The department shall examine all conduits; and order the owner of a conduit to install, and it is the duty of such an owner to install, a screen on the conduit when, in the opinion of the department, a screen is necessary to prevent fish from passing into the conduit.
Except as provided in Sections 5987, 5988 and 5989, one-half of the expense of constructing or installing a screen shall be paid by the owner of a conduit and one-half by the department.