Unsettled weather and sea conditions have taken a toll on some Auckland-based snorkellers this summer.
At Cape Rodney-Okakari Pt Marine Reserve unusual ocean currents have kept water temperatures round a chilly 20C and visibility was diminished following last year's storms and the recent king tide.
Kwinten De Vos, the manager at Seafriends - which equips groups of snorkellers visiting the popular Goat Island reserve - hopes more settled weather will bring improved conditions over the next few weeks.
"We have certainly had some good days but we have also had some school groups cancel out completely, for example following the king tide at the weekend," he says.
More than 200,000 visitors a year are drawn to the reserve by the abundance of fish, which have flourished during 35 years of protection from fishing.
However, De Vos recommends coming equipped with a wetsuit, or to be prepared to hire one: "It's been slightly colder, so people without wetsuits don't stay in the water as long.
"Generally you need to be able to remain still if you want to observe fish. And of course people without wetsuits get out sooner, having used up more energy swimming around."
The reserve has an abundance of Australasian snapper, some of which come in close to divers, perhaps remembering an era about 10 years ago when visitors were encouraged to feed fish. The Department of Conservation no longer allows this.
After the road to Goat Island was re-shaped in 1998, mud run-off caused crayfish numbers to fall by 85 per cent, said former Seafriends owner Floor Anthoni.
Seafriends last year hosted several school groups which made torch-lit night dives in the marine reserve.
Snorkellers intending to swim out to rocky Goat Island should carry footwear (jandals or sandals), to protect their feet.