Argonauts sometimes come ashore in huge numbers. The reasons for these mass strandings are unknown, with hypotheses including particular combinations of winds and tides, or argonauts following krill schools. Suggestions of a seven year cycle in these strandings are not supported as these animals are likely to have a life span much shorter than seven years.
A beach-stranded female argonaut (Argonauta nodosus). Photo: © Jesse Tucker
In 1982 an estimated 6,300 female argonauts (A. argo) weighing some 600 kilograms were caught in coastal set nets in the western Japan Sea over a two-week period.
Mass strandings of argonaut females have been reported from a number of Australian coastal localities such as Port Phillip Bay and Corner Inlet in Victoria , Thistle Island and Yorke Peninsula in South Australia , Montague Island and Narooma in New South Wales and Flinders Island in Tasmania.
Beach-cast argonaut shells (Argonauta nodosus) collected following a mass stranding. Photo: © Mark Norman