Oldřich Kopecký

Risk assessment of the crayfish pet trade based on data from the Czech Republic

The pet trade in freshwater crustaceans, including crayfish, has grown rapidly in recent decades and become an important pathway for introducing new non-indigenous species into Europe. This paper provides the first overview of non-indigenous crayfish species (NICS) traded as ornamental and their potential impact in the Czech Republic, which is the second leading importer into Europe. The paper presents a full list of traded crayfish species, their market availability, and trade names or misnomers used in the country. In total, 27 crayfish species from all three families are advertised and marketed, of which Astacus astacus is the only indigenous species. Only three NICS were recognized as very common on the market. The invasiveness and risk associated with ornamental crayfish trade were assessed using the Freshwater Invertebrate Invasiveness Scoring Kit. Five NICS were classified into the high-risk category, the highest score being for Procambarus fallax f. virginalis. The invasiveness of crayfish indigenous to North America is significantly greater than that of crayfish from the rest of the world, and therefore regulation in this regard is recommended.

EUROPEAN HUB FOR INVADERS: RISK ASSESSMENT OF FRESHWATER AQUARIUM FISHES EXPORTED FROM THE CZECH REPUBLIC

Background. The aquarium fi sh trade is characterized by an enormous number of species. Aquarium fi sh may have an impact on native biota by means of their invasiveness as well as through pathogen transfer. The Czech Republic has become a gateway for aquatic pets into the European Union. The aims of this study were to identify the most common aquarium fi sh species on the wholesale market, to estimate temperature suitability for seasonal (winter and summer) survival in the EU, and also to assess the invasiveness risk of the most common aquarium fi shes with the strongest temperature matching. Materials and methods. Data on aquarium fi sh species, their origin, and availability from producers and traders based in the Czech Republic were collected based on all available sources. The target area was defi ned as all member states of the EU. Estimation of the temperature suitability for each species was done using Climatch 1.0 software. The Freshwater Fish Invasiveness Screening Kit (FISK) was employed for species with temperature suitability within the target area exceeding 10% in the coldest quarter of the year. Results. In total, 1118 fi sh species representing 51 families were identifi ed. Thirty-three species belonging to 13 families were classifi ed as “very common”. Three sources of origin were identifi ed: domestic production within the EU, farm production outside the EU, and wild harvests in the region of origin. The major suppliers outside the EU are in south-east Asia. Only one common species originated from wild harvests. FISK scoring divided the 11 species evaluated as having the strongest temperature suitability in the EU (TSEU) into seven species bearing medium risk and four species representing high risk. The family Cyprinidae was the most frequently represented among all evaluated taxa (seven species), but the majority of high-risk fi shes belonged to the family Poeciliidae (three species). The highest score was earned by Carassius auratus (Linnaeus, 1758). Conclusion. The risk potential of aquarium fi shes most traded in the EU seems to be not alarming. Attention should be focused on the possibility of novel pathogen transfer to native aquatic biota as an important aspect of regulating the aquarium fi sh trade.

Aquarium molluscs as a case study in risk assessment of incidental freshwater fauna

Because biological invasions may cause loss of biodiversity, accurate predictions are necessary for implementing effective restrictions aimed at specific high-risk taxa. The majority of freshwater macroinvertebrate invaders are molluscs and crustaceans. The pet trade has been considered one of the main pathways for new introductions of such species. Risk assessment is usually focused on traded ornamental species whereas, despite their potential importance, incidental “hitchhiking” molluscs are usually given only minimal consideration. We surveyed the Czech Republic, which is one of the leading markets for aquarium species in the European Union (EU), and found 41 freshwater mollusc species (25 ornamental gastropods, 6 ornamental clams, and 10 “hitchhiking” gastropods) representing 13 families. We extrapolated data from the Czech Republic and, using Climatch v. 1.0, matched the climate in each species’ native range to the entire territory of the EU. We also assessed the risk associated with each species by FI-ISK. “Hitchhiking” gastropods were found to be significantly more hazardous and with higher potential to become established within the EU than were ornamental gastropods and bivalves. Many “hitchhikers” may be easily overlooked due to their small size and cryptic coloration or shape. Thus, they easily can be accidentally imported in association with aquarium plants. Therefore, we recommend here to disinfect imported ornamental plants to eradicate these unwanted faunal assemblages.

The effect of sex ratio on size-assortative mating in two explosively breeding anurans

Size-assortative mating (SAM) is a widespread phenomenon related to individual fitness. In our study, we examined: (i) the appearance of SAM, and (ii) the effect of sex ratio on intensity of SAM in wild populations of two explosively breeding anurans, common frogs, Rana temporaria, and common toads, Bufo bufo. Despite a higher male-biased operational sex ratio (OSR) in toads, the body lengths of the paired males and females were significantly correlated only in frogs. Increasing male-male competition, assessed via the OSR, resulted in a stronger correlation also in frogs only. Thus, great variability in the presence and intensity of SAM has been observed within both studied species.

