Effects of the 2022 Oder River environmental disaster on fish gill structure.

The 2022 Oder River disaster was one of the most significant harmful events in recent European river history, with an estimated 60% reduction in fish biomass in the lower section of the river. While the prevailing hypothesis attributes associated fish kills to toxins from golden algae Prymnesium parvum, our histopathological study on the gills of 2 common cyprinid fish species, namely vimba bream Vimba vimba (L.) and roach Rutilus rutilus (L.

Brown trout in Oder estuary tributaries: genetic structure, stocking, and admixture.

Several rivers that are tributaries of the Oder estuary are inhabited by Salmo trutta L, the most important of which are Ina, Gowienica, and Wołczenica. Both forms of the species, sea trout and resident brown trout, are present. All rivers are traditionally stocked with either sea trout from the neighboring Pomeranian river Rega basin or resident brown trout from various locations.

Early Ontogeny of Cichlids Using Selected Species as Examples.

The purpose of this study was to characterize in detail the reproductive strategy, course of embryogenesis, and development of larvae in three species of fishes of the genus : the green terror (), the red discus (), and the jaguar cichlid (). Eggs for the study were obtained from five pairs of each species (300 eggs from each female) and incubated at 26 °C. The developing eggs were observed under a microscope (Carl Zeiss Stereo Discovery.

sp. and Other Parasites of Migrating and Rare Fish Species in the Southern Baltic Sea and Coastal Waters, Poland.

The present study is the first to analyse the parasite fauna of sole , dab , hake , whiting , and plaice in the Pomeranian Bay, as well as saithe from the Szczecin Lagoon (Poland). The aim of this study was to determine the occurrence of parasites in migrating and rare fish in the Pomeranian Bay and the Szczecin Lagoon and to determine the composition of the diet of these fish. The fish for analysis were obtained in the years 2010-2019.

Histomorphometric evaluation of melanomacrophage centers (MMCs) and CD3 T cells of two morphs of brown trout (Salmo trutta) fed diets with immunostimulants.

The brown trout (Salmo trutta) is a salmonid residing in riverine and coastal waters throughout the Northern Hemisphere, whose various populations evolved into distinct ecological morphs, differing in their migratory tendencies and preferred habitats. Unfortunately, due to progressing degradation of natural environment, the conservation of these populations is of growing importance and is undoubtedly a challenging task. Therefore, various means to refine the preparatory protocols for restocking using hatchery-reared fish are being pursued, some of which involve the administration of immunity-boosting substances.

The gill monogenean Sciadicleithrum variabilum induces histomorphological alterations in the gill tissues of the discus Symphysodon aequifasciatus.

High mortality is among the most serious problems and challenges in the ornamental fish trade. Examination of the discus Symphysodon aequifasciatus from ornamental fish hatchery revealed infestation with the monogenean Sciadicleithrum variabilum. Gill infestation with this monogenean induced serious damage to the gill lamellae, including clavate lamellae, vascular congestion in the peripheral blood vessels, lamellar blood sinus dilation, and other structural anomalies.

The Effect of an Anthropogenic Magnetic Field on the Early Developmental Stages of Fishes-A Review.

The number of sources of anthropogenic magnetic and electromagnetic fields generated by various underwater facilities, industrial equipment, and transferring devices in aquatic environment is increasing. These have an effect on an array of fish life processes, but especially the early developmental stages. The magnitude of these effects depends on field strength and time of exposure and is species-specific.

Magnetoreception in fish.

Magnetoreception is the ability of organisms to perceive magnetic fields in the surrounding environment and changes in its properties such as field direction, intensity and gradient, where the effect on organisms can manifest as an array of reactions. As the magnetic sense is found in many taxa, both evolutionarily young and old, it can be assumed that magnetoreception came into existence as one of the first sensory systems. Many studies on the effect of magnetic fields on fishes have considered both fishes that migrate for long distances and those that are more or less sedentary.