KEY POINTS:
In the first of a regular series on where our food comes from, salmon farmer Richard Miller of Regal Salmon educates Jennie Milsom in the secrets of salmon farming and how the fish make their way from Marlborough to your menu.
Regal harvests 1.5 million salmon a year. Salmon seems to be everybody's fish of choice these days - just how big is salmon farming?
Regal Salmon harvests about 1.5 million a year - that's around 500 tonnes of salmon a month - and that's growing by 10 per cent each year, thanks to the domestic market taking off and international demand. What we harvest and process today can be in Japan within 24 hours.
Just how many salmon are in each cage?
As farmers, it's up to us how many salmon we put in each cage. Having too many salmon in a cage is an inefficient way of farming, though, as it reduces the rate at which they grow. The only restrictions we have are the number of salmon that can be discharged from the farms and we must abide by strict feeding constraints.
Do those sneaky salmon ever escape their cages?
Not really. Salmon are a bit like sheep and tend to follow each other around. Though we do have a problem with seals breaking into the nets and eating the salmon.
What makes one salmon taste better (and not just to those seals) than another?
A lot of it's down to the texture. Salmon need a good current to swim in and the water needs to be at the right temperature, around 13-14C - any colder and they don't grow, any hotter and they die. They also need monitoring constantly so we must have access to them - we have underwater cameras and a team of specialist divers who inspect the cages every day, making sure all is as it should be. The flesh should be a deep orange colour and flake up nicely when cooked.
How fatty are salmon?
They should have a fat content of 22 per cent. The flesh should be firm and oily without being greasy and have distinctive ribbing - that's the white protein which runs throughout the flesh.
What are the fish fed on?
High-protein, high-fat fishmeal pellets made from an anchovy-type fish. Two thousand tonnes of whole salmon will get through 3500 tonnes of feed. We feed to satiation - over-feeding them would be costly and if they're under-fed they won't grow enough. Also, if salmon grow too quickly it stresses them out and the resulting flesh will be too fragile in texture, so it's a fine balance. We're constantly monitoring the feed to achieve the most efficient results.
What's the average life expectancy of a farmed salmon?
Between 18-30 months, which includes six-12 months of freshwater rearing until their weight gets up to around 100g, then they're moved to sea cages. We harvest year-round with peaks in November and December.
What happens to salmon that don't make the grade?
Every salmon is harvested - even those smaller than average - and used in one way or another. We're also working on ways to extract omega-3 from salmon.
What is your top tip for preparing salmon?
Always wait at least 24 hours before filleting a salmon after it has been caught, as the flesh needs time to relax. If you fillet it straight away, the flesh is likely to tear.
