Gut content analysis of marbled lungfish obtained from lake Wamala wetland system.

Abstract

This study was conducted on lungfish obtained from Lake Wamala, at Katiko and Bukanaga landing sites, both of which are located in Mityana district, and are affected by pollution from anthropogenic activities. Gut content analysis is important for providing information for monitoring and maintaining functional wetland ecosystems because it provides insight into fish feeding patterns and quantitative assessment of food habits which enhance fisheries management by availing basis for understanding trophic interactions in aquatic food webs. Lungfish were harvested using longlines (hook no.7) and some samples were obtained from gillnets (3.0, 3.5, 4.0 and 4.5 mesh sizes). The fish were weighed and total gut length was measured. The relative condition factor of lungfish ranged from 0.37 to 0.64 with a mean value of 0.47 (±0.02 SE) indicating a fair condition of the fish. The length-weight relationship showed a linear proportionality with a calculated r-value (0.9140, P < 0.001, df = 17) indicating a positive allometric growth, and the length-weight relationship described by the equation: log W = -5.83 + 3.17 log TL. The lungfish were dissected and guts were harvested. The guts were split open and an analysis of food items in the gut of marbled lungfish, Protopterus aethiopicus from Lake Wamala wetland ecosystem, using the frequency of occurrence method showed other fishes form the largest portion of lungfish diet as evidenced by 92.3% occurrence of fish skeletal remains in the gut of lungfish. The other food items consumed by marbled lungfish included: mollusks, insects, detritus, crustaceans, worms and plant material. Conclusively, longlines are efficient at catching mature lungfish. Other fishes and macroinvertebrates contribute to contents in the gut of lungfish, and the fair condition of the fish maybe attributed to poor water quality in sampling sites. However, the usage of alternative bait like offal on longlines and active community participation should be enhanced to protect and conserve the lake.