Timescale of ovarian maturation in Notothenia coriiceps; evidence for a prolonged adolescent phase
Ovarian maturation in Notothenia coriiceps is known to include a period during which yolk deposition begins to take place. This ‘adolescent’ phase was thought originally to last for about 1 year. The results from a 2–year study at Signy Island indicate that this adolescent phase lasts for about 4 years. There is also some evidence to indicate that not all sexually mature fish spawn each season. Two reproductive strategies are considered, one where adverse conditions are accompanied by a failure to spawn and an alternative where fecundity is controlled by the number of small oocytes which ripen.