Seafood Harvest Methods

Beach seines consist of a long net operated from shorelines by hand. The net is weighted at the bottom and has floats at the top. Fishers use the beach seine to encircle fish which are then brought onto shore. Since schooling or spawning fish are easily targeted by beach seines, the use of beach seines must be well-regulated in order to be sustainably used.

Gillnets are walls of netting suspended in the water column. Gillnets are invisible to the fish who attempt to pass through and become entangled by their gills. Gillnets are generally a selective way of fishing when used in salmon fisheries, but can cause bycatch when used to target warmwater species such as blue swimmer crabs.

Bottom longlines are structurally similar to pelagic longlines with a central fishing line strung with hundreds of lines with baited hooks, except they are weighed down to fish close to the ocean floor. By using specific hooks and sinking the lines deeper, the amount of bycatch can be significantly reduced.

A bottom trawl consists of a large, weighted net dragged behind a moving fishing vessel. This is a generally unselective way of fishing and can cause large amounts of bycatch. When used over certain types of bottom habitat, the trawls can cause the destruction of physical structures such as corals, sea sponges, etc. and cause the injury or mortality of organisms. Impacts of bottom trawls can be minimized by modifying the nets and implementing management measures that limit the areas trawled. Species typically targeted: Groundfish such as cod, halibut, sole, and rockfish.

Like greenstick gear, buoy gear was also developed to reduce bycatch levels. This fishing gear targets swordfish. Buoy gear consists of several buoys from which one to two baited hooks are attached. Each buoy is equipped with a light, and the buoys are connected with a main line in a straight configuration. The gear is deployed at dusk. When a swordfish is hooked, it drags the buoy out of line which is visibly detected using the lights, and can be reeled in.

Casitas mean “little house”. They are a passive fishing technique and consist of  constructed structures set on the ocean floor. Lobsters are drawn to the casitas where they seek shelter. They are free to come and go from the casitas. Fishers dive down to harvest lobsters from the casitas.

Cast nets are small nets weighted at the edges. The cast net is thrown into the water from shore, and the weights cause the net to sink around a school of fish. The fish are then hauled in.

Traps and pots are baited, immobile enclosures placed on the ocean floor and typically target crustaceans, however they can also target bottom dwelling fish such as cod or sablefish. The animals are able to enter the trap/pot through an opening of a specific size and shape, but are unable to leave. Traps and pots are selective as they are designed to catch specific species. The mesh size on the traps allow for undersized or immature individuals to escape. Additionally, any bycatch accidentally caught e.g. non-target species like octopus, undersized individuals, and females carrying eggs can be released live and uninjured. Traps and pots are generally a sustainable way of fishing, unless they are placed in areas where the main fishing line which ties them together has the potential to entangle migrating marine mammals, or if they are placed on top of sensitive habitat.

A bottom trawl or Danish seine, consists of a large, weighted net dragged behind a moving fishing vessel. This is a generally unselective way of fishing and can cause large amounts of bycatch. When used over certain types of bottom habitat, the trawls can cause the destruction of physical structures such as corals, sea sponges, etc. and cause the injury or mortality of organisms. Impacts of bottom trawls can be minimized by modifying the nets and implementing management measures that limit the areas trawled. Species typically targeted: Groundfish such as cod, halibut, sole, and rockfish.

Deepset longlines are structurally similar to pelagic longlines with a central fishing line strung with hundreds of lines with baited hooks, except they are weighed down to fish close to the ocean floor. By using specific hooks and sinking the lines deeper, the amount of bycatch can be significantly reduced.

A bottom trawl consists of a large, weighted net dragged behind a moving fishing vessel. This is a generally unselective way of fishing and can cause large amounts of bycatch. When used over certain types of bottom habitat, the trawls can cause the destruction of physical structures such as corals, sea sponges, etc. and cause the injury or mortality of organisms. Impacts of bottom trawls can be minimized by modifying the nets and implementing management measures that limit the areas trawled.

