02411nas a2200241 4500008004100000022001400041245014100055210006900196260001600265300001200281490000900293520162800302653002101930653002701951653001501978653003701993653002002030100001902050700001602069700001402085700001802099856005202117 2025 eng d a2658-351800aLength-weight relationships and condition factors of Mormyridae species in the Niger River: implications for conservation and management0 aLengthweight relationships and condition factors of Mormyridae s cJan-01-2025 a215-2210 v20253 a

The length-weight relationship and condition factor of the ten most abundant Mormyridae species in the Niger River at Niamey were examined from August to November 2023. The species assessed were Mormyrus rume, Campylomormyrus tamandua, Pollimyrus isidori, Brienomyrus niger, Hyperopisus bebe, Mormyrus macrophthalmus, Mormyrops anguilloides, Brevimyrus niger, Mormyrops oudoti, Cyphomyrus Psittacus, and Marcusenius cyprinoides. Analysis of their length-weight relationships revealed “b” values ranging from 2.08 to 2.87, suggesting negative allometric growth across all species. Condition factor (k) values varied from 1.22 ± 0.31 for H. bebe to 10.48 ± 2.83 for M. cyprinoides, with no significant differences in average condition factors among the species. These findings highlight the potential vulnerability of Mormyridae species to environmental changes and anthropogenic pressures, emphasizing the need for targeted conservation measures. The results underscore the importance of sustainable fisheries management practices to preserve biodiversity and ensure the long-term productivity of the Niger River ecosystem. The observed negative allometric growth patterns indicate that environmental conditions may be suboptimal for these species, potentially due to factors such as habitat degradation, water quality issues, or overfishing. Addressing these challenges through habitat restoration and regulatory measures could enhance the resilience of fish populations and support sustainable fisheries.

10acondition factor10alength-weight analysis10aMormyridae10asustainable fisheries management10athe Niger River1 aSouley, S.M.N.1 aHarouna, M.1 aAdo, M.I.1 aYoussoufa, I. uhttps://doi.org/10.31951/2658-3518-2025-a-2-21501729nas a2200193 4500008004100000245015000041210006900191300001000260490000700270520108100277653002901358653001201387653003001399653001501429653001501444653001201459100001501471856004901486 1989 eng d00aDistribution, abundance, size and feeding habits of Brienomyrus brachyistius (Gill, 1862) (Teleostei: Mormyridae) in a Nigerian rainforest stream0 aDistribution abundance size and feeding habits of Brienomyrus br a25-360 v133 a

Brienomyrus brachyistius (Gill, 1862) constitutes 64% of the total number of all mormyrid species caught from the upper and middle reaches of Ikpa River in the rainforest zone of south-eastern Nigeria. It inhabits shallow marginal areas and swamp-pools with aquatic macrophytes. B. brachyistius feeds primarily on benthic invertebrates (with chironomid larvae predominating), algae, detritus and secondarily on zooplankton, miscellaneous invertebrates and mud/sans; allochthonous invertebrates and macrophyte material are of incidental importance. The diet varies slightly with growth and season. Feeding activity is higher in the small-sized guild (< 10 cm TL) than large-sized guild (≥ 10 cm TL); it is intense at night but declines during the day and is higher in the dry season than during the rains. Seasonal fluctuations in hydrometeorological regimes (rainfall, water level, flow rate) are critical factors that affect the food and feeding habits of the fish; flood has a depressive influence on food variety and feeding intensity.

10aBrienomyrus brachyistius10aecology10aHydrometeological regimes10aIkpa River10aMormyridae10aNigeria1 aKing, R.P. uhttps://doi.org/10.26028/cybium/1989-131-00302056nas a2200241 4500008004100000022001400041245014300055210006900198260001600267300001100283520124300294653003801537653002201575653001801597653001801615653001501633653002801648100002401676700001801700700002301718700002401741856004901765 2024 eng d a0380-133000aBiogeographic barriers are differentially permeable based on traits: Movement of hypoxia tolerant mormyrid fish in the Lake Victoria basin0 aBiogeographic barriers are differentially permeable based on tra cNov-01-2024 a1024853 a

Lake Nabugabo is a small satellite lake separated from Lake Victoria by hypoxic swamps that impose a biogeographic barrier to fish assemblages. Some species occur exclusively in Nabugabo while others show high differentiation across this barrier, yet air-breathing fishes show nearly zero genetic differentiation between the two lakes. We hypothesize that hypoxia-tolerant fishes, unlike other non-air-breathing species, would have similarly low genetic differentiation across the barrier. We used pooled RAD-seq to examine the degree of genetic differentiation in two species of non-air-breathing but hypoxia-tolerant mormyrid fishes, Marcusenius victoriae and Petrocephalus degeni. Other non-air-breathing fishes have been shown to have FST values as low as 0.05 but mostly between 0.10 and 0.20; however, we discovered that the genetic differentiation in our focal species was very low, with FST values between 0.02 and 0.04, making them much more comparable to air-breathing fishes with FST values of near zero. We conclude that this and other analogous barriers should be understood as differentially permeable depending on the traits of the organisms crossing them, such as hypoxia tolerance in this case.

