(Long read, ten minutes)

Everybody loves prawns. Even the most ardent fish-eating fuss pots buckle their aversions when it comes to a prawn. Salty-sweet, with tender meat there are few snacks that beat a pint of fresh prawns and a dollop of firecracker mayo to dip.

And when we say everybody loves prawns, we mean everybody as prawns are the most valuable fisheries product in the world, equating to over $28 billion in global trade each year, roughly a fifth of the world’s total seafood value. 

Us Brits consume over 50,000 metric tons of prawn each year alone, making it the country’s favourite shellfish by far. But when it comes to eating them it’s exceedingly important you know your prawns, the right prawn is one of the greatest delicacies you can eat, while the wrong prawn comes with such a rostrum of human and environmental challenges, that their naturally sweet flavour will do little to mask the sour taste left in your mouth.


Here in the UK the term prawn is used to describe pretty much anything from the tiny 20p sized sandwich filler to the meaty behemoths you might sling on the barbie.

What we’re actually talking about is a variety of different species and sub-species from a multitude of various climates and geographies.

The key distinction for the conscientious seafood eater to know is whether what you’re eating is a warmwater prawn, cold water prawn or a shrimp.


In US vernacular the term shrimp is generally used to describe any smaller prawn. While this is probably better than our all-encompassing prawn-generalisation, it too is not strictly accurate, as a shrimp is in fact any entirely distinct species. Often when you see reports from the US talk about shrimp, they’re actually talking about prawns.

So, what is a shrimp? Well, yes shrimp are generally smaller, but they are also distinguished by their shells. Shrimp bodies are encased in a sort of accordion shell, with a soft membrane between each segment, this makes them exceptionally agile and super flexible.

The prawn, by contrast, are made up of overlapping segments of thick cartilage – somewhat like the armour of a medieval knight. Much like King Arthur, or Sir Lancelot, dressed in full regalia the prawn is more restricted in their movement than their yogic cousins. To remember which, is which is simple, for shrimp think tiny, agile, yoga-experts, while prawns are heavily armoured warriors of the realm.

Perhaps we call every prawn-like thing we eat simply a prawn, because generally it is. In bygone days of Blighty potted brown shrimp caught on the tidal sands in places like Morcombe, the Severn Estuary and the North Norfolk Wash, were a delicacy loved by James Bond, and Queen Elizabeth II, but today they’re hardly ever seen on modern menus.

In fact, of total UK shrimp and prawn sales, less than 1.8% are shrimps, while 60.7% sales are from warmwater prawns, and 37.5% come from coldwater prawns.


When it comes to prawns there are in fact three varieties of note. The common prawn, the coldwater prawn, and various members of the warmwater prawn family. All share similar features, they’re decapods (ten legged), with two pairs of front legs with pincers and another three pairs of legs for crawling or swimming. They all have an armoury of unicorn like spears and spikes cresting from the middle of their forehead, which they use as a defence against predators.

The common prawn can be found on the cool but not necessarily cold British coastline, they have a thickish, transparent shell with stripy marks along their flank. The fishery here in the UK is exceptionally small, but on the odd occasion that prawns are landed they make for a glorious treat. Here in the South West, the common prawn is affectionately nicknamed by local fishermen as Billy Winters. Mainly this is because they’re landed often throughout the colder winter months – thus they became ‘Silly Billy Winters’.

Coldwater prawns, as the name implies, originate from the deep, cold, icy waters high up in the Northern Atlantic in places like Svalbard in Norway, Disko Bay in Greenland and the Arctic oceans where they grow slowly and develop their signature taste; a sweet and sea-salty flavour with a nice and juicy texture. These prawns are caught using otter trawls and are usually boiled and blast frozen out at sea.

When you buy a ‘pint of shell on prawns’ at any one of our restaurants it’s these you’ll get. We’ve specifically chosen coldwater prawns from the Marine Stewardship Council certified fisheries of Norway. This is a really well managed fishery, which as early as 1992 adopted stringent rules for prawn fishermen. Vessels are obliged to use gear with a minimum mesh size (35mm), as well as sorting grids to reduce the amount of bycatch. Being blast frozen at sea does wonders to retain their fresh flavour and texture making them an excellent example of prawn fishing done well. 

Warmwater prawns by comparison come in many shapes and sizes but tend to be much larger than the coldwater sort. They include tiger prawns as well as varieties like king prawns, jumbo prawns, and fantail prawns. These species grow in the tropical waters of places like, Thailand, Vietnam, Ecuador, India, and Bangladesh.


When it comes to fishing for wild prawns the problems are twofold. Compared say to a flabby great cod, or giant hake, a prawn – warmwater or cold – is a relatively small creature. Therefore, when fishing for prawns with a trawl - the most commonly used method of catching commercially - the mesh has to be exceptionally fine or else the prawn will simply pass straight through. This means bycatch, as basically anything bigger than a prawn is at risk. Which puts huge amounts of added pressure on some potentially already fragile and overfished species.

The next problem is that prawns are hermaphrodites. They’re born boys. Then after a huge physical transformation age about two years’ old, they change sex and become female. Which is fine, other than the fact that everyone wants to eat great big juicy prawns – tiny little shrimpy things just won’t do. The problem with that is if you eat all the female-breeding population you quite quickly achieve total population collapse!