Divers use SCUBA gear to hand harvest species found on the ocean floor. They typically target species such as sea urchins and scallops. Diver-caught seafood is a selective way of fishing because divers visually identify the seafood before harvesting, so bycatch levels are negligible. Divers do not typically cause habitat damage.

Dredges consisting of large metal baskets are dragged over the ocean floor behind a moving vessel. Large metal teeth dig into the ocean floor to lift up clams or shellfish buried in the sand which can cause significant habitat damage and bycatch. Limiting the area in which dredges are used and targeting sandy, rather than hard bottoms can help to minimize their impact.

Species typically targeted: shellfish e.g. scallops, oysters

Gillnets are walls of netting suspended in the water column. Gillnets are invisible to the fish who attempt to pass through and become entangled by their gills. Gillnets are generally a selective way of fishing when used in salmon fisheries, but can cause bycatch when used to target warmwater species such as blue swimmer crabs.

Purse seines are nets that are deployed around a school of fish to encircle them. The netting is then pulled shut much like “purse strings” and can be hauled up onto the boat. Depending on the species targeted, purse seines can cause varying amounts of bycatch. Purse seines are often used with a fish aggregating device (FAD). An FAD consists of floating material which attracts open-ocean fish which congregate beneath the FAD. Purse seines can then encircle the schools of fish around the FAD. This method is commonly used in tuna fisheries and can catch many threatened species as bycatch such as sharks, juvenile tunas, turtles, etc. Purse seines are highly selective when used to catch school of salmon.

Raceways consist of water running through a channel where the fish are contained. The water is often diverted from a natural water body. If untreated, wastewater can contaminate waterways and spread disease, but  this risk can be eliminated if the water is treated before being discharged. Unless there are prevention measures in place, there can also be a risk of farmed fish escaping and impacting wild populations.

Gillnets are walls of netting suspended in the water column. Gillnets are invisible to the fish who attempt to pass through and become entangled by their gills. Gillnets are generally a selective way of fishing when used in salmon fisheries, but can cause bycatch when used to target warmwater species such as blue swimmer crabs.

Greenstick gear was developed as a fishing technique that would reduce the high bycatch levels of tuna fisheries. With this fishing method, a moving vessel is equipped with a vertical pole (the “greenstick”) from which a main fishing line is deployed and kept straight using a float at its end. Up to 10 artificial lures are attached to the main line with individual lines and skip across the water in order to attract tunas. When a tuna is hooked, the individual line detaches from the main line and can be reeled in.

Hand harvesting refers to the manual extraction of seafood species. Hand harvesting is a selective method of fishing/farming as humans visually identify the seafood species before harvest. This avoids the extraction of non-targeted species, and minimizes habitat damage.

Hand harvesting refers to the manual extraction of seafood species. Hand harvesting is a selective method of fishing/farming as humans visually identify the seafood species before harvest. This avoids the extraction of non-targeted species, and minimizes habitat damage.

Hook and line fishing is a highly selective way of fishing. A fishing vessel pulls several fishing lines with flashing lures through the water column. This method is selective because only fast-moving fish can swim quickly enough to take the bait, and any non-target fish which is accidentally caught can be immediately returned to the ocean live. This fishing method does not make contact with the ocean floor and causes minimal amounts of habitat damage.

Harpoons target one individual at a time, making it a highly selective way of fishing. Fishermen identify the species of fish and size before harpooning it.

Dredges consisting of large metal baskets are dragged over the ocean floor behind a moving vessel. Large metal teeth dig into the ocean floor to lift up clams or shellfish buried in the sand which can cause significant habitat damage and bycatch. Limiting the area in which dredges are used and targeting sandy, rather than hard bottoms can help to minimize their impact.

Jigs are a fishing technique normally used to catch squid. Fishing vessels illuminate the water which attracts the squid or fish, and baited hooks are mechanically jerked in the water to simulate the movement of prey. Jigging is a sustainable fishing method as it does not damage the habitat, and causes very little bycatch.

