"Ignorant" out-of-towners spending summer holidays in the Tauranga area are sparking concern for the future of the region's shellfish population.
From November 2021 to January 12 this year, 33 people were caught collecting shellfish illegally.
During the same period in 2020/2021 there were 32 people and in 2019/2020 there were 34.
Ministry for Primary Industries district team leader of fisheries compliance Jodie Cole said fishery officers usually observed "a slight increase" in shellfish offending during summer.
In September, three people were apprehended. That number jumped to 10 in October, then nine in November, and 16 in December.
"As a popular holiday destination, our shellfish beds do come under some increased pressure," Cole said.
People needed to "be aware of the rules and stick to them".
Cole said it was crucial people checked local fishery rules when collecting shellfish from unfamiliar areas.
Dr Phil Ross, a marine ecologist at Waikato University, said he was concerned about the Bay's shellfish population.
Environmental factors such as pollution and climate change were already depressing shellfish numbers and excessive collections only made things worse.
"If we then overharvest them and bring them down, that's when they're gonna crash."
Collectors often took the largest shellfish, considered the most prolific breeders, which lessened the chance of successful reproduction.
Ross was particularly concerned about mussels and paua as the Bay had very few rocky reefs, making them easily overfished.
Poaching could be caused by "just not knowing the rules … or it could be intentionally going out to overharvest or collect in a protected area".
Paua and crayfish were "really high-value species" and attracted organised poachers, he said.
Ross said both a long-term approach to tackling climate change and more immediate changes such as reducing plastic use and creating protected areas on surf beaches would help to make a difference.
"You want to [protect] a portion of every type of habitat ... not only does that remove that stressor, but it helps us understand what's going on."
People should "only take what you need for a feed".
Ngāi te Rangi's Reon Tuanao said such collections were because of illegal and ignorant behaviour.
"Some people make mistakes. Some people go in quite ignorant, as opposed to arrogant … people coming from out of town and not knowing the regulations.
"There needs to be a bit more push on the awareness and education side of things."
Tuanao said illegal shellfish collection had an "immense" impact from a cultural perspective.
When his marae held events such as tangihanga, providing local delicacies had great spiritual significance.
"If the kai's not there, we're unable to practice that culture.
"It has an impact on what we see as our mana when we're unable to do that."
Illegal collectors "just rip bust and leave it bare", he said.
"It takes a long time for it to recover. It's not the right thing to do. It's not the way we should be treating our moana."
Wanānga (serious discussion) was needed, he said.
"Everyone's got to take ownership, and take katiakitanga-ship (guardianship).
"Oranga taiou, oranga tāngata - if the environment is healthy, then so are the people."
Te Arawa Fisheries chief executive Chris Karamea Insley said there were many more people coming into the Bay, out to the beach and gathering food.
His concern was "making sure our fisheries are sustainably managed".
Each iwi had a designated person with authority to issue permits for shellfish collection, and they "encourage our people to get permits to go out and do food gathering".
Tuanao also encouraged people to observe rahui when imposed.
Te Arawa Fisheries were working with many expert research organisations to develop "the science that will enable us to ensure that we preserve every one of those populations [of kaimoana] in perpetuity".
Ngāti Ranginui and Ngāti Pukenga were contacted for comment.