We estimate the optical signal for an oceanographic lidar from the one-dime
nsional transient (time-dependent) radiative transfer equation using the di
screte ordinates method. An oceanographic lidar directs a pulsed blue or gr
een laser into the ocean and measures the time-dependent-backscattered ligh
t. A large number of parameters affect the performance of such a system. He
re the optical signal that is available to the receiver is calculated, rath
er than the receiver output, to reduce the number of parameters. The effect
s of albedo of a uniform water column are investigated. The effects of a sc
hool of fish in the water are also investigated for various school depths,
thicknesses, and densities. The attenuation of a lidar signal is found to b
e greater than the diffuse attenuation coefficient Bt low albedo and close
to it at higher albedo. The presence of fish in the water is found to have
a significant effect on the signal at low to moderate albedo, but not at hi
gh albedo.