Gillnets are walls of netting suspended in the water column. Gillnets are invisible to the fish who attempt to pass through and become entangled by their gills. Gillnets are generally a selective way of fishing when used in salmon fisheries, but can cause bycatch when used to target warmwater species such as blue swimmer crabs.

Pelagic longlines are a non-mobile way of targeting open-ocean fish. A fishing line up to 150 km long is floated at the surface of the water from which thousands of baited hooks are suspended for hours to a few days. While pelagic longlines cause little habitat damage, they are an unselective type of fishing and can cause high levels of bycatch. Non-target species caught by pelagic longlines can consist of juvenile individuals who have not yet reproduced, or threatened species such as albatrosses, sharks, and sea turtles.

Bottom longlines are structurally similar to pelagic longlines with a central fishing line strung with hundreds of lines with baited hooks, except they are weighed down to fish close to the ocean floor. By using specific hooks and sinking the lines deeper, the amount of bycatch can be significantly reduced.

Gillnets are walls of netting suspended in the water column. Gillnets are invisible to the fish who attempt to pass through and become entangled by their gills. Gillnets are generally a selective way of fishing when used in salmon fisheries, but can cause bycatch when used to target warmwater species such as blue swimmer crabs.

Mid-water trawls operate in a similar way to bottom trawls, except they are dragged through the middle of the water column, and are not weighed down to drag over the ocean floor. This minimizes habitat damage. Mid-water trawls still have the potential to cause high levels of bycatch such as sea turtles.

Off-bottom farming is typically used to farm shellfish such as mussels, oysters, clams, and scallops. Floating rafts, bags, or suspended ropes are used to grow the shellfish. This system makes no contact with the seafloor, and the shellfish are harvested with little to no bycatch. Since shellfish are filter feeders, they offer ecosystem benefits by reducing nutrient load in the water. They also do not require any external feed as they extract nutrition from plankton in the seawater. This means that shellfish farming puts no pressure on wild fish stocks for feed.

On-bottom culture is a method of farming shellfish on the beach. Shellfish are typically transferred from hatcheries and seeded onto the beach where they continue their grow-out. On-bottom culture is usually a sustainable way of farming.

Open net pens can be problematic because the farmed species are in direct contact with the ocean ecosystem. Waste water can affect the benthic habitat directly below the farms, and there is the risk that if farmed fish develop diseases and parasites, these can be passed on to wild populations. If any farmed fish escape from the pen, they can negatively affect wild populations by competing with them for food and habitat. Hybridization with wild individuals is also a concern, since this could produce genetically less fit offspring and compromise the quality of the wild population. If antibiotics are used in the net pens, their open nature and direct contact with the environment makes the potential for spread of antibiotic resistance in humans a serious concern.

Pelagic longlines are a non-mobile way of targeting open-ocean fish. A fishing line up to 150 km long is floated at the surface of the water from which thousands of baited hooks are suspended for hours to a few days. While pelagic longlines cause little habitat damage, they are an unselective type of fishing and can cause high levels of bycatch. Non-target species caught by pelagic longlines can consist of juvenile individuals who have not yet reproduced, or threatened species such as albatrosses, sharks, and sea turtles.

Mid-water/pelagic trawls operate in a similar way to bottom trawls, except they are dragged through the middle of the water column, and are not weighed down to drag over the ocean floor. This minimizes habitat damage. Mid-water trawls still have the potential to cause high levels of bycatch such as sea turtles.

Hook and line fishing is a highly selective way of fishing. A fishing vessel pulls several fishing lines with flashing lures through the water column. This method is selective because only fast-moving fish can swim quickly enough to take the bait, and any non-target fish which is accidentally caught can be immediately returned to the ocean live. This fishing method does not make contact with the ocean floor and causes minimal amounts of habitat damage.

