Growth and the average duration of larval life in the southern hemisphere lamprey,Geotria australis Gray

Summary The average duration of larval life in the anadromous lamprey,Geotria australis (the sole representative of the Geotriidae) is estimated as 41/4 years. Compared with other lampreys, the ammocoetes ofG. australis have a slow growth rate, increase in length during the year preceding metamorphosis and typically enter metamorphosis at a small mean length (<100 mm) and weight (<1.2 g).