habitat_narrative
Marine
Argyrozona argyrozona adults are bentho-pelagic from 50 to 200 m depth and are associated with high profile reef habitats. Juveniles usually occur on inshore reefs from 10 to 40 m depth and move offshore as they reach maturity (Brouwer and Griffiths 2005). The eggs and larvae of A. argyrozona are pelagic and occur inshore of the Agulhas Current (Brouwer et al. 2003). Tagging studies have shown that adults are fairly resident with a small percentage of fish that disperse (Brouwer et al. 2003, Griffiths and Wilke 2002) including some nomadic behaviour involving migrations of more than 100 km (Griffiths and Mann 2000). Adults feed primarily on squid, anchovy and sardine while juveniles feed on crabs, crab larvae, amphipods and polychaete worms (Heemstra and Heemstra 2004). Agyrozona argyrozona can reach 80 cm TL length and live to 30 years of age (Brouwer and Griffiths 2004) and has a maximum recorded weight of 4.1 kg (South African Deep Sea Angling Association 2012).
Reproduction
Argyrozona argyrozona is a serial spawner and a late gonochorist. The size at 50% maturity varied regionally for both males and females; length at 50% maturity for males was estimated at is 22.2 cm FL off the Eastern Cape, 26.1 cm FL off Agulhas Bank, and 29.7 cm FL in the Tsitskamma MPA; for females it was 20.6 cm off the Eastern Cape, 26.7 cm FL off Agulhas Bank, and 29.2 cm FL in the Tsitskamma MPA (Brouwer and Griffiths 2005). The lack of sexual dimorphism in this species and GSI comparisons of males and females suggest that this species exhibits group spawning behaviour (Brouwer and Griffiths 2005). Fecundity, egg size, spawning frequency, and spawning duration were found to be positively correlated to increased body size (Brouwer and Griffiths 2005). Complete (100%) maturity for both sexes occurred at 48 cm FL, an age of about 15 years.
In the Eastern Agulhas Banks spawning occurs from October to May and on the Western Agulhas Banks, from November to May. Nurseries were identified in Algoa Bay on the eastern Agulhas Bank and on the central Agulhas Bank. Juveniles in Algoa Bay dispersed both eastwards and westwards with growth (Brouwer and Griffiths 2005).
Generation length for A. argyrozona is estimated to be 11 years, using the following equation for a gonochorist fish species: Generation length = Σxlxmx/Σlxmx
