Habitat modifications by sea lampreys (Petromyzon marinus) during the spawning season: effects on sediments

Abstract

This study evaluated the habitat modifications of sea lampreys (Petromyzon marinus) during their spawning season. Males are responsible for digging circular or oval shape nests with lengths varying between 0.80 and 2.25 m (mean 1.49 m ± 0.43 SD). Females join later during the final phase of the process. Nest depth varies between 0.20 and 0.40 m (mean 0.28 m ± 0.07 SD). Significant differences in the mean particle size of the sediments were detected (F = 126.7; P < 0.01); sediments from the edge of the nest were coarser than the control plots, and sediments from the center of the nest were the finest. This species clearly changes the sediments in the spawning areas by altering the structure of the riverbed, with possible reverberating effects on other organisms. The burrows created by the sea lampreys remained intact for several months despite significant daily changes in the current velocity due to upstream dam operations. Given these results, and recognizing the great ecological importance of this species worldwide, their spawning activities should be taken into account in future ecological studies.