We now know there’s a predator swimming in Hawke’s Bay waters that can grow up to 12 metres long.

So with a smattering of recent shark sightings culminating on Wednesday in the daring rescue of a rare juvenile basking shark (Cetorhinus maximus) on Napier’s Marine Parade beach, the age-old question for those living in coastal areas heading into summer remains: “Is it safe to go back in the water?”

Generally, the answer is yes, but perhaps it would be wise for swimmers and beachgoers to be a little bit careful this summer, one marine expert says.

The basking shark that beached on the Napier shoreline was saved thanks to the help of police, beachgoers and tourists.

A shark stranding on Napier's coast on Wednesday was "rare", but more shark sightings are expected in Hawke's Bay this summer.

A mature adult typically grows to between 7-8m in length, with a maximum length of 12.2 metres.

The Department of Conservation’s technical adviser for protected fishes and marine reptiles, Clinton Duffy, said strandings were unusual for sharks, let alone the basking species, but that didn’t mean they aren’t in the water this summer.

“The species used to be very common in coastal waters around parts of the South Island during late spring and early summer, but largely disappeared in the mid-late 1990s,” he said of the basking shark.

“This is the second-largest species of fish after the whale shark (Rhincodon typus) – also found in NZ waters, also a protected species,” Duffy said.

“A variety of sharks are present around New Zealand throughout the year, with the species and numbers of sharks found in any particular area usually changing seasonally.

“So, whenever you’re in or on the water, there is a chance you could encounter a shark.”

Last year, Duffy said he was aware of 16 unprovoked attacks on swimmers and surfers in New Zealand waters that occurred between 2012 to 2021 – two of them fatal.

In data provided to a coroner, Duffy said he had recorded 61 unprovoked shark attacks on swimmers and surfers from 1852 through to early December 2020. Ten of those attacks were fatal.

“Although the vast majority of encounters with sharks are uneventful, any shark over 1.8m long should be treated as being potentially dangerous,” he told Hawke’s Bay Today.

“Even species that do not feed on large prey and pose no risk of attack can cause injury if they are injured or harassed.”

Duffy said what caused the juvenile basking shark to strand on Wednesday was unknown. A large dead porbeagle shark was also discovered on Mohaka Beach in September.

“The most common cause of sharks being found on beaches is because they have been discarded or dumped there by fishers.

“On very rare occasions, toxic algal blooms or disease can result in sharks becoming disoriented and accidentally beaching themselves. Sharks will also swim into very shallow water, risking becoming stranded, to avoid killer whales.”

People in Hawke’s Bay could likely expect an increase in sightings of large pelagic species, particularly blue sharks, mako, bronze whalers and smooth hammerhead sharks heading into summer, Duffy said.

“All of these species can occasionally be found close to shore, but bronze whalers and blue sharks are the species most often seen or caught off Napier’s beaches.

“Great whites and sevengill sharks are present in Hawke’s Bay waters all year round, but great whites tend to be more common from May to November.”

Duffy encouraged people to aid conservation efforts of endangered shark species by doing things like adopting friendly fishing methods and carefully disposing of rubbish and unwanted fishing gear.

People could also educate themselves on the 113 sharks and rays found in New Zealand and report sightings of protected species to DoC at [email protected] or on 0800 DOCHOT (0800 362 468).

Mitchell Hageman joined Hawke’s Bay Today in late January. From his Napier base, he writes regularly on social issues, arts and culture, and the community.