The difficulties surrounding prawn fishing, and the lack of careful management of wild stocks – especially amongst warmwater species – led, in the 1970s, to the rise of prawn farming. Today over 50% of all the prawns sold worldwide are farmed, with latest data showing this figure continuing to rise. 

Seafood farmers in places like Thailand – the largest exporter of farmed prawns worldwide - argue that marine protein is better for the planet when compared with livestock farming, they also make the claim that more farmed prawns mean less pressure on wild prawn stocks.

But farmed prawns come with huge environmental cost. Prawn farms are positioned in tidal areas to minimise the cost of pumping water. These intertidal zones just so happen to be the perfect habitat for mangrove forests. Uniquely adapted to survive in salt water, mangroves sequester up to four times more carbon than rainforests. According to Global Mangrove Watch, about 35% of the world’s mangrove forests disappeared during the 1980s and 1990s, with clearance for prawn farming being a key contributing cause.

To build a prawn farm, mangroves are ripped up by their roots, the area where they have happily existed for thousands of years is then flooded and seeded with juvenile prawns. These prawns are then artificially fed on what’s called ‘trash fish’, basically wild fish with little commercial value that is left to rot and be turned into fishmeal. It’s estimated that up to 25% of Thailand’s total marine catch ends up as being turned into fishmeal. Using wild fish to feed farmed fish is a big issue, as it puts more pressure on wild stocks rather than less. Scientists have estimated that as a result the waters around Thailand are being overfished by 250%.

After two to three years of farming, the flooded waters become so polluted with prawn waste – and the toxic chemicals used to neutralise it and prevent fungal disease – that it becomes too toxic for prawn farming. Even when the water is drained, the remaining soil is so polluted that crops can’t be grown for years.

Meanwhile, because of the mangrove’s capacity to absorb carbon dioxide, their destruction has implicated prawn farming as being responsible for a huge carbon input. A 2017 study conducted by forestry researchers Cifor, calculated that the clearing of mangroves meant that one kilo of farmed shrimp had almost four times the emissions impact of a kilo of beef.


The issues faced by the prawn farming industry go beyond the environmental destruction. As with any gold rush, there are winners and there is corruption. Huge amount of research has gone into lifting the lid on the human rights violation linked with warmwater prawn production.

Each stage of the supply chain (catching, processing, farms, hatcheries and fishmeal production) depends on labour-intense manual activities that are frequently carried out by low-skilled migrant workers without effective regulation or oversight, generating significant human rights risks.

Due to a desire to keep costs as low as possible, major exporting companies subcontract to external pre-processing facilities. These facilities, referred to as ‘peeling sheds’, remove the heads, veins and hard shell of prawns and prepare it for secondary or value-added processing.

This pre-processing stage of production is the most labour-intensive and least regulated aspect of an otherwise sophisticated supply chain. The informal nature of it makes it particularly prone to poor working conditions, breaches of national and international labour standards, child and forced labour, exploitation, and abuse.

An investigation ran by the non-governmental organisation, the Environmental Justice Foundation, revealed human trafficking, exploitation, bonded and child labour, are widespread within the warmwater prawn industry. According to the 2018 Global Slavery Index, there is an estimated 1.2m modern slavery victims in Indonesia, 421,000 in Vietnam and 610,000 in Thailand – many of which are involved within warmwater prawn production.


Mangrove swamp destruction, chemical spills, trash fish, bycatch species collapse from fine mesh trawling, slavery, and human exploitation – none of these things are new news when it comes to the prawn industry. Multiple online campaigns, undercover scoops in national papers, and Channel Four documentaries have all sought over the years to warn us of our penchant for prawns.

Have any worked? Not one bit. Or not according to the data. In fact, national retail sales of prawns, and particularly warmwater prawns, have continued to rise year on year. And while some prawn exporters have sought to clean up their act with ethical labelling and organic or environmental accreditations, these only account for less than 10% of the world’s prawn producers.

How British retailers have responded to the increasing demand for prawns and their questionable ethical qualities have been varied. Some have promised to put prawns at the top of their agendas for “supply chain investigation”, while others have remained very quiet.

At Rockfish, we see it as quite simple. We’ve always sought to only provide the highest quality seafood, from vessels and fisheries that we know and trust. We only want to sell the most sustainable and the freshest, and best looked after. That’s it. Which is why we literally scoured the planet for a solution to this prawn shaped problem, and why we’re thrilled to have eventually set up a UK supply chain with the Austral Fishery and their exceptional Skull Island Prawns.

The Northern Prawn Fishery is often referred to as Australia’s last ‘wild frontier’. The fishery covers approximately 880,000 square km, with less than 12% of that area being fished. 

Certified ‘sustainable’ by the Marine Stewardship Council, Skull Island tiger prawns come from the world’s first certified sustainable tropical prawn fishery. They are caught from August to November each year and only caught during the night to ensure minimal impact on bycatch. Meanwhile, specialised nets are used to ensure turtle bycatch is non-existent.

The remainder of the year is closed to fishing to ensure juvenile tiger prawns have ample time to grow into adults and reproduce. 

Prawn stocks are maintained at healthy, sustainable levels with annual scientific sampling and surveys, as well as a multi-year scientific review of the status of the fishery.

Like everybody, we love prawns at Rockfish, but some we find hard to trust, their environmental and human impact is just not a price we’re willing to pay – not matter how cheap they are. But Skull Islands are certainly something different, a step in a new direction, towards a better future, a prawn everybody can love.