Fig. 4. Seawater temperatures at McMurdo Station. Seawater temperatures were recorded from August 2002 to March 2004 at 40 m depth near a spawning site of G. acuticeps at the McMurdo Station. Arrows indicate approximate hatching and spawning dates for the yearly cohorts. G. acuticeps spawns in mid-November and embryonic development is protracted across c. 10 months. Hatching is in early September, near the start of the austral spring. The seawater is within 0.05°C of its freezing point (-1.91°C) between June and December, and shows little variation in temperature with depth during this period.