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The tributary rivers of Lake Tana are important nursery grounds for larvae and juveniles of the migratory endemic Labeobarbus species, but very little is known about their functional habitat and feeding preferences. This study investigated nursery grounds, habitat shifts, and potential energy sources for juvenile Labeobarbus species. Electrofishing point abundance sampling for juvenile sampling and stable isotope ratios of carbon (delta C-13) and nitrogen (delta N-15) were applied to trace potential energy sources. Habitat use shifting was observed among labeobarbus size classes from weak or no flow pool to fast-flowing riffle mesohabitats. The young-of-the-year (YOY) were mainly found in microhabitats with a weak to moderate water velocity (i.e., < 0.3 m s (1)), while 1(+) juveniles (>7 cm FL) adapted to velocities of > 0.3 m s (1). Juveniles suffered from limited access to run and riffle habitats during the peak dry season (March-April). They were subsequently exposed to resource competition and predation risk which led to lower catches. Juveniles of different size classes used different food sources. C1 (7 cm) on zooplankton. Insect larvae were a relatively important source for larger juveniles. Maintaining appropriate flow that permits juveniles to access preferred foraging and nursery habitat in the Gumara River is crucial for the sustainable management and conservation of the Labeobarbus population in Lake Tana. (C) 2022 The Author(s). Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). The authors acknowledged the Belgian Development Cooperation (VLIR-UOS) funding this research through the InterUniversity Cooperation of Flemish and Bahir Dar Universities (IUC-BDU). Bahir Dar University’s VLIR-UOS project staff are acknowledged for the support and logistics provided. We thank Felegush Erarto (MSc student) for her effort and assistance in data collection. We also thank Dr. Zita Kelemen and Yannick Stroobandt (KU Leuven) for their help with stable isotope measurements.

Widespread populations of the invasive species Lithobates catesbeianus (American bullfrog) are present in different parts of the world and are difficult to control. This study investigated the possibility to sterilize male individuals of this species in order to use the sterile male release technique in controlling these invasive populations. The technique can be adopted in aquaculture facilities as well to prevent new introductions by incidental releases or escapes. In order to produce sterile individuals a cold and pressure shock protocol were used on fertilized eggs to create triploid individuals. The cold shock did not result in triploid individuals while 54% triploids were obtained from pressure shock, the remaining individuals being aneuploid. The triploid and control larvae were reared for more than one year and the control larvae had a greater length after 7 and 9 months, their weight did not differ. At metamorphosis no difference in length and weight was found between the two groups. The subadult bullfrogs from both groups showed 9 months post metamorphosis a similar scaled body mass index but lower than individuals living in the wild. The pressure shock protocol needs further refinement in respect to the timing of the shock. Further research on the reproductive behavior of these sterile frogs is necessary to evaluate the possible use in the sterile male release technique. PXL University College and EU Interreg IV A project IVAVLANED- 2.31

Nine adult American bullfrogs (Lithobates catesbeianus) were tagged with an internal radio transmitter and tracked during one year in the valley of the Grote Nete (Belgium). The mean +/- SD core range area (KDE50) was 15.00 +/- 22.41m(2). The home range area (KDE95) had a mean +/- SD of 429.78 +/- 510.97m(2). Shores of larger eutrophic ponds and small temporary pools in alluvial forest were chosen as habitat. The total area used (MCP95) had a mean of 11,086.73 +/- 12,239.00m(2). The study revealed a mean action radius of 270.78 +/- 199.17m and individuals moved up to 742m in a single displacement. These results show that the dispersion of the American bullfrog in a valley system such as the Grote Nete can proceed very rapidly. A positive correlation between weight and distance covered within one movement was found, which could suggest that dominant individuals are capable of covering greater distances in search of optimal habitat for reproduction, foraging or hibernation. This study was financed by the EU Interreg IV A project IVA-VLANED-2.31 "Invasieve exoten in Vlaanderen en Zuid-Nederland-INVEXO" and the PWO-project "EXOUT" of University College PXL.

