Niwa forecaster Nava Fedaeff said New Zealand was surrounded by a marine heatwave, and while it made for more pleasant swimming, it also meant more fish venturing south.
Ms Fedaeff said Auckland’s water temperatures reached 22degC in the middle of December, similar to what was expected in February.
"Sea temperatures have been 4degC above average in some coastal areas and it looks like warm seas are going to be with us throughout the summer season."
Niwa fisheries scientist Darren Parsons said it meant there was likely to be different kinds of fish swimming around our coasts.
"Fish respond over the long term, moving down south to maintain the temperature band that they like to be in.
"The ranges of red snapper and pink maomao are extending further south in response to warming conditions over the last few decades and it will be no different this year."
He said it was not only species common in New Zealand that were on the move.
It was likely there would be more tropical fish too, which would be a delight for game fishers and divers alike.
"We’ll probably be getting some visitors from the tropics.
"Tropical species like warm waters, so they’ll be travelling further south.
"Expect more species such as marlin, mahi-mahi and little tropical vagrant species to turn up in Poor Knights Islands."
"This means they need to eat more.
"This is great news for fishers — getting a good catch might be a lot easier this year.
"If the fish are hungry, they’re more likely to eat your bait."
Dr Parsons said it was not only this year that people might be in for a good haul.
"Snapper, for example, do their spawning migrations in spring when the water reaches about 16degC, and in the past, warmer years have led to more successful spawning.
In around five years any fertilised eggs would have grown into fish big enough to catch.
He suggested 2026 could be a bumper year — "mark it in your calendars".
