Pond depth was later measured in the middle of the pond using a measuring
stick and at points 2maway fromthe pond edge. Generally ponds had a
flat bottom and depth varied little (0.05–0.2 m) once the sloping sides
reach the maximum depth less than 2 m from the pond edge. Seven
ponds had depths in the range 0.4–0.5 m, 9 ponds 0.6–0.7 m, 14
ponds 0.8–0.9 m, 10 ponds 1.0–1.1 m and the remaining 20 ponds had
depths in the range 1.2–1.3 m. To confirm the pond characteristics we
visited all selected ponds while they were emptied in preparation for
the next stocking of fry. Surface area of the ponds ranged from 300 to
5000 m2. Pond volume was estimated by assuming that average depth
in the section from the pond edge to 2 m from the edge was 0.7 of the
depth in the middle of the pond.