Environmental officer Nathan Manning uses a hydro-lab to measure the pH and oxygen levels of the lake. PHOTO: MARK PRICE : Getting to grips with slippery issue

Some anglers say lake snow is clogging their gear and stopping them from fishing certain parts of the lake. PHOTOS: SUPPLIED & MARGOT TAYLOR : Getting to grips with slippery issue

The inlet filter of a boat after two days of cruising Lake Wanaka in February. The owner said the filter was cleaned two days before entering the lake. : Getting to grips with slippery issue