Conger Eel (Rhynchoconger flavus) leptocephalus. Many eels pass through a larval stage known as a leptocephalus larvae (plural = leptocephali). The stage can last from months to years depending on the species and prevailing environmental conditions. The Sargasso Sea and the Gulf of Mexico are key reproductive and larval stage areas for several species of eel, including a number of freshwater species that return to the sea to breed. This is a larval individual of the Yellow Conger Eel (Rhynchoconger flavus) and was captured in a trawl between 1,000 and 600 meters depth in the Gulf of Mexico, 2016. Image courtesy of the DEEPEND project.