Wiesław Świderek

The popularity of exotic animals, including turtles, kept as pets, has grown steadily in recent decades. Limited awareness of the biological and ecological requirements of these species, combined with insufficient regulation in the pet trade, has contributed to frequent cases of release into the wild. Consequently, the risk of the introduction of non-native turtle species has increased; while not all introduced species establish viable populations or compete with native fauna, some compete for habitat and food resources, transmit pathogens and parasites, or disrupt ecosystem functioning. This study assessed the availability and prevalence of problematic turtle species in the Polish pet trade. Data were collected in 2024 from three main distribution channels: zoological fairs, pet shops, and online platforms, resulting in 1001 recorded observations. A total of 15 freshwater and 11 terrestrial turtle species were identified. The most frequently offered were members of the genus Pseudemys (49.5%) and Mauremys reevesii (13.84%)—both potentially invasive taxa already recorded in natural environments of several European countries. Additionally, species prohibited from trade in Poland, such as the pond slider Trachemys scripta and the false map turtle Graptemys pseudogeographica, were found among online listings, constituting a total of 3.03% of all observations. These results highlight a significant risk of further introduction of alien turtles into Poland’s natural environments, posing a serious threat to biodiversity, including the endangered native European pond turtle Emys orbicularis. Urgent public education and additional legal regulations are needed for the pet trade to prevent the further spread of invasive turtle species in Poland and across Europe.

The aquarium trade is one of the main pathways for the introduction of non-native freshwater species. Such species include crayfish, which are valued ornamental animals commonly kept in aquaria. Some crayfish have been released into the environment, becoming invasive alien species. Due to the threat they pose to biodiversity and related ecosystem services, they have been subject to legal restrictions as invasive alien species of Union concern. In Poland, examples of species that have entered aquatic ecosystems this way include red swamp crayfish Procambarus clarkii and the marbled crayfish Procambarus virginalis. Given the highly developed aquarium pet trade in Poland, a detailed analysis of the availability of crayfish in the pet trade was conducted. This study examines the presence and sale of crayfish at locations at zoological trade fairs, shops, and online marketplaces in Poland. Additionally, pricing, the volume of imported crayfish, and their welfare in the year 2024 are presented. Crayfish were recorded in all surveyed locations. In shops and zoological trade fairs, five crayfish species were recorded, including the invasive alien species P. clarkii and C. destructor. Online advertising platforms featured 15 crayfish species, of which four were invasive alien species. Cambarellus patcuarensis was the most commonly sold species in all examined places. Crayfish were often kept in poor condition. Furthermore, many sellers probably disguised the species of crayfish being sold illegally. This work shows that trade in invasive alien crayfish species is still widespread in Poland.

This article presents new observations of the invasive signal crayfish, Pacifastacus leniusculus , in Poland. The species was detected for the first time in the Lutynia and Prosna rivers in southwest Poland. In total 59 and 50 individuals were captured. The population examined probably came from illegal releases, while the presence of juvenile specimens may suggest that the population is capable of reproduction. This species could continue to spread and expand its range to include additional aquatic ecosystems. Therefore, it is recommended to monitor the environment regularly and take appropriate remedial actions against this population.

This contribution presents the occurrence of epibiotic species associated with Neocaridina davidi shrimp collected in the wild, aquaculture ponds, and aquaria. A total of 900 shrimp are imported from Taiwan, three-quarters of which host at least one of the recorded epibionts. Among those epibionts, two species new to science are discovered, Cladogonium kumaki sp. nov. and Monodiscus kumaki sp. nov., while the other two, Holtodrilus truncatus and Scutariella japonica, are redescribed. The largest number of epibionts is found in shrimp collected from aquaculture ponds and the lowest in individuals from aquaria. Epibiont occurrence differs across designated microhabitats. The epibionts may be introduced alongside their host outside their native range, and their presence may affect shrimp breeding rates. Thus, more control over them should be provided. Their spread can be limited by removal from the host during molting or manually, as well as by using interspecies interactions.

High stocking densities, closed animal houses, and elevated concentrations of bacteria, fungi, and the products of their activity, including ammonia and hydrogen sulphide, have adverse health effects. Active techniques used to reduce unfavourable environmental conditions, such as ventilation, sprinkling, bedding sorbents, and nutritional treatments, are not always sufficient to improve the animals’ living environment. The current paper aims to evaluate the effect of radiant catalytic ionization (RCI) on airborne microorganisms, cage microbiological status, gaseous ammonia concentrations, and the haematological status of mice in animal houses. After one week of operation of an RCI system, the number of airborne bacteria and fungi in the experimental room decreased in comparison to the first day of the experiment (p < 0.05 and p < 0.05 respectively), as did the concentrations of ammonia (p < 0.01) and dust. At the same time, the basic health parameters of the mice, determined in the blood, were very similar between the control and experimental room. RCI seems to be an ideal solution to ensure high hygiene standards in animal rooms and houses with limited use of disinfectants or antibiotic treatment of sick animals. An additional, environmental benefit is the limited amount of nitrogen released.

