Lack of UV light harming tuatara

Some New Zealand tuatara facilities have been inadvertently harming their endangered charges by enclosing them without sufficient light, new research shows.

Without full-spectrum lighting, tuatara can suffer nutritional secondary hyperparathyroidism (NSHP), which causes bones to break and other painful conditions.

Ultraviolet (UV) light produces vitamin D, which helps the bones absorb calcium.

Research published by Massey University in the January issue of the New Zealand Veterinary Journal shows four of the 18 tuatara facilities examined in New Zealand (five overseas zoos keep tuatara) were using ineffective UV light sources and others were not supplying enough.

"The results of this study showed a significant proportion of tuatara in New Zealand are not provided with sufficient access to ultraviolet B light for the synthesis of vitamin D, which may acerbate the problems created by a poor diet," the study said.

"Furthermore, a clear relationship was demonstrated between the availability of light and the historical risk of NSHP for animals kept indoors."

It does not mention facilities by name or whether the problem had led to deaths.

Tuatara Recovery Group captive-management co-ordinator Barbara Blanchard, of Wellington, who helped with the study, said Christchurch's Orana Wildlife Park had been the first to "pick up" the problem, which was then identified in a North Island facility.

All facilities had been told to ensure their tuatara had access to UV light equivalent "to what you see on a cloudy day in New Zealand".

She said more research on the optimum UV light for tuatara was needed.

Orana head of native species Tara Atkinson said the research would save lives but had come too late for the two "babies" that died at the park about three years ago.

"Their bones were not up to it. They were too soft to support growth," she said.

The youngsters were the result of "accidental breeding" and had been kept indoors because of the Christchurch weather.

The park had learnt from the experience and now had a purpose-built indoor facility that provided adequate light, she said.

Willowbank Wildlife Reserve head of native species Nick Ackroyd said the park had an indoor group of tuatara and one outdoor.

Recent tests had shown a UV light used for the indoor group was not producing enough UV and it had been changed.

- © Fairfax NZ News