bstract. The fish leech Johanssonia arctica (Johansson, 1898) was collected from king crabs Paralithodes camtschaticus Tilesius, 1815) in Finnmark, N Norway, and allowed to feed on experimental fish hosts in the laboratory. This leech ingested lood from laboratory-reared cod (Gadus morhua) and halibut (Hippoglossus hippoglossus). Some experimental halibut acquired rypanosome infection, with par...

We studied life-history characteristics of 22 genetically distinct Daphnia hyalina 3 galeata clonal lineages isolated from samples taken at different depths in the Schöhsee Lake (Germany) in the presence and absence of fish kairomones. Substantial genetic variability was observed for all traits investigated. The presence of fish kairomones had a significant effect on all traits except relative ...

Visual predation by nocturnal zooplanktivorous fish is assumed to be sufficiently limited to allow the evolution of vertical migration as means for predation avoidance by zooplankton. However, in situ measurements of predation rates by nocturnal fish are lacking. Most of our knowledge of this predation is based on stomach contents and laboratory experiments. Our objectives were to measure the i...

We present a UBV CCD photometric study of four open clusters, NGC 7245, King 9, IC 166 and King 13, located between l = 90◦ and 135◦. All are embedded in a rich Galactic field. NGC 7245 and King 9 are close together in the sky and have similar reddenings. The distances and ages are: NGC 7245, 3.8 ± 0.35 kpc and 400 Myr; King 9 (the most distant cluster in this quadrant), 7.9 ± 1.1 kpc and 3.0 G...

Choanoflagellates are the closest living relative of animals (Alegado, 2014; King, 2015; King 2016; Rokas, 2008). This has been confirmed through multiple lines of phylogenetic analyses, comparative genomics, and similarities in cell biology (Alegado, 2014; King, 2001). Previous studies of the choanoflagellate Salpingoeca rosetta suggest that bacteria may have played an important role in the ea...

Discus is one of the ornamental fish that lives in freshwater. a quite famous among lovers. (Symphysodon discus) belongs to Cichlidae family which comes from calm waters Amazon river. This also known as King Aquarium. Its body shape round like disc and its movements are smooth. enthusiasts numerous, they creative bring up new varieties better more attractive, demand by public. All strains discu...