Commercial fishers reported killing or injuring more than 2200 protected species in the past two years, data obtained by Newshub shows.
It includes hundreds of albatross and fur seals. However, given the lack of observer coverage and cameras, the figures are only considered the "tip of the iceberg".
Of the 2248 protected species injured or killed, it included 1039 albatross, 850 petrels, 847 shearwaters and 445 fur seals. A further 5.1 tonnes of protected corals were destroyed.
But Forest and Bird marine consultant Kat Goddard says these figures are just what fishers report they caught.
"There is such a large difference between what commercial fishers are reporting as bycatch and what observers are seeing."
Forest and Bird regional conservation manager Sue Maturin says observers are only on some boats and they don't know what's going on out at sea.
"We don't know who the good fishers are because we can't tell. We don't have cameras on boats and we don't have enough observers on boats. This is just the tip of the iceberg."
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Whitianga commercial fisherman Adam Clow says those only at sea who want to make some fast money without caring for the environment shouldn't be fishing, and there's no room for "cowboy" fishers.
"What I would like to see is the industry being harder on people who have these accidents. Make examples of them."
Clow's been meeting all the new seabird bycatch reduction guidelines for years, such as only fishing at night, and using weighted lines and bird scaring devices.
But he and his crew are also doing more than what's required.
"You have to respect the ocean to be on the ocean. You gotta want to be out there."
He's had cameras for six years and is developing another bit of kit to deter seabirds - a cone-like structure rigged with lights.
"The lights are going to be flashing and we hope to put the seabirds off, send them off to the side and make their vision go blurry for a minute while our bait sinks and goes past them."
There's also a surface longline technology that only releases baited hooks once underwater that's being trialled by Nelson fishing company Altair.
Skadia Technologies founder Kieran Lawton says what they found was by setting hooks by stealth and deep underwater, it meant the birds didn't see the baits and they fly away.
Sealord CEO Doug Paulin says it uses this 'bird-baffler curtain' off the back of its trawlers to fend off birds as the nets are hauled up.
"Then we're looking at potentially batching where you would feed the birds somewhere else and then go and fish in a completely different area."
Paulin says Sealord caught no sea lions in the squid fishery last year. Those boats always have an observer, however, that level of coverage is the exception and not the norm.