Source: Radio New Zealand
Stewart Hawthorn (left) and hatchery manager Hagen Kocksch remove the eggs from a female salmon. RNZ/Anisha Satya
Making salmon babies is like mixing a potion.
You take some eggs, add milt, and stir them around in a bucket – at least, that’s how the Akaroa King Salmon hatchery team do it.
As simple as it sounds, getting spawning day right is crucial for the business, chief executive Stewart Hawthorn said.
“From this hatchery, we support 75 jobs, a turnover of more than $35 million; $20 million of that is export earnings for New Zealand.
“It’s critically important for us.”
Akaroa King Salmon chief executive Stewart Hawthorn. RNZ/Anisha Satya
Follow Country Life on Apple Podcasts, Spotify, iHeart or wherever you get your podcasts.
The Waiau hatchery was first set up in 1987, diverting water from the Rotherham Stream to support raising small fish.
“Originally the idea was that they’d grow, sort of, plate-sized salmon for people to buy and eat,” Hawthorn said.
It was purchased by Akaroa King Salmon in 2023, which now uses it to hatch eggs and raise fish to a smolt stage.
After that, the fish are transported to Akaroa Harbour and ocean-reared for 16 months
“They spawn in freshwater, so you have to start them in freshwater, and then you finish growing in the sea,” Hawthorn said, “So that’s what we replicate when we do it here.”
New technology at the hatchery ensures there are always fish in the tanks, like a water chilling system for egg storage.
Some recently harvested King Salmon eggs – they’re very delicate at this stage. RNZ/Anisha Satya
“We can cool down the egg temperature. That means some of the eggs from this [spawn] will take a lot longer to develop… so we can spread out our harvests, effectively.”
Other additions help improve water quality and aeration, which help keep the fish calm.
This year, the hatchery is rolling out a special breeding programme, focused on increasing genetic diversity.
Akaroa Salmon hatchery manager Hagen Kocksch. RNZ/Anisha Satya
“Those are ‘families’ we are creating,” Hatchery Manager Hagen Kocksh said.
“We know the pedigree of those fish, and we have genotyped them, so we know [their] specific characteristics.
“Later on, we will focus on traits, genetic traits, like growth, resilience, temperature tolerance.”
Headed by the Cawthron Institute, the programme aims to build tastier fish and ensure there are King Salmon around to be eaten in the future.
Advanced technology helps in some ways – but when it comes to actually harvesting and fertilising eggs, human hands make light work.
Female fish are checked by hatchery staff for ‘ripeness’, or whether the eggs are loose and ready for release, by a feel of the belly.
Ripe fish are euthanised and the eggs released into a bucket, aided by some pressure from an air pump.
The male fish are essentially ‘milked’- given a light squeeze – to release their milt into individual containers.
Akaroa King Salmon hatchery assistent manager Henry Wilson examines fish milt to determine which males have the best chance of producing high quality fish. RNZ/Anisha Satya
And then, like a potion, the two are mixed together.
Akaroa King Salmon broodstock – breeding fish. RNZ/Anisha Satya
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.
– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand