New insights to breed native fish

However, the only species of fish that is farmed here at the moment is king salmon. It's hoped that by being able to farm native fish such as snapper and trevally as well, consumers will be provided with greater choice of locally-produced seafood.

This is why Dr Maren Wellenreuther is leading a team of scientists at Plant & Food Research's Nelson facility to breed species of fish suitable to farm in our surrounding ocean waters.

Now in its fifth year, the accelerated breeding programme has granted researchers new insights from a breeding perspective, according to Wellenreuther.

"While recreational and commercial fishers are well acquainted with snapper and trevally, not much was known from a breeding perspective. The first thing we did was bring fish into our facility and get to know the really basic stuff about them.

"What temperature do they need? What do they need to reproduce and thrive?"

With a strong background in fish biology, ecology and genetics, Wellenreuther says she has been able to learn a lot about how to run a breeding programme from her colleagues since joining the team.

"Scientists at Plant & Food Research have huge knowledge when it comes to plant breeding -such as apple, kiwifruit, and pear.

"Because I was new to breeding but knew all about fish, it was a perfect marriage bringing those skills together."

Much like any farm animal, the breeding programme at Plant & Food Research aims to produce fish that grow well, but other factors are important too.

The team is especially focused on the aim of 'future-proofing' species against disease and more general threats such as climate change.

"Improved growth rate is our main goal, but we are also trying to select them for hardiness and for temperature tolerance."

With much of the available coastal space for aquaculture already being used for mussels, oysters and salmon, it's likely that new species will be farmed further out to sea, in what's known as ocean open aquaculture.

As part of their broader aquaculture research programme, Plant & Food Research is developing technology that will allow these farms to be mobile, moving around the ocean to deliver optimal temperatures for their fish.

Wellenreuther says while breeding programmes usually take a long time to show progress – snapper take 3 years to grow to the age where they can reproduce, up to 4 years for trevally – improvements are already being seen in the latest generations of fish spawned.

"We did some trials to compare our selected fish to wild snapper, and we found that the growth rate increased by 30 per cent and the survival rate was much improved.

In the wild snapper, out of 600 fish we had 70 mortalities, but with the selectively-bred snapper we had only one.

So if you compare that, it's a massive difference."

Compared to other animals, and even plants, breeding fish creates its own challenges. With hundreds of fish in a tank, it's harder to tell the mother and father of any given snapper, so DNA testing is done.

This not only helps to establish which parents produce faster growing offspring and other desirable traits, but allows the scientists to avoid inbreeding in subsequent generations.

In addition to DNA testing, the breeding team have been developing new methods of identifying and measuring individual fish. It's the same sort of facial recognition technology used to unlock smartphones, but a lot more challenging when the subjects are fast-moving, underwater, and almost identical to the untrained eye.

"The possibilities are exciting, but only if we can take our research and make it real. That means it's really important to us to work with Māori and the industry to identify new aquaculture opportunities that create economic growth and new employment opportunities that are sustainable in the long term. "

Wellenreuther hopes this programme will not only result in adding snapper and trevally to the species already being farmed successfully in New Zealand, but will also develop a 'toolkit of knowledge' that can be rolled out to other species in the future.