10aDifferentially permeable barriers10aHypoxia tolerance10aLake Nabugabo10aLake Victoria10aMormyridae10aPopulation connectivity1 aHunt, David, A.G.A.1 aThomas, Quinn1 aClarke, Shelby, B.1 aChapman, Lauren, J. uhttp://dx.doi.org/10.1016/j.jglr.2024.10248502377nas a2200277 4500008004100000245015600041210006900197260001800266300001000284490000600294520155800300653001701858653001101875653001201886653001301898653001501911653002101926100001801947700001401965700001501979700001701994700001402011700001602025700001202041856004602053 2024 eng d00aDiet of some fish species of the family Mormyridae (Actinopterygii: Teleostei; Bonaparte, 1831) from the upper Sanaga River, Central Region of Cameroon0 aDiet of some fish species of the family Mormyridae Actinopterygi c31 March 2024 a51-620 v63 a

This study was carried out between October 2020 and October 2021 with the aim of determining sustainable management options and nutrition for the domestication of Mormyridae fish species living in the Sanaga River in central Cameroon. For this purpose, 451 specimens collected from local fishermen were identified and grouped into four genera and seven species, constituting 20.84% Campylomormyrus phantasticus (Pellegrin), 5.32% Hippopotamyrus castor (Pappenheim), 24.61% Mormyrops anguilloides (Linnaeus), 18.63% Mormyrops caballus (Pellegrin), 4.66% Mormyrops zanclirostris (Günther, 1867), 15.52% Mormyrus rume (Valenciennes), and 10.42% Mormyrus tapirus (Pappenheim). Fish were measured, and parameters were obtained after dissection using intestinal morphometric characteristics and stomach content analysis methods. The emptiness coefficient varied from 0% (Hippopotamyrus castor and Mormyrops zanclirostris) to 26.66% (Mormyrus rume). The relative mass of the intestine was low in all studied species; the intestinal coefficient and the Zihler index of all these species are within the range of carnivorous species. Analysis of stomach contents revealed a broad food spectrum containing twelve categories of prey. Insects, macrophytes and larval insect shelters were the preferred foods of Mormyrops anguilloides, Mormyrops caballus and Mormyrops zanclirostris, while insect larvae and larval shelters were the preferred prey for other species. Site and season had little effect on the categories of prey consumed by these species.

10aBiodiversity10aEbebda10afeeding10aMonatele10aMormyridae10astomach contents1 aAkohogni, MAM1 aMedjo, KE1 aZebaze, TB1 aChiassa, NKA1 aMepa, TCP1 aTiogué, TC1 aFon, ED uhttp://dx.doi.org/10.22034/JAD.2024.6.1.502056nas a2200265 4500008004100000022001300041245015000054210006900204260001600273520114000289653002001429653002801449653002001477653001501497653002801512653002501540100002301565700002201588700002201610700002701632700002301659700002101682700002101703856006601724 2016 eng d a1055790300aSpecies delimitation and phylogenetic relationships in a genus of African weakly-electric fishes (Osteoglossiformes, Mormyridae, Campylomormyrus)0 aSpecies delimitation and phylogenetic relationships in a genus o cJan-04-20163 a

African weakly-electric fishes (Mormyridae) are able to communicate through species-specific electric signals; this feature might have favoured the evolutionary radiation observed in this family (over 200 species) by acting as an effective pre-zygotic isolation mechanism. In the present study we used mitochondrial (cytb) and nuclear (rps7, scn4aa) markers in order to reconstruct a species-phylogeny and identify species boundaries for the genus Campylomormyrus, by applying inference methods based on the multispecies coalescent model. Additionally, we employed 16 microsatellite markers, landmark-based morphometric measurements, and electro-physiological analyses as independent lines of evidence to the results obtained from the sequence data. The results show that groups that are morphologically different are also significantly divergent at the genetic level, whereas morphologically similar groups, displaying dissimilar electric signals, do not show enough genetic diversity to be considered separate species. Furthermore, the data confirm the presence of a yet undescribed species within the genus Campylomormyrus.

10aCampylomormyrus10aGeometric morphometrics10aMicrosatellites10aMormyridae10aMultispecies-coalescent10aSpecies-delimitation1 aLamanna, Francesco1 aKirschbaum, Frank1 aErnst, Anja, R.R.1 aFeulner, Philine, G.D.1 aMamonekene, Victor1 aPaul, Christiane1 aTiedemann, Ralph uhttp://linkinghub.elsevier.com/retrieve/pii/S1055790316300781