Almost daily since mid-September, shark warning signs have been posted by city lifeguards at Kaimana Beach because of white-tipped reef sharks swimming close to shore, feeding on schools of halalu (juvenile big eye scad).

Occasionally, fishermen standing at the water’s edge inadvertently hook a feeding shark. Mereck Pang said he snagged one Monday afternoon, and on Tuesday Fritz Dumalan hooked a 4- to 5-foot reef shark — small fry, he added, compared with the 14-footer that took his line two weeks ago.

Sharks cut the lines and free themselves, the fishermen said.

As for the many humans swimming and floating amid the baitfish, undeterred by the signs, lifeguards’ warnings — and the sight of the sharks, themselves — a Honolulu Star-Advertiser reporter observed fishermen taking care not to cast their lines around people Monday and Tuesday.

But Manoa resident Dale Moana Gilmartin said she’d felt threatened by fishermen the week before as she swam off Kaimana Beach.

“It was Thursday, right before sunset, and I was 30 feet from shore, and to get back I had to swim through baitfish schooling next to the Natatorium — some of the fish balls are so big they could fill a large living room,” she said, “when the fishermen started screaming at me, ‘Get out of there, you’re going to get hooked!’”

When she shouted back she was swimming through, and “we all have to share the water,” the fishermen started casting their hooks “10 inches from my head.”

The fishermen also entangled a canoe paddler in their lines by the Natatorium, Gilmartin said. “She was pulling the lines out of her hair.”

On Monday evening, fisherman Gordon Rivera, a Waikiki resident, said he’d witnessed quarrels between fishermen and swimmers, but things calmed down “about two weeks ago, when we were warned by DLNR (state Department of Land and Natural Resources Division of Conservation and Resources Enforcement officers).”

Since then, Rivera said, “We’ll let (swimmers) know about the fishing lines, ask them politely to please be careful.”

Rivera pointed out a monk seal diving in a dark bait ball on the Diamond Head side of the beach, where 10 fishermen stood on a rock jetty, casting their lines. “The seals just going for the fish we trying to catch, same as shark does.”

Two monk seals had appeared over the past two days, he said, and hauled up on the beach next to the Natatorium, which had been cordoned off to protect the endangered marine mammals.

Since fishermen could no longer stand casting at the water’s edge within the zone, it also protected swimmers in the area where Gilmartin had crossed paths with the fishermen’s hooks and lines.

On Tuesday, a sleek monk seal basked on the warm sand alongside the Natatorium, while three 4- to 5-foot sharks swam through dark shoals of bait.

Waipahu resident Shanalyn Dumalan sat on the sand near her three children as they frolicked at the water’s edge. Asked if she worried about the sharks, “Nah, not really, as long as I’m watching them,” she said.

“I mean, they’re on the shore,” she added.

Higher up in the middle of the beach, Diamond Head resident Ramona Ruiz said she hadn’t been worried until a reporter asked if she was.

Ruiz called her 9-year-old son out of the water, told him to be aware there were sharks and not swim far, and let him go back in.

Asked if people were safe from shark bites when a natural food source was so abundant, “There’s never no chance,” said Kim Holland, a shark and reef fish researcher at the Hawaii Institute of Marine Biology at the University of Hawai‘i at Manoa. “You’d have to say the risk is low, but it’s certainly not zero.”

Holland added the sight of sharks feeding close to shore was encouraging because “it shows that sharks are still quite common in coastal waters of Hawaii, even in urban areas like Honolulu.”

What Gilmartin found encouraging was that, in the more than 20 years she’s been swimming at Kaimana Beach, she couldn’t recall “ever seeing this many fish close to shore.”

She wondered if it showed “marine life returning to our beaches, (because they’re) less populated due to the pandemic.”

“As for why the school of halalu is close to shore, it could be a combination of the lack of people in the water (during recent COVID-19 beach closures) and/or predators feeding on the halalu pushing the school closer to shore,” said David Sakoda, a fisheries program manager at DLNR’s Division of Aquatic Resources.

But there have always been bait balls in summertime, he added, if not necessarily to such great extent.

“Besides at Kaimana Beach, there were also large schools of halalu at Ala Moana and Waikiki this year, so it seems to be a great recruitment year, but we are also hearing that the halalu did not show up in some of the usual places that they are normally fished,” Sakoda said.

Parts of Oahu’s south shore were once wetland/ estuary habitat providing a nursery area for halalu, which grow up into akule and move offshore.

“Once the halalu are gone, no more predators: no more sharks, seals, papio (young ulua, or jack), awa awa (milkfish),” Pang said. “Once they go, I don’t know what I’m gonna do.”

It seemed possible 2020 might be remembered as the year of a surge in fish off Waikiki and a plunge in tourists, until the halalu departed at their season’s end and tourist numbers began to rebound as the state eased restrictions.