Effect of parasitic sea lamprey on profile drag of lake trout: consequences for swimming (#25)
The sea lamprey (Petromyzon marinus) is an invasive species in the Great Lakes system, it is deemed a major cause of the collapse of the lake trout (Salvelinus namaycush) in this system. This species is characterized as an aggressive predaceous behavior, feeding on blood and ﬂuids of several fish species. This parasite-host interaction may affect kinematics of locomotion of fish. The objective of this study was to determine how the presence of attached sea lamprey on the body of lake trout affect profile drag. The trout and sea lamprey models were generated from 3D laser scans (NextEngine HD, 400 dpi scan resolution) of frozen specimens or morphologically accurate carved models. For both models, point-cloud data was rendered to a closed model and printed as components in ABS plastic (MakerBot Replicator 2X). The trout model was instrumented with a custom made load cell oriented to optimally measure axial (rostral-caudal) force. Drag force measurements, obtained at the Carleton University Water Channel Facility, were then obtained from the model (with and without attached sea lamprey models) in flows from c. 5 cm/sec to 32 cm/sec. Drag from models with sea lamprey models attached was measured for different: 1) ratios between trout total length (Ltt) and lamprey total length (Ltl) (Ltt/ LTl = 1, 0.66, 0.5 and 0.25); and 2) location of attachment of the lamprey on the body of the trout. The information gathered with this study is intended to contribute to the knowledge of the biomechanics of lake trout during host-parasite interaction.