Sunday, June 16, 2024

Cameras reveal hidden depths of Kaikōura Canyon

The National Institute of Water and Atmospheric Research (NIWA) has used a deep-sea camera system to video the depths of the Kaikōura Canyon, providing fresh insights about marine life inside and outside Hikurangi Marine Reserve.

The Institute carried out the survey for the Department of Conservation (DOC) over a week in February. NIWA scientists operated the specialist Deep Towed Imaging System (DTIS) from their research vessel R.V. Tangaroa to video the deep seafloor of the marine reserve and surrounding area.

Hikurangi Marine Reserve lies off the coast south of Kaikōura township, extending offshore for just over 23 kilometres and covering an area of approximately 10,416 hectares. The reserve covers much of the base and some of the steep sides of the Kaikōura Canyon. The canyon is a food basket for the many whales, dolphins, seals and seabirds that Kaikōura is renowned for.

DOC Senior Marine Biodiversity Ranger, Jody Weir says NIWA’s deep-sea video equipment enabled monitoring of the 1,000-metre deep Kaikōura Canyon in Hikurangi Marine Reserve that otherwise wouldn’t be possible.

“DOC monitors marine reserves to better understand their marine ecology including the changes occurring because of their protection, with no taking or disturbance of marine life allowed,” said Ms Weir.

“The survey included some sections videoed previously by NIWA and some new sites from around the canyon and has provided some interesting initial observations. Fuller analysis and reporting of the findings will happen over the coming year or more.

“Importantly, the deep-water videos enable us to see and document changes to the seafloor since the November 2016 earthquake triggered an enormous amount of sediment to flow down and through the Kaikōura Canyon.

“Before the earthquake, the canyon was renowned internationally as a biodiversity hotspot with abundant fish species and very dense populations of seabed invertebrates – worms, sea cucumbers and urchins – in their thousands per square metre. These seafloor communities were smothered by the earthquake’s sediment flow, though monitoring by NIWA in following years has showed some recovery.

“This latest survey pleasingly found continued recovery of the seafloor ecosystem inside the marine reserve, with signs of abundant marine life again inhabiting the depths of the canyon.”

NIWA scientist, Dr Ashley Rowden, who led the NIWA survey, said, “one of the notable observations was a sponge garden with an associated community of sea cucumbers, ascidians, hydroids, anemones, other invertebrates, and fish on the northern edge of the canyon outside Hikurangi Marine Reserve”.

“We also saw a sparse community of soft corals, black coral, sea lilies and other species on the canyon walls in some places.” 

DOC and Te Rūnanga o Kaikōura are asking people to follow the rules. Disturbance, fishing, or taking of marine life in Hikurangi Marine Reserve is not allowed to protect its marine ecosystem.

“We want people to value and enjoy Hikurangi Marine Reserve for its incredible biodiversity and the opportunity it offers to see whales, dolphins and seabirds, and other sea life,” said Ms Weir.

“But it’s important that everyone does their part to allow its marine life to flourish, including no fishing of any kind.”

Anyone who sees people illegally fishing in Hikurangi Marine Reserve or other marine reserves is asked to report it to the DOC 24-hour emergency number 0800 DOCHOT (0800 36 24 68).

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