endangered small cetaceans and other aquatic megafauna. Endangered Species Research 40:285-296.

Collins, T. 2015. Re-assessment of the Conservation Status of the Atlantic Humpback Dolphin, Sousa teuszii (Kükenthal, 1892), Using the IUCN Red List Criteria. In: A. J. Thomas and E. C. Barbara, editors, Advances in Marine Biology Volume 72: Humpback dolphins (Sousa spp.) current status and conservation: Part I No. Volume 72. Academic Press. p. 47-77.

Collins, T., G. T. Braulik, and W. Perrin. 2017. Sousa teuszii, The IUCN Red List of Threatened Species. e.T20425A50372734. Downloaded on 10 December 2017., http://www.iucnredlist.org/details/20425/0.

Collins, T., S. Ngouessono, and H. C. Rosenbaum. 2004. A note on recent surveys for Atlantic humpback dolphins, Sousa teuszii (Kukenthal, 1892) in the coastal waters of Gabon. SC/56/SM23, International Whaling Commission.

Collins, T., S. Strindberg, R. Mboumba, E. Dilambaka, J. Thonio, C. Mouissou, R. Boukaka, G. K. Saffou, L. Buckland, R. H. Leeney, R. Antunes, and H. Rosenbaum. 2014. Progress on Atlantic humpback dolphin conservation and research efforts in Congo and Gabon. Document presented to the Scientific Committee of the International Whaling Commission SC/65a/SM16 Rev:24.

Ingram, D.J., Prideaux, M., Hodgins, N., Frisch-Nwakanma, H., Avila, I.C., Collins, T., Cosentino, M., Keith-Diagne, L., Marsh, H., Shirley, M.H., Van Waerebeek, K., Djondo, M.K., Fukuda, Y., Glaus, K.B.J., Jabado, R.W., Lang, J.W., Limpus, C.J., Luber, S., Manolis, C., Webb, G.J.W., Porter, L., 2022. Widespread use of migratory megafauna for aquatic wild meat in the tropics. Frontiers in Marine Science 9.

IWC. 2003. Report of the 54th meeting of the Scientific Committee of the International Whaling Commission – Annex K Small Cetacean Subcommittee. Journal of Cetacean Research and Management

IWC. 2011. Report of the 62nd meeting of the Scientific Committee of the International Whaling Commission – Annex L Small Cetacean Subcommittee. Journal of Cetacean Research and Management

IWC. 2020. Report of the Scientific Committee of the International Whaling Commission: SC/68B, International Whaling Commission, Cambridge, United Kingdom.

Minton, G., J. R. Kema Kema, A. Todd, L. Korte, P. B. Maganga, J. R. Migoungui Mouelet, A. M. Nguema, E. Moussavou, and G. K. Nguélé. 2017. Multi-stakeholder collaboration yields valuable data for cetacean conservation in Gamba, Gabon. African Journal of Marine Science 39(4):423-433. doi: 10.2989/1814232X.2017.1398106

Minton, A.G., Keith-Diagne, L., Seck, D., Cerchio, S., Tregenza, N., Takoukam Kamla, A., Eniang, E., Senhoury, C., Sallah-Muhammed, Y., Lene, A., Cristiano, N., 2022. Preliminary results of 2021 and 2022 Sousa teuszii surveys in the Saloum Delta, Senegal. Document presented to the Scientific Committee of the International Whaling Commission SC/68D/SM/12.

Reeves, R. R., T. Collins, T. Jefferson, L. Karkzmarski, K. Laidre, G. O’corry-Crowe, L. Rojas-Bracho, E. Secchi, E. Slooten, B. D. Smith, J. Y. Wang, and K. Zhou. 2012. Sousa teuszii. In: IUCN (ed.) IUCN Red List of Threatened Species No. Version 2012.2.

Segniagbeto, G. H., K. Van Waerebeek, J. E. Bowessidjaou, K. Ketoh, T. K. Kpatcha, K. Okoumassou, and K. Ahoedo. 2014. Annotated checklist and fisheries interactions of cetaceans in Togo, with evidence of Antarctic minke whale in the Gulf of Guinea. Integrative Zoology 9(1):1-13. doi: 10.1111/1749-4877.12011

Taylor, B. L., G. Abel, P. Miller, F. Gomez, L. von Fersen, D. P. DeMaster, R. R. Reeves, L. Rojas-Bracho, D. Wang, and F. Cipriano. 2020. Ex situ options for cetacean conservation: December 2018 workshop, Nuremberg, Germany, IUCN, Gland, Switzerland.

