The Tauranga City Council has issued a warning to residents following the death of about 25 eels in a stormwater drain after what looks like chemical burns.
Staff from both the Tauranga Council and the Bay of Plenty Regional Council found between 40 and 50 short-finned eels either dead or in distress yesterday at an outlet at the end of Grace Road near Tauranga's Memorial Park.
They did not detect household chemicals in the water but said it was likely whatever chemically burnt the animals had flushed through before staff arrived.
Tauranga Council consents officer Toby Barach said nearly half of the eels had died.
He said drains around the outside of houses and on the street were for rainwater and urged people to be careful what they let go down them, as they were likely to drain straight into the harbour with no stormwater treatment.
He said whatever went into drains could have a major impact on the environment.
Mr Barach said it was the third time in seven years he had seen dead or dying eels in the city.
He said it was likely that most of the eels found distressed yesterday would have since also died, although some could have survived.