Production Method Guide

This guide is intended for seafood vendors to determine the appropriate production method of their seafood products when completing the surveys sent to them by FishWise. It is also useful to anyone who wants to learn more about the various methods used to harvest seafood from wild fisheries and aquaculture operations.


Steps to determine the production method of your seafood products:

1. Determine if the product is WILD or FARMED

2. Determine the production category (in black box)

3. Read all production method descriptions to determine which of the bold, green methods best applies to your product

Bottom Trawl (Otter Trawl, Skimmer Trawl, Dragger, Danish Seine)

Bottom trawls are weighted, funnel-shaped nets that are dragged behind boats along the seafloor. Bottom trawls are used to catch bottom-dwelling species like flatfish and shrimp.

Midwater Trawl

Midwater trawls are funnel-shaped nets dragged behind boats in the middle of the water column. Pollock and hake are caught with midwater trawls.

Gillnet (Bottom Gillnet, Drift Gillnet, Tangle Net, Surface Net, Strike Net)

Gillnets are nets that are set in the water and designed to entangle fish. Fish will swim into the net and, if they are the right size, become stuck in the mesh, typically by their gills. Gillnets are one type of gear used to catch wild salmon.

Purse Seine: FAD

FAD (Fish Aggregating Device) purse seines employ the use of floating man-made objects designed to attract pelagic fish. The purse seines encircle the attracted school of fish and haul them to the surface. Tuna can be caught using FAD purse seines.

Purse Seine: FAD Free (Unassociated, Free School, Haul Seine)

Purse seines that do not employ Fish Aggregating Devices (FADs) are set on naturally forming schools of fish. The nets encircle a school, are drawn tight and the fish are hauled to the surface. Sardines and tuna can be caught using purse seine methods that are not associated with a FAD.

Hooks & Lines:
Longline (Pelagic Longline, see below for Bottom Longline) )

Longlines consist of a main line with a series of baited hooks, sometimes many miles long with thousands of hooks. The line is deployed at shallow to mid depths for variable amounts of time depending on the target species. Tuna, swordfish, and mahi mahi are often caught with longlines.

Bottom Longline (Setline, Trotline)

Bottom longlines are weighted longlines used to fish near or on the seafloor. Black cod and halibut can be caught with bottom longlines.

Handline (Pole, Troll, Hook and Line, Beam Troll, Rod and Reel, Jig, Gig)

Handline methods are designed for use in the hands of or under the immediate and continuous supervision of a fisherman. Many pelagic species like albacore are caught using handline methods.

Dredge (Bottom Dredge)

A dredge is a rigid metal gear that is dragged to rake the bottom for species such as scallops.

Trap (Pot, Cage, Trap Net, Pound Net, Hoop Net, Reefnet)

Traps and pots are enclosures that are generally baited and left on the seafloor to catch various species. Crabs, fish, and lobsters can be caught using this method.

Hand Methods (Hand Rakes, Diver Caught, Cast Net, Tongs, Scottish Seine, Beach/Hand Seine, Harpoon, Spear, Hoop Net, Conical Net)

Hand methods include all methods where a person collects species by hand. This can include diver caught shellfish or harpooned fish, like swordfish.

Raceways, Ponds & Recirculating Systems:

A raceway is a flow-through system to allow for aquaculture at inland locations. The flow can be man-made or the raceway could be placed in a flowing river or stream. Any water discharged is treated prior to release. Trout are typically farmed in raceways.

Ponds: Open Exchange (Frequent Exchange)

Open exchanging ponds can be located coastally and flushed with the tides, or located inland and flushed using fresh water. These systems exchange their water more frequently than twice per production cycle. Waste water is generally not treated before it is flushed into a natural water body. Shrimp are often farmed using this method.

Ponds: Infrequent Exchange (Harvest Exchange)

Infrequent exchange ponds are generally excavated inland and exchange their water less frequently than twice per production cycle. Alternatively, a system may be considered infrequent exchange if waste water is reused for irrigation and not allowed to re-enter an aquatic ecosystem except after filtration through substrate, or filtered to completely remove biotic organisms and abiotic nutrient enrichment before contact with aquatic ecosystems. Catfish, shrimp, tilapia, and freshwater prawns can be farmed using these pond systems.

Recirculating (Closed Containment, Zero-Exchange Systems)

These systems never discharge water to the surrounding environment and do not have direct contact with a natural body of fresh or marine water. They can be located virtually anywhere and reuse all of their water. Large tanks are often employed and advanced filtration techniques allow wastewater to be cleaned for reuse. These systems can utilize both fresh and salt water and can culture many species like shrimp, tilapia, barramundi, and salmon.

Net Pens & Open Systems:
Net Pen (Cage)

Net pens and cages are a way to farm fish in a water body using anchored or unanchored structures. Fish that are raised in net pens or cages in salt water, fresh water, and man-made reservoirs are fed and monitored by an aquaculture facility until harvest. Production can be inshore (e.g. salmon in coastal waters), offshore (e.g. grow-out pens for yellowtail and some tunas in deeper water tens of miles from shore) or in lakes and reservoirs (e.g. Arctic char and tilapia).

On Bottom Aquaculture (Seeded Seafloor, Sea Ranched)

On bottom aquaculture is typically associated with farmed shellfish in natural water bodies. On bottom farming involves seeding the seafloor with juveniles and then harvesting them once they have grown to the appropriate size. Clams and oysters can be farmed with this method.

Off Bottom Aquaculture (Ropes, Baskets, Mesh Bags, Trays)

Off bottom aquaculture is associated with farmed shellfish in natural or manmade water bodies. With off bottom aquaculture, shellfish are grown on ropes or in baskets, mesh bags, and stacked trays suspended above the seafloor and are harvested by hand. Oysters, scallops, and mussels can be farmed with this method.