Responsible eating is only going to become more important, but how can we find our way when it comes to seafood? Fish and shellfish can contribute to a healthy, diverse diet, but there are some highly damaging fishing practices and species targeting to avoid. Somehow we need to balance enjoying delicious, nutritious seafood with respecting and caring for our seas. Thankfully Cornwall’s fishing community has long been ahead of the curve, and in some areas their management of our waters are a model of how sustainable fishing can be a great success for nature and community alike.
Here at Fish For Thought we have stood for truly sustainable seafood since our inception 15 years ago and champion this better way of doing seafood. There are many species that we simply refuse to sell, such as ray wings and dredged scallops, as doing so has too great an impact on our fragile ecosystems and vulnerable fish populations. We work closely with the Wildlife Trust’s Cornwall Good Seafood Guide (CGSG) and the Marine Conservation Society’s guidelines to use science to shape our policies on every species we sell. This is in contrast to many retailers who sometimes lean on meaningless blanket marketing clichés that ultimately harm our seas by providing a smokescreen for bad practices to hide behind.
Understanding the different ways that seafood is caught is crucial if we are to build a sustainable fishing future that also protects our stunning marine environments.
We’ve made it part of our mission to lift the curtain and educate the public on the different fishing techniques used by both the boats we work with, and the boats we don’t. If all consumers can become familiar with the impact of different types of vessels, they can start asking informed questions and make informed decisions on what seafood they choose to eat.
This is not an exhaustive list of all fishing techniques globally, but the ones most likely to have been used to catch fish you’ll find for sale here in the UK.
DEMERSAL/OTTER TRAWLING
This ‘lighter’ touch method of trawling is a lower impact fishing method compared to beam trawling. The nets are swept at the surface of the sea floor, as opposed to being physically dragged along it, and are typically made of nylon as opposed to heavy duty steel chain links. Instead of having a large metal beam holding the mouth of the net open, steel ‘doors’ at either end of the net mouth do the same job by hydroplaning once the boat is underway. A ‘foot rope’ that runs across the bottom of the net mouth runs along the sea bed, sending the fish up into the net itself. Mesh sizes are set large to reduce unwanted bycatch of juvenile fish. The majority of Cornish demersal trawlers use a mesh size (i.e. the size of the holes in the net) of 110mm, which is larger than the legally minimum required size of 100mm. This allows smaller juvenile fish to escape, mature and have a better chance of breeding.
With lighter nylon nets instead of metal chains, and no heavy metal beams to drag, these fishing rigs make it possible for the boats to be smaller, and use less fuel than beam trawlers. They typically go out at sea for a few days at a time.
Target species: Plaice - Lemon Sole - Dover Sole - Turbot - Brill - Haddock - Gurnard - Monkfish - Red Mullet - Cod - Ling - Coley
BEAM TRAWLING
This is among the most well-known types of fishing technique, and its reputation is not a positive one with fair reason. It is a high impact, indiscriminate method of fishing that significantly affects the biodiversity and habitat of the sea bed. As it is difficult to catch specific species without inadvertently capturing others, beam trawling is prone to by-catch of rare, slow-breeding species such as shark and ray from the benthic (sea bed) habitat.
The largest boats are 25-40 metres long, and each operates two trawl nets typically 12 metres wide each. These nets are made of heavy duty steel chain links and are dragged along the sea bed, designed to disturb any species present and so allow them to be scooped up by the net. A steel beam holds the mouth of the net open, so it is not reliant on the speed of the boat to open up the net. These large boats, often 1,000 horsepower, have a high carbon footprint due to the need for fuel to haul all that weight. Efforts are being made by the industry to reduce the impact of this method, such as ‘roller ball’ footropes that reduce damage to the seabed while reducing vessel fuel consumption.
These large, industrial scale boats can stay out at sea for 6-8 days, and are largely unaffected by bad weather so can constantly fish in that time.
