Silver kob

1. What is it?

Silver kob (Argyrosomus inodorus) are fast growing, endemic fish species. The stock assessment was updated in 2017 and indicated the stock is overfished and undergoing overfishing. Current biomass levels are estimated at 10% of pristine levels indicating that the silver kob stock has collapsed. Silver kob are caught as bycatch in the inshore demersal trawl fishery for hake (MSC certified) and sole.

2. How was it caught or farmed?

Linefishing

Silver kob are caught using traditional linefishing methods. Linefishery operates from small ski- and deck boats using a rod and reel or handline making them a popular target for recreational line fishers. Linefishing is a relatively selective fishing method with few impacts on the marine environment and very little accidental bycatch.

Inshore demersal trawl

Silver kob are caught as bycatch using trawl nets that are dragged along the seabed at depths up to the 110 m isobath or 20 nautical miles from the coast. This type of trawling is known to damage the seabed; however the extent and impact of damage remains unknown. Trawling is not a very selective fishing method and a number of other species are often caught in the nets (fish, sharks and rays). Substantial effort has been made to reduce seabird deaths through the use of tori lines (bird-scaring lines) and work is underway to better understand impacts on endangered, threatened or protected species.

3. Where is it from?

Linefishing

Silver kob are captured within the inshore zone from the northern Namibia to southern Transkei. Management for the sector is considered partly effective. In South Africa this sector is principally managed through a total allowable effort (TAE) limitation and there are additional restrictions to protect overfished species such as bag (5pp/pd–for anglers west of Cape Agulhas and 1pp/pd – for anglers east of Cape Agulhas) and minimum size limits (> 50 cm) for recreational fishers. There is some concern over the impact of the small-scale fishery rights allocation beyond the recommended TAE and the continuously growing recreational sector.

Inshore demersal trawl

Silver kob are caught mainly on the Agulhas Bank off the South Coast. Management measures are considered to be largely effective and mainly focused on the target species (hake and sole) in the form of Total Allowable Catch (TAC) and permit limitations. Additional measures in place include precautionary catch limits and fishing only in historical fishing grounds. More effort is required to improve at-sea scientific observation of fishing activities to better understand ecosystem impacts.