Pig manure results in the release of NH3, NOx, volatile organic compounds and odour nuisance. Pyrolysis of dried pig manure can be considered as an economical viable approach converting this agricultural waste into value added products. The produced amendment biochar can be used as a slow release fertilizer with high concentration of N, K and P and has beneficial effects as carbon sequester and improver of soil quality and crop productivity. It is proved that a 2 wt.% blending of biochar with a poor soil affects positively plant growth and crops (dwarf beans), and worm (Eisenia fetida) survival and production. Additional, available heavy metals are immobilised in the biochar and not leachable. The resulting biochar therefore offers prospects as low cost, slow release soil conditioner and fertiliser for a long term effect. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors

The potential use of biochar from olive mill waste for in situ remediation of metal contaminated soils was evaluated. Biochar was mixed with metal contaminated soil originating from the vicinity of an old zinc smelter. Soil–biochar mixtures were equilibrated for 30 and 90 days. At these time points, Ca(NO3)2 exchangeable metals were determined, and effects of the biochar amendment on soil toxicity were investigated using plants, bacteria, and earthworms. Bean (Phaseolus vulgaris) growth, metal content, antioxidative enzymes activities, and soluble protein contents were determined. Furthermore, effects on soil microbial communities (activity, diversity, richness) were examined using Biolog ECOplates. After 120 days of soil–biochar equilibration, effects on weight and reproduction of Eisenia foetida were evaluated. With increasing biochar application rate and equilibration period, Ca(NO3)2 exchangeable metals decreased, and growth of bean plants improved; leaf metal contents reduced, the activities of antioxidative stress enzymes decreased, and soluble protein contents increased. Soil microbial activity, richness, and diversity were augmented. Earthworm mortality lowered, and their growth and reproduction showed increasing trends.

The ultrastructural organization of the proboscis in two species of free-living Platyhelminthes, Psammorhynchus tubulipenis and Cytocystis clitellatus is very alike but differs from previously described species. Both sheath and cone epithelium are composed of two circumferential belts. Only the basal cone epithelium is syncytial, while no nuclei were found in the distal belt of the sheath epithelium. The sheath epithelium is characterized by numerous infoldings of the basal plasma membrane. The nuclei present in the bulb belong to the proximal belt of the sheath epithelium and the apical cone epithelium. Nuclei of the basal cone epithelium are located insunk behind the proboscis bulb. The insunk cell parts pierce the septum of the bulb laterally near the proximal end. Different types of gland necks and sensory cells pierce the epithelia. Associated with the distal belt of the sheath epithelium, two sensory organs are found, containing multiciliary receptors with modified axonemata. Differences in organization of the proboscis musculature are described and compared with the organization in other species. The systematic position of both species is discussed in the light of the new findings.

The ultrastructural organization of the proboscis in Mesorhynchus terminostylis is distinctly different from that in other members of the Polycystididae in which it is currently classified. The sheath epithelium is formed by three belts, all with intra-epithelial nuclei. The apical belt of the bipartite cone epithelium has a single intrabulbar nucleus, and the basal belt possesses five insunk nucleiferous cell parts behind the bulb. Six types of glands surface through the epithelia; the three types emerging through the cone epithelium can be homologized with those described for Polycistis naegelii. Only uniciliary receptors are found in the epithelium. The musculature in the bulb has a very loose appearance, and the bulbar septum appears to be a bipartite basement membrane. The septum can be considered the basement membrane of the cone epithelium as if the contractile portion of the inner longitudinal muscles have invaded the epithelium and come to lie between the epithelial cells and the basement membrane. Thus the inner musculature of the bulb is entirely intraepithelial as is the case for Psammorhynchus tubulipenis and Cytocystis clitellatus. The systematic position of M. terminostylis remains uncertain but seems to lie between Psammorhynchus and Cytocystis on one hand and Koinocystididae and Polycystididae on the other.