6533b7d9fe1ef96bd126ce6e

RESEARCH PRODUCT

Selection of spawning substratum by European river lampreys (Lampetra fluviatilis) in experimental tanks

subject

description

The selection of spawning substratum by the river lamprey (Lampetra fluviatilis) was studied in two experimental tanks with different flow conditions. In both tanks, four gravel sizes mixed with 15% sand were available to the test animals. In the tank with the lower current speed, lampreys selected in favour of the finest (2–8 mm) gravel size available against gravel sizes 4–20 mm and 8–40 mm. Selection was also significantly different in the tank with higher current speed where selection against the medium-sized substratum (4–20 mm) was evident, but there were no differences between selection for gravel sizes 2–8 mm, 2–40 mm and 8–40 mm relative to availability. Substratum selection and observation of the behaviour of lampreys constructing nests suggest that lampreys may use a wide variety of gravel sizes as spawning substratum as long as they are able to excavate a nest depression by waggling their tails and/or by carrying gravel particles out of the nest with their oral disks and/or with the aid of the...