EELS in the fresh waters of the Pevensey Levels have dropped in numbers following a dry spring.
The Environment Agency said low numbers of young eels, known as elvers, have migrated from the sea to fresh water in Pevensey Levels.
European eels spawn off the US coast before returning to mature in European rivers. Numbers have fallen by more than 95 per cent over the last 30 years and the Environment Agency says low rainfall this year could have further disrupted their life cycle.
In a bid to help the eels, the agency has installed man-made channels in the smaller streams in Pevensey to enable the creatures to swim up to the deeper waters where they can grow.
European eels are listed as a critically-endangered species and the dry spring has left some rivers and canals with very low water levels – putting the young eels at greater risk from predators, the agency said.
The elvers are also at risk of dying of exhaustion as they struggle to swim upstream in the low water levels.
However, the Environment Agency said the dry spring was followed by normal levels of rainfall in July.