Dutch yellowtail: the super-sustainable, sashimi-grade fish coming to home kitchens

by Great British Chefs 22 July 2021

Sashimi-grade fish are some of the most exciting to work with both in the professional and home kitchen – but the sustainability credentials behind them can be pretty poor. The Kingfish Company is changing that with its hyper-environmentally-friendly yellowtail farm in the Netherlands. We take look at what the company’s doing differently and why the species itself is such a joy to cook and eat.

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The past ten years have seen sustainability become one of the most important factors in sourcing high quality produce, particularly in regards to fish. Tuna is becoming increasingly endangered, which means more and more chefs and home cooks are turning to alternatives. Yellowtail is still a relatively obscure fish in the UK but until recently fell into this same camp, often caught wild or farmed offshore around Australia. However, The Kingfish Company’s radical approach to super-sustainable farming in the Netherlands has changed that completely. This environmentally friendly producer uses an innovative system when farming its Dutch yellowtail to ensure the process is sustainable at every level and still produces the highest quality product.

Also known as kingfish or hiramasa, yellowtail is found predominantly in the Pacific Ocean and has become increasingly popular as an alternative to endangered species such as bluefin tuna and swordfish. However, over the years, the species has become associated with unsustainable farming practices, which not only lead to environmental issues such as water pollution, but also to a compromised product in terms of quality. Typically, yellowtail farms not only relied upon wild-caught fish for feed and (in some cases) used antibiotics and hormones to grow the fish in overcrowded tanks, but would also pump unfiltered, contaminated water back into the sea. This unsustainable style of yellowtail farming was regarded as standard until The Kingfish Company changed the game with its ground-breaking, ultra-renewable Zeeland farm based around a recirculating aquaculture system (or RAS).

The company was founded in 2015 by CEO Ohad Maiman, who saw the potential of RAS technology but felt it hadn’t been given a fair chance to prove itself. ‘What struck me when I first heard about RAS was that it’s like a greenhouse for fish,’ Ohad explains. ‘It has similar advantages in that it’s a controlled environment with optimal conditions, and it essentially gives you the ability to produce food where it is not otherwise possible.’ Despite other smaller RAS farms having failed in the past, largely due to the technology not being fully developed and companies having to cut costs, Ohad felt that, if done right, with sustainability put at the forefront, it had the potential to change the way that fish was farmed.

The Kingfish Company's farm in Zeeland, The Netherlands, might be large – but by using 100% renewable energy and ticking every sustainability box it can, the impact it has on the environment is minimal

Rather than being reared in the sea, Dutch yellowtail are grown in large land-based pools as part of a recirculating aquaculture system (RAS)

Working with co-founder and RAS expert Kees Kloet, they decided that yellowtail was the perfect fish to build the company around. ‘We had several pilots to figure out the needs of the yellowtail kingfish’, says Ohad. ‘It’s often imported from Japan and is a high-value species, which is important because this technology is quite an expensive way of farming fish.’ After years of development Kingfish Zeeland opened in 2018, boasting exceptional sustainability credentials and aiming to challenge people’s perception of traditional aquaculture.

First at foremost, the company wanted to demonstrate that the farm could be run in an environmentally friendly manner. ‘In the Netherlands we operate on 100% renewable energy, which is a bit more costly than standard energy but it’s all about our mission statement and our values. That’s why we decided to go the extra mile with a few choices.’ When it comes to the seawater used in the system, not only is it cleaned on the way in but on the way out too. This means that any debris and feed floating in the water is filtered out before it’s discharged, and the waste is used either as fertiliser or bio gas. The use of sea water in the system also means there’s no limitation on how often the water can be replaced, so 40% of the water in the system is exchanged daily, which leads to healthier fish and ultimately a better tasting product.

The perfect conditions inside the RAS system also mean that the Kingfish Company can grow its yellowtails without any antibiotics or hormones in the water. Ohad didn’t want to cut any corners when it came to feed either. ‘In some traditional farming practices, feed is constantly being degraded in terms of nutritional values,’ he says. ‘That’s why we opted to go for the highest-grade feed available, which mimics, as close as possible, what fish would get in the wild, and results in relatively high levels of omega three and the ideal fat levels. We’re now looking into reducing the use of marine ingredients by using sustainable alternatives like insect-based fish meal.’

From a chef’s perspective, however, how does The Kingfish Company’s Dutch yellowtail compare to other, more traditionally farmed fish? Mark Dixon, head chef of the King’s Arms in Fleggburgh, was one of ten European chefs brought over to Kingfish Zeeland to see the system in full flow when it first opened. He’s been an advocate for the Dutch yellowtail ever since. ‘I was a bit unsure when I first heard about it if I’m honest,’ Mark explains. ‘We were always told not to use farmed fish because the flavour isn’t always there. I just didn’t think it could be as good as wild fish caught out of the sea. The first time I saw the operation, I was blown away by the size of the tanks – it just wasn’t what I’d pictured. However, as much as we always want to be as sustainable as possible, the key element for any chef is the flavour; does it taste as good as a normal fish? And this fish definitely does. It’s absolutely beautiful flavour-wise.’

The size of Dutch yellowtail means it's perfect served whole for people to share at the table

It's also very popular in Japanese cuisine, where it can be served as sashimi with a variety of condiments and seasonings

Yellowtail nigiri

by Hideki Hiwatashi

Hamachi usuzukuri – yellowfin sashimi with truffle and pepper sauce

Hamachi usuzukuri – yellowtail sashimi with truffle ponzu

by Hideki Hiwatashi

Dutch yellowtail is an incredibly versatile fish, suited to all manners of different styles and methods of cooking, from classical French dishes to modern Asian cuisine. The firm texture of the fish, which Mark likens to that of swordfish, allows for it to be served both raw and cooked, while its mild taste means that it can also be paired with a variety of different flavours. ‘We recently used it in a tartare because it’s so good that you don’t want to mess around with it too much,’ says Mark. ‘It works brilliantly with fresh flavours like apple and avocado. My favourite way to cook yellowtail is actually with a blowtorch so you can get that barbecue flavour coming through whilst keeping that medium-rare texture. When I cooked it like that, I found it went beautifully with flavours like sesame, soy and pickled ginger. The size of the fish also means you can do everything from baking it whole to grilling and smoking it.’

In creating a product which is as sustainable and high-quality as Dutch Yellowtail, The Kingfish Company has proved that there’s a bright future for RAS farming. Not only can the fish now be found in a number of top European restaurants but it’s making its way into home kitchens via Whole Foods shops (and the company will soon be launching a direct-to-consumer site too). Meanwhile, The Kingfish Company is set to open a second RAS site in Maine soon, bringing its yellowtail to North America for the first time. Whether you’re keen to cook sashimi-grade fish at home that has some of the highest sustainability credentials around or simply want to work with a new, relatively unknown species, yellowtail is set to become an increasingly common sight – and may just help to take the pressure off more endangered species while at the same time.

To learn more, visit the-kingfish-company.com.