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Sea cows in the Sahel : research and conservation on the African Manatee in the Senegal and Niger River Basins

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Presented during the 17h Annual Sahelo-Saharan Interest Group Meeting organized by the NGO Sahara Conservation Fund in Senegal, from 4 to 6 May 2017. The Sahara Conservation Fund (SCF) gathers every year about a hundred people who are interested in the field of Sahelo-Saharan species conservation.

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Sea cows in the Sahel : research and conservation on the African Manatee in the Senegal and Niger River Basins

  1. 1. 17th Annual Sahelo-Saharan Interest Group Meeting 2 days of talks on biodiversity conservation in the Sahara and in the Sahel Research on Conservation of Sea Cows in the Sahel Lucy KEITH-DIAGNE, Executive Director - African Aquatic Conservation Fund May 4– 6, 2017
  2. 2. Sea Cows in the Sahel: Research and Conservation on the African Manatee (Trichechus senegalensis) in the Senegal and Niger River Basins Lucy Keith-Diagne, PhD Photo courtesy of SAED, Senegal
  3. 3. African Manatee General Facts § First specimen for science collected by Michel Adanson in the Senegal River, 1752. Described by Link, 1795. § Average length is 249 cm, estimated weight 440 – 880 lbs. (200 - 400 kg). § Life span is at least 39 years § Most closely related to W. Indian manatees but smaller § Most life history parameters are unknown (age of maturity, calving interval, home range size, etc.)
  4. 4. African Manatee Species Overview § Hunting and fisheries bycatch are the biggest threats, followed by dams, human development, and habitat destruction § Protected by national laws in all range countries § IUCN Red List classification: Vulnerable § Appendix I species under CITES and CMS § Live in a wide range of different ecosystems across their 21 country range
  5. 5. ` Map courtesy of Ellen McIlhinny and Ellen HinesBase map courtesy of Ellen McIllhinney Existing major dams Major dams under construction
  6. 6. § Began in Gabon in 2006 § Country-wide distribution surveys and threat assessments § Genetics: population level analysis § Feeding Ecology: analysis of manatee food sources and habitat use § Age determination study § Manatee rescues (orphans, injured) § Training programs § Educational outreach § Alternative livelihood programs § Lead network with collaborators in 19 countries African Manatee Project Overview
  7. 7. Genetics Research Questions § How many different distinct populations are there across the species range? § What is the genetic diversity of the species across its range? § Are populations isolated by dams in trouble? § What impact is hunting having on populations? § Evolution in relation to other manatee species Results will be used for conservation actions- working to save the most endangered populations
  8. 8. Southern regional clade Niger River Northern regional clade Mitochondrial DNA Control Region West Indian manatee
  9. 9. Base map courtesy of Ellen McIlhinny n=20 n=18 n=2 n=1 n=1 n=1 n=10n=2 n=2 n=2 Current North-South population boundary Haplotype Number of Seqs Color TS-CR01 12 TS-CR02 2 TS-CR03 2 TS-CR04 2 TS-CR05 1 TS-CR06 1 TS-CR07 8 TS-CR08 3 TS-CR09 1 TS-CR10 2 TS-CR11 1 TS-CR12 2 TS-CR13 2 TS-CR14 2 TS-CR15 1 TS-CR16 3 Y01 Guinea-Bissau 1 Y02 Guinea Bissau 1 Y02 Senegal coast* 2 Y03 Ghana 1 Y03 Cote D'Ivoire* 1 Y03 Gabon* 8 Y04 Chad 1 Y04 Niger* 1 Y05 Niger 1 n=4 Control Region Haplotypes
  10. 10. Control Region Haplotypes
  11. 11. Control Region Haplotypes- Niger River
  12. 12. Results: Control Region Divergence Dating Tree created by S. Chen and R. Hodel
  13. 13. § First satellite tracking study of the African manatee § 5 manatees rescued Jan. 14-15, 2009 (3 males, 2 females) § Morphometrics, genetics samples, and ID photos collected § 3 manatees satellite tagged (2 males, 1 female) § Transported 6.4 km to the release site by tractor with trailer Senegal River Tracking study Navel Dam
  14. 14. § Tracking periods lasted between 86-325 days. § Tagged manatees used over 308 km of the Senegal River, north and the south of the release location. § Each manatee had very different movement patterns, but all three made directed trips to specific locations. § The female was confirmed returning to a flooded area at Kanel at the end of the dry season. § The Navel dam grates were removed, and no manatees were subsequently trapped Results Mboumba Bababé Kaédi Matam Kanel Bakel Bokiladji
  15. 15. Feeding Ecology § African manatees live in a wide range of habitats from Sahel to rainforest, so their diet is expected to vary between ecosystems § African manatees are difficult to study in the wild § Local people report that African manatees eat mollusks and fish throughout their range § When we understand what food resources manatees need, we will know which habitats to protect © Tomas Diagne 3 manatee noses, Navel, Senegal Catfish eaten by manatees, Patouwel, Senegal
  16. 16. Stable Isotope Results- Senegal River Food species GLG, Recent GLG, Historic Internal, Recent Internal, Historic A. dahomeyensis (mussel) 0.06 0.09 0.08 0.09 C. aegyptiaca (mussel) 0.06 0.09 0.09 0.09 M. rostrata (mussel) 0.06 0.09 0.09 0.09 Mollusk total proportion 0.19 0.26 0.25 0.27 A. macrolepidotus (silverfish) 0.08 0.09 0.10 0.09 C. anguillaris (catfish) 0.07 0.08 0.09 0.09 Synodontis sp. (catfish) 0.09 0.09 0.10 0.09 Fish total proportion 0.24 0.26 0.29 0.27 C. natans 0.14 0.12 0.11 0.11 Echinochloa sp. 3 0.15 0.12 0.12 0.12 Echinochloa sp. 4 0.16 0.12 0.12 0.12 Najas sp. 0.12 0.12 0.11 0.11 Plant total proportion 0.57 0.48 0.46 0.46 Manatees n = 7 Recent, n = 5 Historic, n = 2
  17. 17. Educational Outreach § Over 50 programs conducted last year in Senegal, Gabon, Mali, Nigeria, and Cameroon § 5000 people reached annually § Materials developed for use in multiple countries §Art contests §Gabon: murals, effectiveness study
  18. 18. African Manatee Regional Network § Over 90 African biologists from 19 countries trained since 2008 § Basic field equipment provided to researchers in 11 countries § Manatee fieldwork has increased in at least 10 countries § Increased knowledge about the species now directs conservation actions Nigeria Cameroon 2014 Benin © Tomas Diagne © Aristide Kamla© Edem Eniang
  19. 19. Thanks to MANY African colleagues
  20. 20. Acknowledgements:
  21. 21. Thank You!! africanaquaticconservation.org

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