A storm water pond near Beaumaris Boulevard in Bethlehem has been polluted following the rainfall on Friday.

Images sent into SunLive from Tauranga resident Marge Heavey show dead eels floating on the surface.

'The eels started dying and floating up to the surface on Friday when the pond was absolutely still, stagnant and looking toxic.

'On Sunday, my husband counted 75 of them dead on the surface. We haven't seen this before in four years, but there has never been such a long dry spell either.

'I don't know how the few ducks at the lake can survive. We also saw one dead Pukeko in the water.”

Tauranga City Council environmental programme leader Radleigh Cairns says both the city and regional councils were assessing the pond on Sunday morning.

'It's pretty difficult, we couldn't find any reasons for the death of the eels.

'They took some samples for pH to check the water and there was no real evidence of what might've killed them.

'The contractors have been back at the site this morning to clean up as many of the eels as they can.”

Radleigh says the rain over the weekend had likely caused contaminants to be washed into the storm water network.

'If the eel's habitat is degrading because of the dry weather and the oxygen is reduced in the pond, they'll just leave and go somewhere else, so for that number of eels to be killed, it's likely that something short and sharp has done it, like pollution in the storm water network.”

There have been no other reported incidents around deaths of eels or large numbers of fish due to the dry weather. Radleigh simply describes it as an ‘eel kill'.

'Unfortunately, because we've had all that dry weather, it is really difficult to pin point when that occurred because it could have been sitting in the line for a number of days, even a couple of weeks without us having any rain, and then washed through.”

Although the council may not be able to identify the source, they plan to send out a mail catchment highlighting the issue.