Four large eels have been found dead in the Kākāriki Stream, under Waikanae's David St bridge, in mysterious circumstances.
Kāpiti Mana Forest & Bird chairman Russell Bell was saddened by the deaths.
"They hung out under the bridge in the shade during the day and I used to see them hunt up and down the stream during my evening walks.
"Eels can spend 20 to 60 years and longer in New Zealand rivers, lakes and wetlands depending on species.
"They eat insect larvae, worms and water snails, then as they get bigger, fish and fresh-water crayfish.