Shrimp or other fish farmed in ponds in Asia can be unsustainable when sensitive mangrove forests are destroyed in order to make space for the ponds. These mangrove forests are critical to the functioning of the ecosystem as they serve as important fish nurseries where juvenile fish can take cover from predators. Deforestation of mangrove forests affects fish populations in the ocean. Management can also be unenforced, leading to the use of illegal or uncontrolled use of chemicals such as certain antibiotics, fungicides and pesticides in the ponds. Ponds can be sustainable if they are located in areas that are not ecologically sensitive, if the water is treated before discharge or recirculated, and if there are adequate management measures and enforcement in place.

Traps and pots are baited, immobile enclosures placed on the ocean floor and typically target crustaceans, however they can also target bottom dwelling fish such as cod or sablefish. The animals are able to enter the trap/pot through an opening of a specific size and shape, but are unable to leave. Traps and pots are selective as they are designed to catch specific species. The mesh size on the traps allow for undersized or immature individuals to escape. Additionally, any bycatch accidentally caught e.g. non-target species like octopus, undersized individuals, and females carrying eggs can be released live and uninjured. Traps and pots are generally a sustainable way of fishing, unless they are placed in areas where the main fishing line which ties them together has the potential to entangle migrating marine mammals, or if they are placed on top of sensitive habitat.

Trap nets are a passive fishing technique. They are constructed out of stone walls or netting strung between wooden stakes to create a funnel that fish swim into. The fish remain entrapped and swim around inside the trap before the fishers scoop them out.

Purse seines are nets that are deployed around a school of fish to encircle them. The netting is then pulled shut much like “purse strings” and can be hauled up onto the boat. Depending on the species targeted, purse seines can cause varying amounts of bycatch. Purse seines are often used with a fish aggregating device (FAD). An FAD consists of floating material which attracts open-ocean fish which congregate beneath the FAD. Purse seines can then encircle the schools of fish around the FAD. This method is commonly used in tuna fisheries and can catch many threatened species as bycatch such as sharks, juvenile tunas, turtles, etc. Purse seines are highly selective when used to catch school of salmon.

Raceways consist of water running through a channel where the fish are contained. The water is often diverted from a natural water body. If untreated, wastewater can contaminate waterways and spread disease, but  this risk can be eliminated if the water is treated before being discharged. Unless there are prevention measures in place, there can also be a risk of farmed fish escaping and impacting wild populations.

Land-based tanks avoid many of the environmental risks associated with open net pens. The use of filtration systems to remove solid and particulate waste allows for the water to be reused and recirculated throughout the farm. Escapes are almost impossible as fish are on land in tanks and any disease or parasite outbreak is contained and won’t risk impacting wild populations.

Land-based tanks avoid many of the environmental risks associated with open net pens. The use of filtration systems to remove solid and particulate waste allows for the water to be reused and recirculated throughout the farm. Escapes are almost impossible as fish are on land in tanks and any disease or parasite outbreak is contained and won’t risk impacting wild populations.

Purse seines are nets that are deployed around a school of fish to encircle them. The netting is then pulled shut much like “purse strings” and can be hauled up onto the boat. Depending on the species targeted, purse seines can cause varying amounts of bycatch. Purse seines are often used with a fish aggregating device (FAD). An FAD consists of floating material which attracts open-ocean fish which congregate beneath the FAD. Purse seines can then encircle the schools of fish around the FAD. This method is commonly used in tuna fisheries and can catch many threatened species as bycatch such as sharks, juvenile tunas, turtles, etc. Purse seines are highly selective when used to catch school of salmon.

Pelagic longlines are a non-mobile way of targeting open-ocean fish. A fishing line up to 150 km long is floated at the surface of the water from which thousands of baited hooks are suspended for hours to a few days. While pelagic longlines cause little habitat damage, they are an unselective type of fishing and can cause high levels of bycatch. Non-target species caught by pelagic longlines can consist of juvenile individuals who have not yet reproduced, or threatened species such as albatrosses, sharks, and sea turtles.

