Pollutant likely killed healthy brown trout in Arrowtown creek

Wednesday, 7 June 2017

A pollutant likely caused the death of 16 brown trout in a spawning stream for Lake Hayes - the Queenstown Lake District's 'most polluted lake'.

Fish and Game officer Paul van Klink said the dead trout were found in Mill Creek, downstream of Speargrass Flat Road bridge, by a resident last week.

'The brown trout were all adults, of mixed sex and have moved up into Mill Creek within the last month to spawn. The fish appear to have died over a period of a week of more. Several are pre-spawning fish which are in great condition and full of eggs while others have spawned. Each year during the spawning season we get a few natural fish deaths but this situation is not the norm.'

There were 'plenty' of live brown trout spawning upstream of where the dead fish were found, he said.

'It is highly likely that a contaminant has entered the waterway and killed the fish… Something is going on. They were in good condition…it's definitely something in that water that has caused them to die.'

Water quality and quantity was a 'big' issue in Otago, and he supported community calls for more monitoring in Lake Hayes, particularly with intensive development polluting the lake.

'In terms of the Queenstown Lakes District it's the most polluted water we have got without a doubt…In my view Lake Hayes is more important to have monitoring done than any of the big lakes.

'The bigger picture is we have contaminants entering Lake Hayes through development…Lake Hayes was a perfectly healthy ecosystem but we are having an impact on it. If there is no balance we are causing the degradation of the water ways and Lake Hayes is clearly suffering. It is a lake that is not healthy. It's not completely dead either. It can be turned around and it's going to take the community to turn it around. '

Spawning sports fish were protected and people harming spawning areas or disturbing fish could face prosecution, he said.

Fish and Game had contacted the Otago Regional Council about the deaths, he said.

Friends of Lake Hayes Society chairman Kerry Dunlop said he was not aware of the dead fish but it highlighted the group's plea for long-term monitoring buoys for the lake and various tributaries.

'It's a real concern. Not only have the number of fishing days reduced dramatically in the last five to six years, there is an issue of fish health we need to better understand. '

The group made a plea for the third time for increased monitoring at the regional council's recent annual plan submissions hearing in Queenstown, he said.

 'I was appalled. They flouted our offer of goodwill….The chairman refuted the need for more scientific study and supporting the purchase of monitoring buoys.'

The council had also 'poured cold water' over the offer of help from 'citizen scientists', he said.

'I thought it was a disgrace…We suggested the best four (restoration) options but the first thing is to get an effective monitoring system.'

At the hearing, ORC chairman Stephen Woodhead told Dunlop that Lake Hayes had been investigated over 'decades' and council had suggested to put aside $60,000 in the annual plan for 'scoping work' to be carried out on the lake.

'The team is reviewing the monitoring programme, primarily around the lakes. Whether it means we will get buoys or not, we will have to wait and see…Council is essentially saying, 'enough monitoring'. Monitoring will be ongoing but let's see if there is actually an option that is feasible and fundable.'

• Fish and Game staff are urging residents or contractors to make contact if they have additional information that can help with their inquiry.