Target species: - Plaice - Lemon Sole - Dover Sole - Turbot - Brill - Monkfish - Cod - Haddock - Pollack - Coley - Gurnard - Skate/Ray
GILL NETTING
This type of fishing does not trawl the water to capture the fish, but instead uses a stationary net that sits vertically up on the sea bed (looking a bit like an underwater tennis net) and passively catches passing fish. It is typically made of nylon, and is anchored at each end and along the base of the net with a weighted ‘foot rope’, while a series of floats along the top (the ‘head line’) create the vertical lift to the net.
The nets work by snagging the gills of fish that correlate to the mesh size. They stick their heads through the holes and can’t go further - any bigger they bounce off, any smaller and they slip through. This type of fishing is a more sustainable option as it does not damage the sea bed because there is no trawling involved. It is also designed to be selective as the size of the mesh will only catch certain species, minimising by-catch, while juvenile fish can pass through the net unharmed.
This type of fishing method cannot be used during strong tidal flows as the force of the water pushes the nets flat - this means that gill netter fishermen around Cornwall won’t go out in spring tides, or in very strong storms, of which there are a fair few around the Cornish coast in winter! The size of mesh and the length of time it is set in the water is dictated by the target species, and this is governed by legislation for each fishery. Each gill net can be up to 114 metres long and up to 30 nets can be linked together to make a singer ‘tier’. Large netting boats will deploy 5 or 6 tiers of nets per day, which can be almost 20km of nets.
As these boats are not trawling, they don’t require huge engines or large volumes of fuel. This gives gill netters a much lower carbon footprint compared to trawl fishing methods.
Target Species: Hake - Haddock - Pollack - Red Mullet - Gurnard
There are a few different types of gill nets used in Cornwall, that have different target species. Tangle nets are large mesh nets (20”), set slack on the seabed to entangle species such as monkfish, turbot, crawfish, Pollack and spider crab. Hake nets are set in deep water to target hake. They are 120-125mm mesh and stand 3 metres high off the seabed. Red mullet nets are small mesh nets, 70 – 90cm wide, set close to shore to target high value red mullet. Wreck nets are large mesh nets deployed over reefs and wrecks to catch pollack, saithe, ling and Cod.
CRAB AND LOBSTER POTS
Crab and lobster potting goes back centuries in Cornwall, and is still a significant economic activity around the coast, providing an important income for local skilled fishermen. It is a highly selective method of fishing that does not damage the sea bed and has no by-catch as fishermen can release any non-target species. They are mainly used to catch crabs, lobster and crawfish, but some specially designed alternatives are sometimes used for prawns, velvet crabs and cuttlefish. There are many different designs but the basic premise is that the pots are baited with something such as fish trimmings to entice crustaceans in, and then the interior structure of the pots is such that they are unable to escape. Traditionally they were made from willow withies but are now made from steel frames with nylon nets and plastic fittings. They are strung together into a ‘tier’ and dropped to the sea floor and either left for a set number of hours or days depending on the conditions and the environment. The fisherman then returns and hauls the lines of pots up using hydraulic equipment, removing any shellfish by hand as the pots are landed on the boat. A tier of pots can now be up to 100 long and fishermen often have several on the go so that while one line is being lifted, others are baited and actively catching. This is a very sustainable method of fishing. Because each pot is being examined by hand, the fishermen can return juvenile or egg-carrying breeding females back to the water alive, having had a good feed on the bait! The fishermen also carry out ‘V-notching’ on breeding female lobsters, whereby they clip a small v shape in the tail of the animal (a painless procedure) so that other fishermen know to return her too. This helps maintain a healthy population of lobsters in Cornish waters. There has also been an amazing discovery recently, that when flashing lights are placed in the lobster pot, it attracts scallops. This could be a whole new target species for potting, and one far, far less damaging to the sea bed than dredging, yet more efficient and scalable than hand-diving.
