1. Depth equilibration of a shallow-water cichlid fish
- Author
-
B. J. Hill and A. J. Ribbink
- Subjects
Daytime ,Aquatic Science ,Biology ,biology.organism_classification ,Waves and shallow water ,Paleontology ,Oceanography ,Cichlid ,Natural distribution ,Melanochromis ,Pressure decrease ,%22">Fish ,Active value ,Ecology, Evolution, Behavior and Systematics - Abstract
The cichlid Melanochromis exasperatus has a natural distribution which is restricted to a single island in Lake Malawi, Africa. Diving observations indicated that it does not occur below 4.5 m depth. Measurements of depth equilibration in a pressure tank showed that males can equilibrate to a depth of 25 m and females to 18 m. Mean maximum sustained rate of depth equilibration was 2 m day−1. M. exasperatus survived a pressure decrease of 40% every 12 h from the maximum equilibration depth to the surface. The fish swim actively during the day but rest on the bottom at night when they are equilibrated to a depth 1 m deeper than ambient. Reduced activity at night is reflected in a drop in oxygen consumption to nearly half of the daytime active value.
- Published
- 1978