| The time of day can be very important in determining the species that
are present in front of the video cameras. Some reef fish species may
be closely associated with the reef structure and not move far from
it, other species may spend most of their time swimming higher in the
water column or foraging out over the adjacent sand bottom. Open water
species, such as scad, might use the reef for shelter during times of
the day, when large predators are feeding. During the daylight hours
in November, 2002, a predictable change occurred in the fish assemblage
near the bottom habitats. Relatively tranquil schools of juvenile fish
seemed to predominate early and late in the day. Sometime shortly after
mid-day, swarms of scad appeared near the bottom, often in frenzied
swimming. The scad were followed by schools of blue runner, which were
often present for less than an hour. |