Pelagic longlines are a non-mobile way of targeting open-ocean fish. A fishing line up to 150 km long is floated at the surface of the water from which thousands of baited hooks are suspended for hours to a few days. While pelagic longlines cause little habitat damage, they are an unselective type of fishing and can cause high levels of bycatch. Non-target species caught by pelagic longlines can consist of juvenile individuals who have not yet reproduced, or threatened species such as albatrosses, sharks, and sea turtles.

Silvofisheries are a sustainable alternative to traditional shrimp ponds. Shrimp are raised within the mangrove forest, and farmers are often required to maintain a certain minimum cover of mangroves. No external feed is given to the shrimp, as they feed off the natural forest resources. Chemicals are not used, and disease is controlled by not overcrowding the shrimp.

Mid-water trawls operate in a similar way to bottom trawls, except they are dragged through the middle of the water column, and are not weighed down to drag over the ocean floor. This minimizes habitat damage. Mid-water trawls still have the potential to cause high levels of bycatch such as sea turtles.

Harpoons or spears target one individual at a time, making it a highly selective way of fishing. Fishermen identify the species of fish and size before harpooning/spearing it.

Traps and pots are baited, immobile enclosures placed on the ocean floor and typically target crustaceans, however they can also target bottom dwelling fish such as cod or sablefish. The animals are able to enter the trap/pot through an opening of a specific size and shape, but are unable to leave. Traps and pots are selective as they are designed to catch specific species. The mesh size on the traps allow for undersized or immature individuals to escape. Additionally, any bycatch accidentally caught e.g. non-target species like octopus, undersized individuals, and females carrying eggs can be released live and uninjured. Traps and pots are generally a sustainable way of fishing, unless they are placed in areas where the main fishing line which ties them together has the potential to entangle migrating marine mammals, or if they are placed on top of sensitive habitat.

Trap nets are a passive fishing technique. They are constructed out of stone walls or netting strung between wooden stakes to create a funnel that fish swim into. The fish remain entrapped and swim around inside the trap before the fishers scoop them out.

Mid-water trawls operate in a similar way to bottom trawls, except they are dragged through the middle of the water column, and are not weighed down to drag over the ocean floor. This minimizes habitat damage. Mid-water trawls still have the potential to cause high levels of bycatch such as sea turtles.

A bottom trawl consists of a large, weighted net dragged behind a moving fishing vessel. This is a generally unselective way of fishing and can cause large amounts of bycatch. When used over certain types of bottom habitat, the trawls can cause the destruction of physical structures such as corals, sea sponges, etc. and cause the injury or mortality of organisms. Impacts of bottom trawls can be minimized by modifying the nets and implementing management measures that limit the areas trawled.

Hook and line fishing is a highly selective way of fishing. A fishing vessel pulls several fishing lines with flashing lures through the water column. This method is selective because only fast-moving fish can swim quickly enough to take the bait, and any non-target fish which is accidentally caught can be immediately returned to the ocean live. This fishing method does not make contact with the ocean floor and causes minimal amounts of habitat damage.

Purse seines are nets that are deployed around a school of fish to encircle them. The netting is then pulled shut much like “purse strings” and can be hauled up onto the boat. Depending on the species targeted, purse seines can cause varying amounts of bycatch. Purse seines are often used with a fish aggregating device (FAD). An FAD consists of floating material which attracts open-ocean fish which congregate beneath the FAD. Purse seines can then encircle the schools of fish around the FAD. This method is commonly used in tuna fisheries and can catch many threatened species as bycatch such as sharks, juvenile tunas, turtles, etc. Purse seines are highly selective when used to catch school of salmon.

Trap nets are a passive fishing technique. They are constructed out of stone walls or netting strung between wooden stakes to create a funnel that fish swim into. The fish remain entrapped and swim around inside the trap before the fishers scoop them out.