Ichthyofauna in the Lomami National Park and Its Hinterlands, Democratic Republic of the Congo

This investigation deals with freshwater fish populations in thirteen sampling rivers of Lomami National Park (LNP) and its hinterlands. The study aimed to inventory the ichthyofauna in freshwater bodies of LNP and its hinterlands; determine fish species with high economic value according to preference by riparian communities; and assess the conservation status of fish species. Intensive fish sampling was conducted thirteen rivers of LNP and its hinterlands using gill nets with stretched mesh sizes of 9.5, 10, 12, 15 and 20 mm in 2016. A survey questionnaire was administered to fishermen in order to determine fish species with high economic value.  A total of 2985 fish were caught in thirteen rivers belonging to 129 species, 54 genera, 20 families and 8 orders. The family of Mormyridae dominated in the fish collection with 30 species followed by family of Alestidae with 23 species. Clarias spp., Schilbe spp., Chrysichthys spp., Auchenoglanis occidentalis, Polypterus spp., Hydrocynus spp., Alestes spp., Parachana spp. and species of Mormyridae were recorded as fish species with high economic value. The majority of species was least concerned, but one was reported as endangered species (Nannothrissa sterwarti) and another vulnerable (Labeo rectipinnis). The analysis displayed that all rivers were diverse with a minimum observed in the Onema River. The probability of catching two individuals of different species in the same river was high in all rivers, but it was higher in the Amboko, Lodja, Lomami and Yalo Rivers (96%); and it was slightly low in the Onema River (73%). The Kruskal–Wallis result showed statistical differences among sampling rivers (P = 0.0000). Our findings provided valuable information for the conservation and management of fish species in the freshwater of Lomami National Park and its hinterlands

Preliminary Data on Biology of Stomathorinus Cf Polli Matthes, 1964 of Masendula Stream (Kisangani, RD Congo)

Background and aim: Stomatorhinus cf polli, one of species of Mormyridae whose flesh is highly appreciated by local communities. Unfortunately, there is very little information about biology and ecology of Stomatorhinus cf polli. This study aimed to determine the ecology and biology of Stomathorinus cf polli.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Methods: The circular dip scoop net of 0.5 mm of mesh and the amplifier were used during twelve months. 260 specimens of Mormyridae were collected in a single site of Masendula stream. All fish samples were weighed using scales, as well as each fish were measured using a tape measure and caliper. Diet and reproduction were analyzed. &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;&nbsp;Results: The analysis of 151 stomach contents of Stomatorhinus cf polli allowed identifying three prey categories (animal detritus, vegetable detritus and chironomidae). The diet of Stomatorhinus cf polli expressed in the coefficient of occurrence showed that individuals feed the same prey but in different proportions. The mean intestinal coefficient calculated for specimens of Stomatorhinus cf polli is 0.58. This species prefers more to consume animal detritus. For reproduction, the findings showed that this species breeds throughout the year. The mean relative fecundity is 25,125 oocytes per kg.</p

Preliminary Data on the Taxonomic Composition and the Spatio-Seasonal Variation of the Zooplanktonic Population of Fish Ponds in Kisangani, DR Congo

The overall objective of this study was to determine the taxonomic composition and spatial seasonal variation of the zooplankton population in fish ponds in Kisangani, DR Congo. The collection of zooplankton in fishponds was carried out using plankton nets in the Artisanal and Plateau boyoma districts for four months, two months per season. At the end of this study, 3 sub-classes, 13 families and 22 species were listed. The subclass Monogononta (Rotifers) was the best represented with 7 families and 14 species identified. On the other hand, the family Brachionidae was the richest with 6 species. The high specific richness of zooplankton according to site and season was recorded in the Artisanal district with 19 species and in the rainy season with 22 species. Thus, it should be noted that the fish ponds of Kisangani have a high specific diversity of zooplankton that can vary according to the sites and seasons. Certain species such as Tropocyclops prasinus prasinus, Moina macrocopa, Brachionus falcatus, Thermocyclops sp and Brachionus calyciflorus are more abundant than others present. However, the list of species presented is not exhaustive given the sampling period, which was only 4 months, and the collection effort, which was only carried out at two sites.</jats:p

Length-weight and length-length relationships of 48 Senegalese freshwater fish species based on collection specimens.

Length-weight and length-length relationships were calculated for 48 species of freshwater fishes occurring in Senegal, based on 3352 collection specimens. The values of parameter b of the length-weight regression equations were high, with several species exceeding the threshold value of 3.4, pointing to positive allometry. However, size-dependent preservation effects may be the cause of these high values of parameter b, and only one or a few cases represent true allometry. Differences in parameter b between length-weight estimates based on standard length and total length were related to caudal fin allometry. Form factor calculations for the species studied largely coincided with expected and observed overall body form, except for one species. The results suggest that collection specimens can be used to generate length-weight relationships for species that are otherwise difficult to access, or as a preliminary estimate of length-weight relationships. However, these length-weight relationships should be used with caution due to various and variable effects of preservation, and may not be readily comparable to results based on fresh specimens