New Zealand Journal of Marine and Freshwater Research abstracts

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EFFECT OF JET BOATS ON SALMON EGGS

A. J. Sutherland
D. G. Ogle

Civil Engineering Department,
University of Canterbury, Christchurch,
New Zealand

Abstract The passage of jet boats through spawning areas can kill salmon eggs buried in the river bed. By using a jet boat on the Ashley River the pressure gradients created in a redd were determined. At the maximum boat speed investigated (11 m.s~') gradients up to 9.32kPa.m ' were recorded. The induced water velocities through the gravel were then estimated from the equation of motion and reproduced in a gravel-filled tube in the laboratory. For the test conditions discharge velocities ranged from 0.18-0.3 m.s-¹. Studies of the effect of these flows on salmon eggs revealed fatality rates of up to 40% at their most critical stage on the ninth day of development.

N.Z. Journal of Marine and Freshwater Research 9 (3) : 273-82.
(Received 4 September 1974; revision received 25 February 1975)

PDF file of entire paper: medium quality (1136K); (scanned from paper original: notes about this process)

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