Diet of 300 specimens of Bryconaethiops boulengeri from Djiri River (Congo Brazzaville) caught with cash nets was studied according to the size of fish, sampling stations and hydrological season. Sampling focused on t...Diet of 300 specimens of Bryconaethiops boulengeri from Djiri River (Congo Brazzaville) caught with cash nets was studied according to the size of fish, sampling stations and hydrological season. Sampling focused on twelve annual withdrawals made during three years. The relative importance index combining numerical and weight percentages of occurrence was calculated and also the sex ratio was evaluated. Bryconaethiops boulengeri consumes terrestrial and aquatic insects and everything that falls into the water (birds feathers, plant debris, fruits, etc.). The percentage of emptiness is 9.66% of the three sampling stations selected;no significant difference in diet was observed whatever the season.展开更多
The diet of from the lower Djoue River was determined by the size of the specimens and the sampling season. Stomach contents of 662 specimens caught monthly from September 2012 to August 2013 were examined. The size o...The diet of from the lower Djoue River was determined by the size of the specimens and the sampling season. Stomach contents of 662 specimens caught monthly from September 2012 to August 2013 were examined. The size of the individuals varies between 15.37 and 109.52 mm, for a mean 49.95 ± 8.3. Of the stomachs analyzed, 145 were empty, representing a vacuity coefficient of 22%. The food spectrum of C. polli consists mainly of algaes (Ip = 65%) and plant debris (Ip = 11%). A plasticity of the diet is observed according to the size, at sizes greater than 69.17mm (Classes 5-7), a gradual change in diet was observed with entomophagous and ichthyophagous tendency. The diet varies little according to the seasons;the algaes are the main preys in the dry season and insects during the rainy season. The food composition and the intestinal coefficient value showed that Ctenochromis polli is herbivorous.展开更多
文摘Diet of 300 specimens of Bryconaethiops boulengeri from Djiri River (Congo Brazzaville) caught with cash nets was studied according to the size of fish, sampling stations and hydrological season. Sampling focused on twelve annual withdrawals made during three years. The relative importance index combining numerical and weight percentages of occurrence was calculated and also the sex ratio was evaluated. Bryconaethiops boulengeri consumes terrestrial and aquatic insects and everything that falls into the water (birds feathers, plant debris, fruits, etc.). The percentage of emptiness is 9.66% of the three sampling stations selected;no significant difference in diet was observed whatever the season.
文摘The diet of from the lower Djoue River was determined by the size of the specimens and the sampling season. Stomach contents of 662 specimens caught monthly from September 2012 to August 2013 were examined. The size of the individuals varies between 15.37 and 109.52 mm, for a mean 49.95 ± 8.3. Of the stomachs analyzed, 145 were empty, representing a vacuity coefficient of 22%. The food spectrum of C. polli consists mainly of algaes (Ip = 65%) and plant debris (Ip = 11%). A plasticity of the diet is observed according to the size, at sizes greater than 69.17mm (Classes 5-7), a gradual change in diet was observed with entomophagous and ichthyophagous tendency. The diet varies little according to the seasons;the algaes are the main preys in the dry season and insects during the rainy season. The food composition and the intestinal coefficient value showed that Ctenochromis polli is herbivorous.