We hereby provide the first documented data on the occurrence of a viable Procambarus virginalis population in a nature reserve in Poland and the steps that were taken to prevent further introductions of the species in the country. To date, Poland represents the most north-eastward distribution area in Europe, where the species occurs in ecosystems with natural water temperature regimes. The ecological plasticity of P. virginalis and its obligate parthenogenetic reproduction make this crayfish an exceptional invader. The crayfish may have detrimental effects on the native invertebrates, amphibians, and fish, and alter the state of the entire ecosystem. Therefore, we investigated the presence of the species in the nature reserve of Pojezierze Łęczyńskie Landscape Park after a suspected P. virginalis individual was found by a local citizen. The nature reserve also includes an area designated to protect native amphibians and turtles. Our study revealed the presence of a thriving population of P. virginalis in the protected area and clear indications of its impact on native and invasive species, both in aquatic and terrestrial environments. If no action is taken, the species will likely expand to other water bodies across the country. An extensive sensibilization campaign allowed us to find additional invaded areas and significantly contribute to the effective ban of this and other invasive crayfish species from private and commercial online trade. Raising public awareness and banning invasive crayfish species trade is essential for successfully detecting and preventing further introductions.

In the European Union, aquarium pets are organisms intended for closed places (e.g., pet shops, garden ponds, home aquariums). Until April 2021, regulations did not require veterinary inspection of these animals within the EU, although there is a potential risk of such organisms being released into the environment along with their symbiotes or parasites. Currently, a “disease-free” declaration is required, but no aquarium snail pathogen that needs attention in international trade has been included in the list of potential hazards. Here, we intended to check whether molluscs from the pet trade could be a source of parasites. We answered this question by using Anentome helena, a popular commodity in the ornamental pet industry, as a research model. Snail specimens were randomly collected from aquarium pet stocks imported from Bangkok (Thailand) to Warsaw (Poland) in March 2020. In total, three specimens were subjected to histological examination and 27 specimens were autopsied. Histological analysis revealed that one snail was infected with rediae (and the cercariae inside them). Our study is the first to show the presence of digenean larvae in A. helena originating from the ornamental pet industry. The spread of such “hitchhikers” in non-native areas will likely be associated with threats to environmental and public health. Therefore, it is necessary to constantly draw public attention to the possible consequences of releasing ornamental pets into the non-native environment.

The main microbial contaminants of rooms in which laboratory rodents are housed are bacteria and fungi. Restriction of microbial growth to below threshold levels requires the application of various sophisticated antimicrobial techniques that must be effective and safe for the animals. Some of the most commonly used techniques, including chemical disinfection, ventilation, filtration, sterilization and radiation, are not always sufficiently effective. The aim of the current study was to evaluate the efficacy of a modern technique (i.e. radiant catalytic ionization (RCI)) on the microbiological status of an animal care facility, and the health of the mice housed therein. The experiment, conducted over seven days, compared an experimental room with an RCI system permanently turned on with a negative control room. At the completion of the experiment, the number of bacteria in the RCI room air and on its walls was lower than that in the control room ( p < 0.01 in both cases). Values of the basic prooxidative parameter, thiobarbituric acid reactive substances concentration, in tissues of mice from the RCI room were within allowed boundaries. Hence, application of an RCI system proved to be an ideal technique to ensure high hygienic standards in animal rooms without any adverse effects on the animals housed therein.

This contribution presents the first record of ornamental shrimp epibiont, Scutariella japonica (Platyhelminthes: Temnocephalida) in European waters. The species lives on freshwater Atyidae shrimp from temperate, subtropical and tropical zones of South-East Asia. In total, 120 individuals of Neocaridina davidi shrimp were caught in thermally polluted canal of Oder river, near the city of Gryfino, in the northwest part of Poland. In that group, 5.83% were infected with scutariellids. Among shrimp, females were mostly infected (85.71%). Since ornamental shrimp released into thermally polluted water bodies have been also noticed in surrounding waters of natural temperature regime in Europe, S. japonica may spread further following potential expansion of the Neocaridina shrimp in Oder river. It is possible that other crustaceans, both native and alien which are present at this location, may also become vectors of this epibiont.