Anglers are catching a range of fish species rarely seen along the Western Bay coastline, while others are disappearing.
Marine experts said changes in the marine environment had resulted in more hapuku, blue nose, warehou and trumpeter being caught while yellowfin tuna had all but disappeared.
An increase in water temperature and abundance of food were believed to be the main reasons for the arrival of new fish species.
Tauranga fisherman and Top Catch owner Roly Bagshaw said the harbour held "healthy levels of fish".
"Tarakihi has been fishing really well and they've been big, healthy fish. Snapper has been a bit up and down but fishing in the harbour has been excellent," he said.
"Right now the fish are feeding flat-out and there's a lot of tucker available to them - thousands of millions of crabs - that's what's bringing them into the harbour."
Tauranga Sport Fishing Club manager Grant Holley said tarakihi, which were usually found in deeper waters, had moved closer to shore while the yellowfin tuna appeared to have disappeared.
Mr Holley believed this was a result of over-fishing in the Pacific Islands.
Charter fisherman Garth Lelievre said there were more hapuku and blue nose and fewer bottom-feeding fish around. This summer he had caught a trumpeter fish which was rare in the area. He had only caught three trumpeter in 20 years, he said.
- Source: Ministry for Primary Industries