There are many different methods to harvest seafood, and the way in which we fish has changed dramatically over the centuries. Hand harvesting is the simplest method of fishing and is still used by subsistence communities.
Though very simple, hand harvesting is a highly selective way to collect seafood. Along our coastline, a number of species such as oysters, white mussels and seaweeds are commercially harvested in this way, by diving, by hand from rocky shores, or using simple hand-held tools.
Most modern commercial fishing methods now employ a great deal of technology and equipment. The major commercial fishing methods include: HOOK AND LINE, PURSE SEINE, TREKNET, TRAWL, LONGLINE & TRAPS
See below for more info
Hook and Line Fishing Methods
Traditional linefishing uses hand lines and fishing rods with baited hooks. Linefish are caught from commercial ski-boats and sometimes larger deck-boats. It is a fairly selective method. By using varying hook sizes, bait types and carefully selecting localities, species can be specifically targeted thereby reducing bycatch. The fish caught are also of very good quaity as they are individually handled. The biggest issue with linefishing is that many of our species are rare and in urgent need of recovery.
Examples of highly specialised and selective linefishing methods are:
Tuna pole fishing, targets tuna, such as yellowfin and longfin (albacore) with virtually no bycatch. Tuna are attracted to boats by spraying jets of water onto the surface of the sea. They are then caught on baited hooks on short lines attached to strong bamboo poles.
Squid jigging, targets local tjokka (chokker-) squid. Also widely known as Calamari, squid are attracted to boats at night by powerful lights and caught with barbed lures that are hauled vertically through the water.
Longlining
Longlining is the other major industrial fishing method and involves using a main line with hundreds of baited hooks. Longlines can be up to 100km long with as many as 20 000 baited hooks. Longlines may be set on the seabed (demersal), or near the surface (pelagic), depending on the target species.Species targeted include tunas, sharks and swordfish, hake, and Patagonian toothfish. The main issue with longlining is the bycatch of threatened seabirds, turtles, and billfish, though this maybe reduced through preventative measures.
Purse-seining
This involves the use of a large net to encircle shoaling fish. The net is drawn closed around the shoal like a bag. As purse seine vessels target small pelagic shoaling fish such as sardines and anchovies, and the gear is selective, bycatch of other species is normally low. The primary potential impact of catching these species is termed the ´ecosystem effect´.
Small pelagic fishes are ecologically important as prey for many marine predators (sharks, seals and seabirds)- therefore, if too much is caught it may affect the health of the entire ecosystem. Tuna purse seining is not practiced in South Africa but in some countries it results in the death of dolphins.
Pots, traps and hoop nets
Pots, traps and hoop nets are used to catch slower moving or bottom dwelling sea creatures such as rock lobsters, crabs, and octopus. Traps are baited and set on the seafloor for a period of time, before being retrieved. The method is generally very specific, though minor concerns are ghost fishing (when a trap is lost but carries on fishing), and occasional entanglement of whales in trap lines.
Trawling
Trawling, also known as dragging, is the most widely used industrial fishing method. It involves towing a large net across the seabed (bottom or demersal trawling) or through the water (mid-water trawling) to catch fish that live there. Hake, sole, and prawns are all species in South Africa targeted using bottom trawl gear.
Retained bycatch include other fish, sharks, squid, deep water crabs and lobster. The main issue with trawling is that it is non-selective, and depending on the target species may have a substantial bycatch. Prawn trawling is one of the fishing sectors with the highest discarded bycatch (over 70%), accounting for one third of the global discarded catches.Demersal trawling can also alter the seabed and may damage sensitive habitats such as deep-water coral reefs and seamounts.
Midwater trawling is more selective and does not damage the seabed. It mainly targets horse mackerel or maasbanker.
Beach seining
Beach seigning or treknetting is traditional fishing method where schools of fish are encircled from the shore with a long net dragged by a rowing boat, and hauled up onto the beach. This method is used to catch yellowtail and mullet in the Western Cape and sardines in KZN during the annual sardine run.
The method has a much more localised impact compared to industrialised fishing methods; however nets are by their nature non-selective. The Western Cape fishery in particular may have a significant bycatch of rare linefish such as white steenbras (which it formerly targeted) during their spawning migration. Fish may be released alive though, if the fishers comply with regulations.