Fecundity of the lampreys Lampetra hubbsi and Eudontomyzon hellenicus

Abstract

This is the first report on the fecundity in adults of two nonparasitic lamprey species at risk, the Vulnerable Kern Brook Lamprey, Lampetra hubbsi and the Critically Endangered Macedonia Brook Lamprey, Eudontomyzon hellenicus. The mean absolute fecundity of L. hubbsi was 1865 eggs and that of E. hellenicus was 994. The higher fecundity in L. hubbsi was directly related to its higher mean gonadal mass (0.90 g) relative to that in E. hellenicus (0.52 g). Based on preserved museum material possessing well-developed primary and secondary sexual characters, the spawning period for L. hubbsi was inferred to be February-March and for E. hellenicus to either extend from January to May or to occur as separate events; one in January and the other in May. Because metamorphosing ammocoetes of E. hellenicus have been collected in October and in January, it is hypothesized that those metamorphosing in October spawn in January and those metamorphosing in January spawn in May. These periods need to be corroborated with field observations. Evidence for E. hellenicus spawning in January is based on the presence of spent females of this species collected in that month.