Queentown’s idyllic summer may be to blame for fish deaths in Lake Hayes.
Otago Regional Council’s (ORC) taken water samples from the lake after several dead fish washed up on the shore over the past week.
Arrowtown resident Noel Flahive noted six or seven dead fish, believed to be perch and brown trout, near the shoreline at the northern end of the lake while walking there on Sunday.
‘‘I thought it had been fishermen who had caught them and just flicked them aside.
‘‘I went back later and there was an ORC fellow there and he said it had been a problem just … in the last few days — all these fish were coming out of the lake and dying on the fringe.’’
Flahive says he got a ‘‘hell of a shock’’ seeing the dead fish.
ORC compliance manager Tami Sargeant says the regional council’s pollution hotline received two complaints relating to the dead fish last week.
Both times, ORC compliance staff visited the lake and while they haven’t identified a pollution source, they did find some dead fish.
‘‘Water samples were taken for testing and we’re currently waiting the results of those,’’ Sargeant says.
‘‘We also notified Fish & Game.’’
Fish & Game officers also visited the lake on Tuesday after noon and discovered two ‘‘relatively fresh’’ dead brown trout on the shore.
They subsequently notified ORC.
Sargeant says data from a monitoring buoy in the lake shows the temperature of its upper level’s hovering around 22degC.
That exceeds the ‘‘chronic temperature threshold’’ for brown trout, which is seven days of continuous temperatures above 19.8degC.
While there are cooler, ‘‘refuge areas’’ in parts of the lake for fish during warm spells, if fish aren’t in those areas, and exposed to prolonged periods of stress, that can result in mortalities, she says.
