Bycatch management

Trawling is an unselective fishing method and consequently the South African hake trawl fishery may be considered a multispecies fishery; although Cape hakes are the target species, approximately 20 other species are regularly caught in trawl nets.

Bycatch is considered to be a valuable part of the trawl catch and a number of bycatch species are important for food security. For instance, horse mackerel, snoek, ribbon fish, panga and angelfish are a good source of affordable animal protein for lower income groups, particularly in the Western Cape. Other bycatch species, most notably kingklip and monk, are highly prized on export markets.

In recent years, SADSTIA has worked with scientists and conservationists to institute measures aimed at better managing the bycatch component of the deep-sea trawl fishery.

In May 2016, SADSTIA announced a new three-year partnership with WWF that will improve the management of 12 by-catch species.

The effort limitation, or “sea days” regulation plays an integral role in curbing fishing strategies that result in excessive targeting or catching of bycatch species. Effort limitation caps fishing effort and eliminates opportunities to use excess effort to target bycatch species once quotas for hake have been exhausted.

Precautionary upper catch limits have been set for kingklip and monk.

The Bycatch Fishery Conservation Project

The three-year South African Offshore Trawl Bycatch Fishery Conservation Project is undertaking research and implementing practical actions with the goal of improving the environmental performance and sustainability of the fishing activity of SADSTIA’s members, with a particular focus on non-target species management.

The non-target species are kingklip (Genypterus capensis), monk (Lophius vomerinus), angelfish (Brama brama), Cape dory (Zeus capensis), gurnard (Chelidonichthys capensis), horse mackerel (Trachurus capensis), jacopever (Helicolenus dactylopterus), octopus (Octopus vulgaris), panga (Pterogymnus laniarus), ribbonfish (Lepidopus caudatus), snoek (Thyrsites atun) and a number of skate species.

Although these species are collectively referred to as “non target species” or “by-catch”, they are retained and processed by trawl operators and many of the lower value species, for example panga, snoek and angelfish, are valued as a source of good quality animal protein by lower income groups, particularly in the Western Cape.

In spite of their importance, the management of these species has traditionally taken a backseat to the Cape hakes (Merluccius paradoxus and M. capensis) that are the target of the deep-sea trawl fishery. The FCP seeks to improve knowledge about these non-target species and improve their management.

Some of the most common bycatch species of the deep-sea trawl fishery

Kingklip

Genypterus capensis
Other names: Ling or Cusk Eel (in Australia and New Zealand)

Although a kingklip resembles an eel, its body is not round in cross section. It is tinged with a light pink colour and covered in irregular brown blotches. Kingklip can grow to 150cm in length.

Kingklip has always formed part of the catch of both the deep-sea and inshore hake trawl fisheries. Until a precautionary upper catch limit of 3 500 tons per year was applied to kingklip, catches averaged about 4 500 tons per annum. Because kingklip mainly occur on rocky terrain that is difficult to trawl, only small volumes are caught throughout the year, except for a window period during late August, September and October. Certain trawl grounds are seasonally closed to protect spawning aggregations of kingklip.

The name “kingklip” comes from the old Dutch word “koningklipvisch” which translates as “king of the rock fishes”.

Snoek

Thyrsites atun
Other names: Cape snoek; Barracouta (New Zealand and Australia)

The snoek is an elongated, silvery fish that is widely distributed in southern Africa, from northern Angola to Port Elizabeth. However, most fish are found between the Cunene River and Cape Agulhas. The snoek is a medium-sized fish that reaches a maximum length of 2m, corresponding to a mass of 9kg. In South Africa, adult fish prey mainly on sardine, anchovy and mantis shrimps.

Snoek is caught in trawl nets with hake and is a common “by-catch” species of the South African deep-sea and inshore trawl fisheries. Snoek is also an important catch of the traditional linefishery, particularly in the western and southwestern Cape and the species is targeted by recreational linefishers, usually from ski-boats.

Monk

Lophius vomerinus
Other names: Monk fish, mock crayfish

Monk is endemic to southern Africa. It is a demersal (bottom dwelling) species that occurs in deep water, usually between 90 and 500m in depth. It has a large, flattened head with a huge mouth, spanning the full width of the head. This allows the fish to swallow prey (usually small fish) as large as itself.

Monk is a classical by-catch of the hake trawl fishery, especially on the west coast. Specific trawling techniques and an experienced crew are required to fish for monk, yet the hake component always remains the major portion of the catch. As such, monk has always been accepted as an important component of the hake trawling business, averaging about 4% of the total hake catch across the entire fleet. Today monk catches are controlled by a 7 000 ton precautionary upper catch limit.

Horse mackerel

Trachurus capensis
Other names: Maasbanker; Cape horse mackerel; Carapau (in Portugal)

Horse mackerel is a pelagic fish species, meaning the fish form large schools in the surface layers of the ocean – the pelagic zone. The fish is silver with green markings and similar in shape and appearance to other pelagic species, such as sardine and anchovy. Although the horse mackerel can grow to 50cm in length, most adult fish are between 25 and 30cm long.

Horse mackerel occurs along the entire coast of South Africa and Namibia, with the biggest concentrations found between the west coast and the Agulhas Bank. It is a common by-catch of the deep-sea trawl fishery and is mostly produced and packaged whole, in frozen form. There are markets in rural South Africa and other African countries where horse mackerel is a staple source of protein.

Buttersnoek

Lepidopus caudatus
Other names: Ribbonfish; Silver scabbardfish

Growing to a length of 2m, this is a slender, ribbon-like fish with a tapering body and a small forked fin. Because it is scaleless, the body of a buttersnoek is very bright silver. Buttersnoek occur on the west coast and Agulhas Bank, usually on sandy seabeds at depths of between 100 to 250m. A schooling species, buttersnoek feeds on crustaceans, small squid and fish.

Angelfish

Brama brama
Other names: Atlantic pomfret

Angelfish are a deep water species that should not be mistaken with the coral reef fishes of the same name that occur in tropical waters. They are disk shaped with forked tails and a blunt snout. Silver in colour, the Angelfish has distinctive gold eyes.

Jacopever

Helicolenus dactylopterus
Other names: Jacks, Blackbelly Rosefish (in the Northern hemisphere); Sea Perch (Japan and New Zealand)

The Jacopever is a red-orange fish with a white belly and chest. It is caught on soft seabeds at depths of between 50 and 500m. False Bay is an important breeding ground and large numbers of Jacopever are found off the southern and western Cape coast.

John Dory

Zeus faber
Other names: Target John Dory

John Dory are endemic to South Africa, occurring in deep water (140 to 400 m) on the west coast. The grey-green fish are very easy to identify because they are almost scaleless and have mournful looking faces. The prominent round blotches on their sides are very distinctive and explain the common name “Target John Dory” which is given to this fish in other parts of the world.