Bioaccessibility versus Bioavailability of Essential (Cu, Fe, Mn, and Zn) and Toxic (Pb) Elements from Phyto Hyperaccumulator Pistia stratiotes: Potential Risk of Dietary Intake

Aquatic weeds are widely used as animal feed in developing countries. However, information about element bioavailability from these plants is lacking. A combination of an in vitro method [physiologically based extraction test (PBET)] and an in vivo feeding trial was used in this study to investigate potential element bioaccessibility and estimated bioavailability of Pistia stratiotes (PS). Cu, Fe, Mn, Zn, and Pb concentrations in PS biomass, artificial gastrointestinal fluids, and rat tissues were determined using atomic absorption spectrometry with electrothermal atomization and inductively coupled plasma-atomic emission spectrometry. PS exhibited elevated Fe, Mn, and Pb levels. The PBET revealed high bioaccessibility of all monitored elements from PS biomass. The results of the in vivo trial were inconsistent with those of the PBET, because animals fed PS exhibited low levels of essential elements in the tissues. The consumption of a PS-supplemented diet significantly decreased total Fe levels and increased the total level of accumulation of Pb in exposed animals. Significantly reduced amounts of essential elements in the intestinal walls indicated a potential disruption in nutrient gastrointestinal absorption in animals fed PS.

Composition and Scaling of Male and Female Alpine Newt (Mesotriton Alpestris) Prey, with Related Site and Seasonal Effects

In amphibians, most species are female-biased sexually dimorphic and such dimorphism is often accompanied by intersexual differences in prey composition. While many aspects of foraging ecology have been studied in this group, intersexual differences have rarely been described. We examined dietary composition of male and female Alpine newts (Mesotriton alpestris) from two localities in the Czech Republic during the entire breeding period by stomach flushing, lsopoda, Cladocera, Rana eggs were the most, important prey. About 16% of newts did not. contain prey items. At studied localities, females were about 15% larger than males. Snout—vent length (SVL) of newts was related to the mass of consumed prey, but not its number and diversity. Analyzing the residuals from the relationships between SVL and prey characteristics, we found the effect of sex on all observed prey variables — the females consumed more prey items, more diverse prey and also in greater mass than did the males.

Metabolic transformation and urinary excretion of selenium (Se) in rats fed a Se-enriched defatted rapeseed (Brassica napus, L.) diet

Se-Enriched defatted rapeseed (Se-DRS), a by-product of rapeseed oil production, is high in Se. This study aimed to detect possible changes in Se-metabolism after Se-DRS consumption and to assess its suitability as a Se supplement in monogaster feed. In this experiment, rats were fed three types of diets differing in Se-form: soybean meal, Se-salt and Se-DRS. Potential differences in Se-metabolism were evaluated based on the total Se concentrations along with non-protein Se speciation patterns in the urine and blood serum of the rats. The total Se concentrations were determined using inductively coupled plasma-mass spectrometry (ICP-MS). Se compounds in the samples were identified through high-performance liquid chromatography/ICP-MS. The total Se excretion rate was dose-dependent, and excess of dietary Se was eliminated in the form of Se-sugar 1, regardless of the administered Se-form. The excretion dynamics of dietary selenomethionine (soybean meal) and methylselenocysteine (Se-DRS) were different to that of the mineral Se (Se-salt). The proportions of Se species in the urine were significantly influenced by the Se source. A specific metabolic pathway, resulting in urinary excretion of Se-sugar 2, was observed in animals fed Se-DRS. Neither the total Se concentrations nor the serum Se speciation patterns differed between the animals fed the conventional diet and those fed the Se-DRS-enriched diet. Based on these results, Se-DRS can be considered a suitable Se supplement for monogaster nutrition in Se-deficient regions.

Lavender, Eucalyptus, and Orange Essential Oils as Repellents Against Ixodes Ricinus Females

Abstract This study evaluated the repellent effect of three essential oils against females of Ixodes ricinus, which is considered to be the main arthropod disease vector in Europe. The essential oils could be regarded as user- and environment-friendly alternatives to synthetic repellents. As a comparison sample, the most widely used synthetic repellent DEET was used. All the tested oils exhibited moderate to high initial repellency of 65-85% 5 min after application. The testing was terminated after 80 min, when lavender and eucalyptus repelled 45% and 15% of ticks, respectively. No effect of orange oil was observed after a 20-min mark. The effect of DEET was found to be high and stable (95-100%) throughout the experiment. This study thus revealed that the investigated oils are not as effective as DEET. On the other hand, especially lavender showed an interesting potential as an alternative repellent for outdoor activities of shorter duration.

Sex differences in ventral side colouration of Alpine newts

Sexual selection based on visual stimuli was recently studied in several amphibian species with permanent or temporary dichromatism. The Alpine newt (Ichthyosaura alpestris) is a Caudate species with prominent sexual dichromatism during the breeding period. We focused on the intersexual differences in the orange, carotenoid-base ventral colouration of this widespread European species. We used an image analysis approach to compare the content of the red colour and saturation of the belly in 80 male and 62 female aquatic adult newts captured during spring migration in two localities in the Czech Republic. Both studied colour parameters of the ventral side of the Alpine newt are connected with sex. Males have significantly higher values of saturation on both localities, but the relationship with red content was not so clear. Individual characteristics (body condition, body length) affect colour variables of males and females similarly. Effect of body condition on colour variables was not demonstrated. Theref...