Morphometric changes during growth of the brook lamprey lampetra reissneri
Tsuneki, K.; Ouji, M.
Japanese Journal of Ichthyology 31(1): 38-46
ISSN/ISBN: 0021-5090 Accession: 005934588
The brook lamprey (L. reissneri) was collected at the Hosshoji River, Tottori Prefecture, Japan, once a month for 1 yr. Metamorphosing individuals were collected in autumn and immature adults in winter. Ammocoetes larvae were collected throughout the year. From size-frequency histograms, the larval period was estimated to be more than 3 1/2 yr. Ammocoetes larger than 160 mm in total length were always female. Metamorphosing and adult females were larger than corresponding males. This may mean that at least some females metamorphose 1 yr later than males. In ammocoetes, the relative prebranchial and branchial length decreased and the relative tail length increased during growth. Egg diameter increased rapidly during metamorphosis.