Age, growth and size at sexual maturity of Macrourus carinatus caught as by-catch in Australian sub-Antarctic trawl fisheries
Estimates of age and growth were obtained from 156 Macrourus carinatus otolith samples collected during two research voyages to Heard and McDonald Islands (Division 58.5.2) in 1992 and 1993. The range of estimated ages was 4 to 25 years. There were no significant differences in growth parameters calculated for males and females. Von Bertalanffy growth parameters for both sexes combined were: L∞ = 690 mm, K = 0.069 and t0 = -2.4. The size at sexual maturity of M. carinatus was determined from 162 specimens collected during commercial trawl fishing operations in the Heard Island region in 2000. The length at first maturity (L50) was 418 mm (total length) and the length at first spawning (Lm50) was 511 mm (total length), for both sexes combined. The length–weight relationship for M. carinatus from Heard and McDonald Islands was statistically different to that from Macquarie Island. Otolith and body size relationships are presented for M. carinatus from Heard and McDonald Islands.