Population structure and spawning area(s) of tropical eels

Project Details


The search for spawning aggregations of catadromous eels (Genus Anguilla) has a history that began with Aristotle’s hypothesis that eels develop spontaneously from mud and so far culminated with the discoveries of the European (1923) and Japanese eel (1991) spawning areas. Eels live up to several decades in freshwater before they travel across the ocean on a journey that sometimes takes months and ends at their spawning areas. Habitat destruction, overfishing, pollution and introduced parasites have driven several species to near extinction. In eastern Africa and the islands of the southwestern Indian Ocean (SWIO) eels are mythical creatures supporting subsistence fisheries. These countries have recently entered the global trade heedless of the contribution of these migratory fishes to the livelihoods of vulnerable human societies. Worldwide, the eels of the SWIO are the least studied stocks and little is known about the marine phase of their life cycle. We propose to tag the endemic species Anguilla mossambica with satellite transmitters to study their marine migrations from Madagascar and possibly locate their spawning area, which they may share with one or more of the co-occuring species (A. marmorata, A. bicolor bicolor, A. bengalensis labiata). We will explore the oceanographic conditions along the eels’ migration path in order to potentially identify landmarks that the eels could use to find their spawning area. We will use next generation sequencing techniques to reveal population structure and screen for hybrids and backcrosses among all four species of eels throughout their SWIO distribution range. We will connect our research with an ongoing project studying eel recruitment to and escapement from estuaries in South Africa, Mozambique and Kenya granted from the Western Indian Ocean Marine Science Association (2020-2023) to two of the applicants. We have brought together an international team of biologists and oceanographers from Europe, Africa, and Japan. Learning about the locations of the spawning areas of these species and gathering new information about their population structures and potential levels of hybridization will be valuable new information that can help guide future conservation efforts.
Short titleIndian Ocean Eels
Effective start/end date1/06/2130/06/24