The most common shark around the Northland coast is the bronze whaler. Photo / Supplied
The most common shark around the Northland coast is the bronze whaler. Photo / Supplied
Warmer waters are bringing sharks closer to land this summer, as Northlanders' sightings of sharks increase.
Shark sightings typically rise in summer as the creatures migrate to warm waters and beachgoer numbers increase, but studies released this week show ocean temperatures worldwide have hit the highest levels ever recorded, forthe third year straight.
The heating of oceans, which the Advances in Atmospheric Sciences study attributes to increases in greenhouse gas levels, has pushed sharks to swim in waters that were previously too cold for the species.
This comes as no surprise to Claudia Sánchez, who was fishing for the first time in Northland's Rangaunu Harbour near Rangiputa when her kingfish catch turned into a battle with two large sharks.
"I felt this really strong tug on the line and I thought it was the kingfish. But I almost fell into the water, so my friend had to hold on to my waist and then we saw the sharks."
The incredible encounter, captured on video, shows two sharks, three to four metres long, fighting over the kingfish on Sánchez's line.
"I was on the boat with my friend and his dad, they're very keen fishermen. They've never seen anything like that before in their lives."
Claudia Sánchez was fishing for kingfish in Northland when she encountered two sharks. Photo / Supplied
She said the encounter happened only 10 minutes from shore, where people were swimming.
Sánchez lives in Auckland and was in Northland staying with friends who had already spotted a shark the day before, when they went diving for scallops.
Sánchez suspects she wasn't the only person who lost a fish to a shark that day.
"A lot of people were just catching fish and then just losing it, so maybe it was just sharks that were eating [them]."
"It was the catch and a loss of a lifetime," Sánchez said.
Mangawhai Surf Life Saving senior lifeguard Tony Baker said he thinks they are "definitely seeing an increase in big-fish activity".
"At least three or four people that I know have had quite close encounters with bronze whalers, they're becoming very astute with the sound of the spear, so they know when the gun was being fired ... they know there's food there."
Baker said the intelligent animals often learn popular fishing spots.
"If you can taste salt in the water there's probably a shark nearby."
Increases in shark sightings do not indicate the recovery of the threatened species, in fact, sharks' presence in popular fishing areas may point to desperation for food.
Reports of waters warming due to human-induced climate change come the same week as the National Institute of Water and Atmospheric Research (Niwa) announced that 2021 was New Zealand's hottest year on record.
The most common shark around the Northland coast is the bronze whaler. Photo / Supplied
Beaches aren't always closed if there is a shark in the water - Surf Life Saving New Zealand's official policy is that the shark sighting must be a "clear and present risk" to the swimming public.
"Clear and present risk" includes direct contact with swimmers and the animal being noticed by the public resulting in a possible panicked response by fleeing swimmers.
How long the beach will be closed in the event of the shark sighting depends on what beach you visit this summer, as it's at the discretion of the patrol captain.
Ruakākā Surf Life Saving Patrol captain Imogen Moore said she errs on the side of caution.
"Our policy is any shark sighting and we're closing the beach.
"If we see a shark and we think it's going to be a threat to the public, we're closing it for an hour since the last shark sighting by a lifeguard."
Moore said it is hard to tell if there have been more sharks sightings this year, but sightings can often cluster in one week.
"In the last four weeks, I think we've closed the beach maybe three times."
Moore understands that seeing a shark in the ocean is frightening, but she said it shouldn't come as a shock to Northlanders swimming in the creatures' habitat.
"The ocean is where they live, it's their home and we're in it."
Whangarei Heads Surf Live Saving Patrol captain Elise Troy closes the beach if a shark is sighted. Photo / Tania Whyte
Whangārei Heads Surf Life Saving Patrol captain Elise Troy said shark sightings can come in clusters over summer, often correlating with higher water temperatures.
"At the start of our summer, we did have a good amount of sharks pop up. But in the past few weeks, surprisingly, we haven't actually had many."
Swimmers at Whangārei Heads can expect the beach to be closed for at least half an hour in the event of a shark sighting, said Troy.
"Our protocol is to cross the flags for 30 minutes and keep an eye out [to see] if it's still there. Then we continue to cross the flags, but if we can't see it, we reopen them and we just advise swimmers not to swim, but we can't stop them from swimming."
Department of Conservation marine scientist Clinton Duffy said sharks are always sighted more frequently in summer for a number of reasons.
"Well, this time of year you've got the combination of sharks that come inshore to breed and feed ... then you've got the annual increase of people going to the beach and going fishing, going diving. So those two factors combine to result in an increase of shack reports at this time of year.
"As far as I'm concerned there's been the usual number of shark sightings for this time of year."
Duffy says despite the fact Northlanders are encountering sharks, there's not "plenty of fish in the sea".
"If anything there are fewer sharks in the water today than were last year because of fishing.
"Shark populations are quite vulnerable to fishing pressure."
Seven species of shark are protected under the Wildlife Act 1953:
Great white shark/white pointer/mangō taniwha Oceanic whitetip shark Basking shark/mangō reremai Whale shark Smalltooth sandtiger/deepwater nurse shark Spine-tailed devil ray/giant devil ray Oceanic manta ray/giant manta/Te Whai Rahi
It is an offence to hunt, kill, disturb, possess or trade these species. Accidentally catching a protected shark or ray and releasing it immediately is not illegal, but the event must be reported to DoC.
Sightings or captures of these species can be reported to DoC: sharks@doc.govt.nz or 0800 DOCHOT (0800 362 468)
