Thyrsites Atun
Colour, Shape and Size
The general body colour of this elongate, somewhat compressed fish is predominantly silver. The forsal surface is grey blue and the underside is white. The fins are dusky to black but the prominent dorsal spines are much lighter. The lateral line is conspicuous and wavy. Attains 150cm.
External Anatomy
The body is covered with numerous minute scales arranged in series along the well-defined lateral line. The single dorsal fin consists of 18-19 long, stout spines followed by 10-12 rays plus five or six finlets, while the anal fin has three
spines followed by 8-11 rays plus five to six finlets. The large caudal fin is forked and the small pelvic fins are situated far forward on the body, just
below the pectoral fins. Sharp triangular teeth arm the large mouth. The
first gill arch has 20-25 small paired rakers.
Natural History
This fierce shoaling predator undertakes extensive migrations along the West Coast each year. Though generally found in coastal waters it also occurs off shore, where considerable catches are made by trawlers. Despite its size and formidably armed jaws, the snoek shows a preference for small food such as krill, anchovies, pilchards, other small fish and squid. There is considerable seasonal variation in the condition of snoek and during late winter and in spring, the fish is normally in a poor state of health. This coincides with the breeding season and is associated with the low oil and protein content of its flesh. The nematode parasites which heavily infest the boy do not, however affect the quality of the fish. Sexual maturity is attained at a length of about 60cm and the juveniles frequently use protected areas such as False Bay.
Capture
Most snoek are caught by commercial fishermen, using fish-baited hanlines, but the species is equally popular with sport anglers though rarely with spearfishermen. The snoek is well respected by all who catch it as it is extremely vicious and once hooked, it is rapidly retrieved and immediately killed to avoid lacerations. The flesh makes excellent eating, freshly cooked, dried or smoked.
Specific Catch Restrictions
Open Species: Minimum legal size is 60cm total length. For many years a closed season was observed but this has been lifted, but should not be regarded as a sign that stocks are inexhaustible. Care should be taken not to over-exploit the species during this period when most specimens are reproductively ripe.
