New Zealand’s vast marine territory, including its Exclusive Economic Zone (EEZ), supports a robust and diverse population of sharks. Managing one of the largest ocean areas in the world, covering over four million square kilometers, the EEZ creates a mosaic of habitats from tropical waters to the sub-Antarctic. This extensive range supports a significant number of shark species, confirming that these ancient predators are an integral part of the nation’s marine ecosystem.
Shark Presence and Biodiversity
The waters surrounding New Zealand host approximately 112 species of cartilaginous fish, including sharks, rays, and chimaeras. Scientists estimate that over 70 of these are true shark species, showcasing rich biodiversity. This high number includes species ranging from small, bottom-dwelling dogfish to the world’s largest filter-feeders and apex predators.
The shark population is categorized based on preferred habitats within the EEZ. A large proportion consists of deep-water sharks inhabiting the continental slope and oceanic depths. Other groups include coastal species, frequently observed in shallower inshore waters, and highly migratory pelagic species that traverse the open ocean.
Most sharks in New Zealand waters are generally harmless to humans, often being small or preferring habitats away from popular swimming areas. Their diversity demonstrates the varied ecological niches available, from the surface layers to the deep abyssal plains.
Notable Species in New Zealand Waters
Great White Shark
The Great White Shark (Carcharodon carcharias), an apex predator, is one of the most recognizable species, found throughout the EEZ north of the Campbell Island latitude. Adult females can reach lengths of up to 6.4 meters and weigh over 1,900 kilograms. They are characterized by a slate-grey dorsal surface and a contrasting white underside, a coloration that aids in camouflage.
Great White Sharks are opportunistic hunters. Adult diets include larger prey like marine mammals, such as seals and sea lions, while juveniles primarily feed on fish and smaller sharks. This species is classified as nationally endangered in New Zealand and has been fully protected since 2007.
Bronze Whaler
The Bronze Whaler (Carcharhinus brachyurus), also known as the Copper Shark, is commonly encountered in coastal areas. These sharks average between 1.5 and 2.5 meters in length. They possess a distinctive bronzy-grey to olive-green coloration and typically lack a ridge between their two dorsal fins.
Bronze Whalers are often seen in shallow waters during the summer, including bays, harbors, and surf beaches, especially around the North Island. They primarily feed on schooling fish, such as kahawai, and are one of the most abundant large shark species near the coast.
Blue Shark
The Blue Shark (Prionace glauca) is a highly migratory, pelagic species found across the entire EEZ, often in deep water or over the outer continental shelf. They are easily identified by their slender bodies and distinctive indigo-blue coloring on their back, built for endurance. Blue sharks are one of the most abundant large sharks globally.
Basking Shark
The Basking Shark (Cetorhinus maximus) is the second largest fish in the world, with the largest measured specimen in New Zealand reaching over 10 meters. Unlike predatory species, Basking Sharks are filter feeders that consume zooplankton, swimming slowly with their enormous mouths open. Though historically seen in large schools off the East Coast of the South Island, sightings have become infrequent.
Geographical Distribution and Migration
The distribution of sharks in New Zealand is not static, as many species undertake seasonal migrations driven by temperature and food availability. Highly migratory Great White Sharks aggregate seasonally around southern locations, such as Stewart Island and the Chatham Islands. From March to September, many embark on long-distance migrations to the tropical Pacific, traveling as far as Australia, Fiji, and Tonga.
These movements cover significant distances. Sharks spend several months in the southern aggregation sites before heading north to warmer waters for the remainder of the year. Juvenile Great Whites are more commonly found in the warmer, shallower coastal waters around the top half of the North Island.
Bronze Whalers also exhibit seasonal movement, entering shallow coastal waters and estuaries during the warmer summer months. This shift occurs as they follow schools of prey fish and use sheltered areas for pupping. During the cooler winter, these sharks generally move further offshore into deeper waters.
Blue Sharks, being oceanic, are found throughout the EEZ, but their presence near the coast is limited to areas where the continental shelf is narrow. They are most abundant during summer and autumn, corresponding with a general southward migration as ocean temperatures rise.
Minimizing Encounters and Protecting Marine Life
While sharks are a natural part of the marine environment, simple measures minimize the risk of human interaction, especially during summer when coastal species are numerous. It is advised to avoid swimming during periods of low light, such as dawn and dusk, as many sharks are nocturnal hunters. Swimmers should also avoid areas with obvious feeding activity or where fishermen are disposing of fish offal.
To reduce the chance of an encounter, people are encouraged to swim between the designated surf lifesaving flags at patrolled beaches. If a shark is sighted, remain calm and avoid excessive splashing, which can attract attention. Maintaining eye contact with the animal can sometimes deter an inquisitive shark from approaching.
Protecting New Zealand’s shark population is a conservation priority, with several species granted full protection under the Wildlife Act 1953. The Great White Shark has been fully protected since 2007, making it illegal to hunt, harm, or possess them. This protection also extends to:
- The Basking Shark
- The Oceanic Whitetip Shark
- The Smalltooth Sandtiger/Deepwater Nurse Shark
If any protected species are accidentally caught in fishing gear, they must be released immediately and unharmed, with the capture reported to the Department of Conservation. This legal framework recognizes the importance of these predators in maintaining healthy marine ecosystems.