Dead eels found in stream were rare species
Hundreds of fish found dead in a north Christchurch stream were of a rare species that is declining in number and regarded as being at risk.
About 800 fish and eels were discovered in a four-kilometre section of Kaputone Creek in Belfast on Wednesday.
Environment Canterbury (ECan) investigators are analysing water samples and testing the fish for the cause of the deaths.
They believe the fish were killed by a contaminant, possibly something that entered the stream through the stormwater network or from someone dumping something in the creek.
The Press found dead fish in a section of the stream between Silver Fern Farms’ Belfast plant and where it flows into the Styx River at Marshland Rd.
Eels made up the bulk of the dead animals, some as small as 15 centimetres, others up to a metre in length, often clumped together in groups on the stream bed or washed up at the banks.
Bullies and inanga (whitebait) are also understood to be among the dead fish.
Steve Firth, ECan’s local acting zone manager, said the eels were a mixture of shortfin and longfin species.
Shortfins, found in New Zealand, Australia and on some Pacific Islands, are not threatened.
But the longfin is classified as an ‘‘at risk’’ species, both rare and with declining numbers, according to the Department of Conservation (DOC).
DOC’s website says longfin eels ‘‘are less able to cope with changes to their environment than their shorter-finned relative’’.
‘‘They are heavily affected by human activities, such as pollution, the building of dams, loss of vegetation near their habitat, and overfishing.’’
Inanga are also at risk and in decline.
ECan and the Christchurch City Council removed the dead eels and fish from the creek yesterday.
‘‘We have liaised with local ru¯ nanga about the best next steps, and have agreed on a burial site,’’ Firth said.
‘‘At this stage we are still investigating the source of the contamination so it is too early to confirm anything.
‘‘We have taken water samples over the last two days, which are being analysed to try and determine the type of contaminant. We are still awaiting the results of this.’’
Annabeth Cohen, a freshwater advocate for Forest & Bird, said: ‘‘It is really concerning that our eel – our taonga, our national treasure – are in real trouble and we really can’t afford to lose a huge number like this.
‘‘Water quality is a real issue for our eel and also loss of habitat but we are really concerned when instances like this happen.
‘‘It is definitely shocking to see so many eel die in such a short period of time and I am really concerned about what has gone into the water.’’
Cohen said water quality is an issue across the country, with many rivers and lakes uninhabitable for fish and eels.
‘‘We need to be better about land management so that pollution and contaminants aren’t getting into water in the first place.
‘‘We shouldn’t have to wait for almost 1000 eels to die to get better at our land management.’’