Information on the growth of the ammocoete larva of the anadromous Sea lamprey, Petromyzon marinus in British rivers



An examination has been made of the length frequency distribution of ammocoetes of the Sea lamprey, Petromyzon marinus L. collected during April, July, August and October. A comparison of the frequency distributions for the individual collections and a study of gonadal development within certain length ranges suggests that the duration of the larval period cannot be less than five years.