Early life history traits of Harpagifer antarcticus (Harpagiferidae, Notothenioidei) from the South Shetland Islands during austral summer

The Antarctic spiny plunderfish Harpagifer antarcticus is a common species distributed along the southern Scotia Arc, representing one of the most important components of the littoral benthic fish community there. Compared to adulthood, the early life history traits of H. antarcticus are poorly known, especially for the population inhabiting the shallow waters off the South Shetland Islands. Through the analysis of sagittal otolith microstructure, we estimated age and growth from early larvae collected during the austral summer at Chile Bay, Greenwich Island. An exponential model fitted to the age-length data provided estimates of hatching size and mean larval growth of the local population, being, respectively, 5.36 mm and 0.17 mm day- 1 (range 0.12-0.22 mm day- 1), corresponding to a daily percentage increase in body size of 2.2%. Back-calculated hatch dates were positively correlated to wind intensity, especially in case of northeast wind dominance. Based on this evidence, we suggest that hatching of H. antarcticus might be triggered by wind-induced turbulence in nearshore subtidal environments of the South Shetland Islands. From an ecological perspective, the early life history strategy of this species consisted of a spring-summer hatching of small, fast-growing larvae, which develop into a demersal juvenile stage before their first winter of life.