SCALLOP DREDGING
This is probably the most damaging form of fishing that takes place around our coastline. But to understand the fishing gear, first you need to understand the biology of the animal itself. Scallops are filter feeding animals, living on the sea bed in sandy or fine gravelly environments that allow them to wriggle flat down just at the surface. From this position they extend their fine tentacles from around the edge of their shell and filter plankton and other small organisms from the water. As scallops live just below the sea bed surface, any passing dredges, even those running along the sea bed will not be able to get at them. For this reason you need the most damaging aspect of scallop dredging - the teeth.
So back to the fishing gear. Scallop dredges are heavy-duty metal framed nets approximately 85 cm wide, which are pulled over the seabed. Those metal teeth are 10 cm in length and are mounted on the front of the dredge. They are there to dig into the seabed and flip the scallops out of the sand and into the nets. Dredges are mounted on metal bars, and a typical Cornish scallop dredging boat will pull a bar from each side of the vessel. Each bar will have up to 6 dredges mounted on it.
This action has a massive impact on sea bed biodiversity. Delicate sea fans, soft corals and sponges don’t stand a chance, and as they are slow-growing species, once razed they have little chance of growing back, especially as many areas are repeatedly dredged.
There is hope though - there has been an amazing discovery recently, that when flashing lights are placed in lobster pots, it attracts scallops to swim directly into the pots themselves. This could be a whole new method of catching scallops in a sustainable way - far less damaging to the sea bed than dredging, yet more efficient and scalable than hand-diving.
We never sell dredged scallops.
SCALLOP DIVING
The most sustainable method of harvesting scallops. This is when a diver goes down to the sea bed and collects scallops by hand, placing them in a net bag and returning to the surface. This hand-harvesting approach creates no damage to the sea bed, and responsible divers won’t harvest all the scallops in a given area, thus ensuring the local ecological balance is maintained and that breeding is not affected by hyper-local reductions in the population.
Scallops are filter feeding animals, living on the sea bed in sandy or fine gravelly environments that allow them to wriggle flat down just at the surface. From this position they extend their fine tentacles from around the edge of their shell and filter plankton and other small organisms from the water. It takes a skilled diver to spot them!
There has been an amazing discovery recently, that when flashing lights are placed in lobster pots, it attracts scallops to swim directly into the pots themselves. This could be a whole new method of catching scallops in a sustainable way - far less damaging to the sea bed than dredging, yet more efficient, less dangerous and more scalable than hand-diving.
HOOK AND LINE FISHING
Hook and line fishing (AKA handlining or jigging) is a very low impact, sustainable and indeed traditional method of catching fish. The method utilises a long line dropped straight into the water column, with hooks attached along the length of it and a heavy weight at the bottom. These hooks are equipped with lures designed to attract the target species, eg ‘feathers’ in the case of mackerel. Basically they mimic the prey of the fish, the fish bites the lure and is hooked then hauled aboard by the fisherman. When a shoal of fish is hit, the fish are shaken or knocked off the hooks into the boat as the line is pulled past a series of metal ‘strippers’.
The method is highly selective since it only takes out a small percentage of the shoal, and only works when the fish are feeding and not when they are breeding. The sea bed is left unharmed as there is no trawling or dredging involved and by-catch of any unwanted fish species is rare, and these can easily be returned to the sea unharmed if it does occur. As each fish is handled by an individual person (unlike industrial scale fishing), any undersized specimens can easily be returned to the sea unharmed, allowing stocks to be replenished by natural breeding cycles.
As it is typically carried out by small ‘day boats’ which work close to shore and rarely go out overnight, the scale of the catch is limited to how far and for how long they can fish for. Some vessels have invested in automated jigging machines called a ‘gurdy’ that can work several lines simultaneously but these are still low-impact compared to industrial fishing methods like beam trawling.
Target species: mackerel, sea bass, pollack, ling
With thanks to the Cornwall Good Seafood Guide for their support on providing up to date information.
