With the Lake open since mid December (it closed on February 21st), and the very warm weather, the water of the lake is shallower, warmer and saltier than usual. TV3 News reported on 1000s of goldfish seeking refuge in the Selwyn River and other tributaries – the link to view the clip is here.
The goldfish, which are an introduced species, have probably been in the lake for a number of years and are likely to be the result of someone emptying their aquarium or goldfish pond. Feral goldfish lack the bright colours and feathery fins of their domestic relatives, but are the same species
DOC have commented that, although not officially a pest species, they do have a detrimental impact on the environment by eating vegetation, undercutting banks, and stirring up sediment. A huge effort would be needed to control the goldfish as there are likely to be large numbers present.
The key message is don’t release non native species into the NZ environment – this could be the result!