The "Sapuwa," Bathyclarias nyasensis, is the most abundant and economically important of the dozen species in the endemic clariid flock in Lake Malawi. It is found offshore all over the lake in depths as great as 70 meters, usually being caught in gill nets and almost never on baited longlines (Jackson, 1959). The fish attains a length of one meter (39.4 inches) according to the species account at FishBase.

An outstanding feature of the Sapuwa is the large number of long, closely spaced gill rakers. Counts of from 135 to 246 rakers on the outer arch have been recorded in specimens of 28-80 cm (11-31½ inches) total length, the number being positively correlated with the fish's length (Jackson, 1959). The many gill rakers are apparently an adaptation for straining its chief foods, zooplankton and emerging lake flies (Corethra edulis), from the water. It also eats other insects, and occasionally fish (Jackson, 1959).

B. nyasensis can be distinguished from the other species of Bathyclarias by having all of the following characters (adapted from Greenwood, 1961: 230):

1. Gill rakers long, length of longest gill raker (on outer arch) divided by length of longest gill filament = 0.7-1.0;
2. Body relatively slender;
3. Maxillary barbel contained 1.8-2.2 times in head length; and
4. Gill filaments and epithelium of suprabranchial cavity colorless in preserved specimens.

The illustration is taken from the original description (Worthington, 1933).

Last Update: 18 October 1999 Web Author: M. K. Oliver, Ph.D. Copyright © 1997-2021 by M. K. Oliver, Ph.D. - ALL RIGHTS RESERVED