it is these adults that start their migration back to the ocean to reproduce. as for the lifespan of these animals, observations confirmthat the european eel can live from 3 to 18 years in a river, return journeys for spawning can take about 1 year. in new zealand, researchers have found an eel that is over 100 years old. in the case of the polynesian eel, we do not have suffcient information or years of observations. Puhi, the Polynesian eel Three of the nineteen known species of freshwater eel occur in French polynesia  : two are long-finned, one short-finned. The first is the giant mottled eel – Anguilla marmorata or puhi pa’a in Tahitian – it is distinctive because of the dark marbling on its body. An adult can attain remarkable sizes and weights, for example 2 meters in length and 20kg weight, and they can adapt to all types of river. the second species, the polynesian long-finned eel or mountain eel – Anguilla megastoma or puhi mau’a –, that is identified by its light brown color and the protrusion on its head, it prefers to live at the heads of steep valleys in mountain rivers, (at more than 800m altitude). The last, the pacific short-finned eel or mud eel – Anguilla obscura ou puhi vari –, is black in color, smaller in size than both the other species and prefers stagnant water. The first is found across the indo-pacifique the last two occur in the pacific. herehia helMe, Docteur en enVironneMent, à l’oriGine Des recherches sur les anGuilles De tahiti/herehiA helMe, ph.d. iN eNviroNMeNTAl sCieNCe is AT The origiN oF The TAhiTi eels reseArChes. nature « A river is healthy if there are eels » The eel is an ecological indicator, as the fish is the largest predator found in polynesian rivers, it maintains the balance in the freshwater food-chain. « A river is healthy if there are eels » is a polynesian saying ; which doesn’t mean that eels clean the water of pollutants, but rather that if the eels are healthy, then the rest of the food-chain is healthy too. several factors could threaten the animal’s survival  : loss of habitat (dredging and diverting rivers for industrial or agricultural purposes) ; water pollution, to which eels are very sensitive ; climate change that alters the direction of ocean currents ; illnesses, the most well-known being the nematode parasite Anguillicola crasus that affects the eel’s ability to swim ; habitat fragmentation, and the presence of barriers, both natural (waterfalls) and anthropogenic (barrages, catchments), and, of course, overfishing. eels are an integral part of polynesian culture. they are considered to be sacred, and are the subject of legends, often being mentioned during cultural events. The best known of the legends is that of « hina » or « the coconut-palm » which tells how the first coconut came into existence, sprouting from an eel’s head, that had been buried in the earth. The coconut palm’s fruits, the coconut, once husked, has three marks on it that are said to represent the animal’s eyes and mouth. For this reason, eels are worshiped as sacred the guardians of the « fenua » (« land » in the polynesian language). p.Bacchet le lac Vaihiria, au centre De l’île De tahiti/The vAihiriA lAke, iN The CeNTer oF The islANd oF TAhiTi. 93 p.Bacchet