All hands on deck needed to save Māui dolphins

Friday, 20 May 2022

Maui dolphins are amoung the rarest marine mammals in the world.

Elvisa van der Leden is the Taranaki regional conservation manager for Forest and Bird. She is also a Taranaki Regional Councillor.

OPINION: Fifty-four. That’s how few Māui dolphins we think might be left, according to the Department of Conservation’s latest estimates.

These iconic dolphins – miniature in size with round dorsal fins like Mickey Mouse ears – are on the precipice of extinction.

That’s why we must do everything we can to protect them, addressing all the threats these ‘Nationally Critical’ animals face.

Recently, the fishing industry called for the Department of Conservation to do more to tackle the threat caused by toxoplasmosis, a disease caused by a parasite found in cats.

Feral cats, and domestic cats, can spread toxoplasmosis through their faeces.

* Fishing industry calls for government to recognise toxoplasmosis as main threat to Māui and Hector’s dolphins

* The endangered Māui dolphin is a conservation priority – we shouldn’t let uncertainty stop action to save it

Forest & Bird backs this call – we understand the hard yards required to control feral cats on the ground – but putting more effort into cat control doesn’t mean it’s time to loosen fishing restrictions.

But let’s back up first: what is toxoplasmosis? It’s a disease caused by a parasite that can infect all sorts of warm-blooded animals, including humans and dolphins.

But while many animals can be infected, there’s one animal that is key to the reproductive cycle of the Toxoplasma gondii parasite: cats.

Eggs of the parasite end up in cat poo, and remain infectious for up to a year. They spread through the environment when cat faeces washes into waterways, or when it is flushed down the toilet, eventually ending up in our oceans.

Here, our precious Māui dolphins can become infected upon ingesting contaminated water or fish.

The parasite attacks the dolphin’s immune system and is particularly deadly to pregnant female dolphins, because of their already suppressed immune system.

The parasite can cause miscarriages – not just for dolphin mums, but also in human mums. That’s why pregnant women have to wear gloves when gardening, and avoid emptying the kitty litter tray. It’s serious stuff.

Addressing the threat of this nasty disease means addressing our feral cat problem.

Here in Taranaki, the local Forest & Bird branch has written to the Taranaki Regional Council asking for more funding for feral cat control and advocating for responsible cat ownership and management.

More boots-on-the-ground action is needed, with proper resourcing, to make a dent in the feral cat population.

And it’s not just the Māui dolphins that will benefit – more cat control would be a win for our native birds, lizards and insects too.

But Māui dolphins are like patients presenting to the Emergency Room with both a bleeding wound and a tumour.

We need to triage: stem the bleeding first, before treating the tumour. In the same way, we don’t want to leave our Māui dolphins vulnerable to the threat of fishing – which we can sort out quickly – while focusing on the tough malady to treat: the toxoplasmosis.

Māui dolphins live fairly close to shore, which means their home overlaps with places we like to fish (both commercially and recreationally).

This is a problem because they can get tangled in set nets and drown. The Department of Conservation states that “a significant number” of Māui dolphins have died as a result of entanglement in set nets. But the good news is that we can easily take action to reduce this threat – and we have.

Not using set nets in Māui dolphin habitat is a simple and effective way to protect these pint-sized dolphins from one of the threats they face.

No one is saying “don’t fish at all.” It’s simply about where and how we fish.

Plus, the world is watching us. There’s a growing demand for sustainable seafood that doesn’t threaten dolphins.

In 2020, New Zealand faced a possible trade ban on fish exports to the US, because we weren’t doing enough to protect Māui dolphins.

At the time, Government officials warned that $200 million in fish exports were at risk. Protecting Māui dolphins from dying in fishing nets is in the best interest of the fishing industry nationwide.

The fishing industry, environmental organisations and iwi have already come together to stop seabed mining in Taranaki – another significant threat to Māui dolphins.

Now it’s time to tackle the tricky threat of toxoplasmosis, with more urgent support needed from Government to control feral cats.

Now is not the time to soften fisheries restrictions, and we are heartened to see that the Department of Conservation is remaining staunch on this.

Our 54 remaining Māui dolphins need us to take every action possible to give them a chance of survival.

Elvisa van der Leden is the Taranaki regional conservation manager for Forest and Bird. She is also a Taranaki Regional Councillor.