Abstract
The presence of populations of the Western Indian Ocean coelacanth (Latimeria chalumnae) in Madagascar is not surprising considering the vast range of habitats which the ancient island offers. The discovery of a substantial population of coelacanths through handline fishing on the steep volcanic slopes of Comoros archipelago initially provided an important source of museum specimens and was the main focus of coelacanth research for almost 40 years. The advent of deep-set gillnets, or jarifa, for catching sharks, driven by the demand for shark fins and oil from China in the mid- to late 1980s, resulted in an explosion of coelacanth captures in Madagascar and other countries in the Western Indian Ocean. We review coelacanth catches in Madagascar and present evidence for the existence of one or more populations of L. chalumnae distributed along about 1000 km of the southern and western coasts of the island. We also hypothesise that coelacanths are likely to occur around the whole continental margin of Madagascar, making it the epicentre of coelacanth distribution in the Western Indian Ocean and the likely progenitor of the younger Comoros coelacanth population. Finally, we discuss the importance and vulnerability of the population of coelacanths inhabiting the submarine slopes of the Onilahy canyon in southwest Madagascar and make recommendations for further research and conservation.Significance:
 
 The paper contributes significantly to knowledge of the distribution and ecology of the Indian Ocean coelacanth, Latimeria chalumnae.
 The paper provides the first comprehensive account of Madagascar coelacanths and demonstrates the existence of a regionally important population and extensive suitable habitat, correcting an earlier hypothesis that coelacanths in southwest Madagascar were strays from the Comoros.
 The results have application in the study of the evolution, biology, ecology and conservation of the species. 
 The significant threat posed by gillnet fishing to coelacanths and other species is highlighted as are the negative effects of the shark-fin trade.
 The paper emphasises the importance of the Onilahy marine canyon in southwest Madagascar as an especially important habitat and provides the basis for the development of a national programme of research and conservation.
Highlights
When a living coelacanth was caught off the coast of South Africa in December 1938 it caused an international sensation
Smith named the new species Latimeria chalumnae[1] and predicted[2] that it was a stray from warmer rocky reefs in the tropical Western Indian Ocean
Over the 14 years, Smith and his wife Margaret scoured the coasts of Mozambique, Tanzania and Kenya looking for coelacanths and collecting other fishes.[2,3]
Summary
When a living coelacanth was caught off the coast of South Africa in December 1938 it caused an international sensation. Madagascar shifted more slowly northwards to its current isolated position in the Western Indian Ocean about 40 million years ago, since when it has experienced relatively stable climatic and oceanographic conditions.[34] This can be compared with the young Comoro islands whose ages range from 15–10 million years (Mayotte) to just 130 000 years (Grande Comore).[35] It is likely that either Madagascar or the African mainland represent the more ancestral habitat of coelacanths before they colonised the Comoros in relatively recent geological time, but this proposal needs to be tested using genetic evidence.
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