Mackerel, Cape horse
Scientific name
Trachurus capensis
Other names
Cape horse mackerel, Maasbanker, Carapau (Portuguese)
Fishing method
Midwater trawl
Area of capture
South Africa - FAO Area 47
SASSI colour
Green (CURRENTLY UNDER REVISION)*
Summary
Cape Horse Mackerel (Trachurus capensis) is a pelagic species, usually found up to a depth of 300m. They are mostly found over the continental shelf, often over sandy bottoms. The shoals rise to feed in surface waters at night but can be found close to the bottom during the day. Horse Mackerel are very abundant in South African and Namibian waters, though much of the catch is exported. The stock status of Cape Horse Mackerel is uncertain but expert opinion is that the stock is most likely under-fished.
Cape horse mackerel is targeted by midwater trawl. Vessels use large nets to drag the fish up to the vessel. Midwater trawl gear has a minimum mesh size 75 mm when stretched to its maximum. Trawling of fish takes place in the water column and the net is dragged between the bed and the surface of the sea without touching the bottom. The gear used in this fishery is not configured to come into contact with the bottom environment and thus this fishing method is not destructive to benthic habitat or species. Additionally, there is infrequent bottom contact. Because midwater trawls target very large schools of fish, bycatch forms a relatively small percentage of total catch by weight. However, numbers of individuals may be significant for some vulnerable species such as sharks, sunfish and seals. This is an unselective fishery and the survival level is unknown (the survival is thought by experts to be low as these animals mostly come onto deck dead). Common dolphins are impacted by the midwater trawl fishery. Horse mackerel managed in terms of a Maximum Precautionary Catch Limit (MPCL). The MPCL has been maintained at 44 000 tonnes in recent years and accommodates both mid-water-directed and bycatch in the hake-directed demersal trawl sector. Juvenile horse mackerel are occasionally targeted on the West Coast where a 5 000 tonnes precautionary catch limit is enforced (the whole small pelagic sector is closed if the limit is exceeded). Despite the absence of direct evidence of ecosystem change, there is potential for ecosystem impact as this is an important small pelagic species, and fills a similar ecosystem niche to other small pelagic species such as sardine and anchovy.
* Please note, Cape Horse Mackerel is currently under revision in terms of its WWF-SASSI sustainability rating, and more recent information incorporated into the assessment may affect its colour categorisation.
For more information, email us at sassi@wwf.org.za.