Violet cod (Antimora rostrata) are a bycatch of the longline fishery for toothfish (Dissostichus mawsoni and D. eleginoides) in the Ross Sea, Antarctica. The productivity of this species in Antarctica was unknown, so counts of zones visible in sectioned otoliths of A. rostrata were used to estimate growth parameters. Von Bertalanffy parameters (with 95 % confidence intervals) derived for male and female fish combined are L ? , 82.2 ± 20.9 cm total length; K, 0.047 ± 0.034 year -1 ; and t 0 , -0.6 ± 6.0 years. Violet cod in the Ross Sea appear to have low productivity; they are slow-growing and relatively long-lived, with a maximum estimated age of 41.5 years. There was no apparent difference between sexes in length at age, although males are poorly represented in the longline catch. The growth rate of violet cod in Antarctic waters appeared to be faster than for the same species around New Zealand, about 20°of latitude to the north. The growth parameters must be considered preliminary because the otoliths are quite difficult to interpret, the sampled fish do not represent the full-length distribution of the population (i.e. small fish were absent), and the ageing technique has not been validated.

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The grenadiers Macrourus caml and M. whitsoni form a significant bycatch component of longline fisheries for Antarctic toothfish (Dissostichus mawsoni) in the Southern Ocean. A lack of species-level biological and catch data has to date hindered the development of quantitative assessments for these deepwater species. This paper examines species- and sex-specific life histories of M. caml and M. whitsoni in the Ross Sea region, Antarctica, from samples collected from the commercial fishery and research collections. Macrourus caml was found to live longer, grow slower, and attain a larger maximum length than M. whitsoni, reaching at least 65 years of age and 97 cm total length (TL) vs. 43 years and 78 cm TL for M. whitsoni. In addition, M. caml attains a larger length for a given age and a greater weight for a given length. For each species, females of a given age were larger and reached a greater maximum age than males. Assuming that selectivity of the fishing gear is related to fish size, greater fishing pressure on females than males is likely, and was evidenced by female-biased sex ratios of both species. Estimates of natural and fishing mortality rates were low for both species. Despite having a shorter lifespan and attaining a smaller maximum length, M. whitsoni matured later in life and at larger lengths than M. caml. Although sampling opportunities are constrained seasonally due to sea ice cover, gonad staging and interannual patterns in gonadosomatic indices suggest prolonged spawning for both species, with available data indicating peak spawning during austral summer. The differences in life history observed between these two closely related and morphologically similar species illustrates the importance of understanding species-specific life histories to infer responses to exploitation, provide key biological inputs to inform parameters for future risk assessments and ecosystem models as well as baseline information for comparative work over both time and space, contribute to greater clarity in managing fisheries that interact with these two species, and further our understanding of grenadier life history.