Turvey, S. T., R. L. Pitman, B. L. Taylor, J. Barlow, T. Akamatsu, L. A. Barrett, X. Zhao, R. R. Reeves, B. S. Stewart, K. Wang, Z. Wei, X. S. Zhang, L. T. Pusser, M. Richlen, J. R. Brandon, and D. Wang. 2007. First human-caused extinction of a cetacean species? Biology Letters 3:537-540.

Van Waerebeek, K., Ndiaye, E., Djiba, A. and Diallo, M., 2000. A survey of the conservation status of cetaceans in Senegal, the Gambia and Guinea-Bissau WAFCET-I Report. Convention on the Conservation of Migratory Species (CMS); UNEP.

Van Waerebeek, K., L. Barnett, A. Camara, A. Cham, M. Diallo, A. Djiba, A. Jallow, E. Ndiave, A. O. Ould-Bilal, and I. L. Bamy. 2003. Conservation of cetaceans in the Gambia and Senegal, 1999-2001, and status of the Atlantic humpback dolphin, UNEP/CMS. Bonn, Germany.

Van Waerebeek, K., L. Barnett, A. Camara, A. Cham, M. Diallo, A. Djiba, A. Jallow, E. Ndiaye, A. Samba Ould Bilal, and I. Bamy. 2004. Distribution, status, and biology of the Atlantic humpback dolphin, Sousa teuszii (Kükenthal, 1892). Aquatic Mammals 30(1):56-83.

Van Waerebeek, K., and W. F. Perrin. 2007. Conservation status of the Atlantic humpback dolphin, a compromised future? CMS/ScC14/Doc.6, 14th Meeting of the CMS Scientific Council, Bonn, Germany.

Van Waerebeek, K., M. Uwagbae, G. H. Segniagbeto, I. L. Bamy, and I. Ayissi. 2017. New records of Atlantic humpback dolphin in Guinea, Nigeria, Cameroon and Togo underscore fisheries pressure and generalised marine bushmeat demand. Revue d’Ecologie (Terre et Vie) 72:192-205.

Weir, C., R. H. Leeney, and T. Collins. 2020. Reinvigorating conservation efforts for the Atlantic humpback dolphin (Sousa teuszii): A brief progress report. Document presented to the Scientific Committee of the International Whaling Commission SC/68B/SM/07:1-20.

Weir, C. R. 2009. Distribution, behaviour and photo-identification of Atlantic humpback dolphins Sousa teuszii off Flamingos, Angola. African Journal of Marine Science 31(3):319-331.

Weir, C. R. 2015. Photo-identification and habitat use of Atlantic humpback dolphins Sousa teuszii around the Río Nuñez Estuary in Guinea, West Africa. African Journal of Marine Science 37:325-334. doi: https://doi.org/10.2989/1814232X.2015.1069757

Weir, C. R. 2016. Atlantic humpback dolphins Sousa teuszii in the Saloum Delta (Senegal): distribution, relative abundance and photo-identification. African Journal of Marine Science 38(3):385-394. doi: 10.2989/1814232X.2016.1216893

Weir, C. R., and T. Collins. 2015. A Review of the Geographical Distribution and Habitat of the Atlantic Humpback Dolphin (Sousa teuszii). In: T. A. Jefferson and B. C. Curry, editors, Advances in Marine Biology Volume 72: Humpback dolphins (Sousa spp.) current status and conservation: Part I. Advances in Marine Biology No. Volume 72. Academic Press. p. 79-117.

Weir, C. R., G. Minton, and T. J. Q. Collins. 2021. Conservation of Africa’s Most Imperiled Cetacean, the Atlantic Humpback Dolphin (Sousa teuszii), The Encyclopedia of Conservation: Reference Module in Earth Systems and Environmental Sciences. Elsevier. p. 1-12.