Jiří Patoka

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• Professor (full)
• Senior Researcher at Czech University of Life Sciences Prague

Ornamental aquaculture and fishkeeping are very popular with millions of enthusiasts worldwide. The number of newly imported fish species for ornamental purposes grew slowly from World War I until the 1980s. It then exponentially increased until now with more than 7900 species and a large number of scientifically undescribed morphotypes. Here we pr...

Cherax pulverulentus sp. nov. is a moderately-sized burrowing freshwater crayfish endemic to the streams west of the Ayamaru Lake in Bird's Head Peninsula (Framu Subdistrict, Southwest Papua Province), the Indonesian part of New Guinea. Although this species has been exploited in the ornamental aquarium trade at least for 21 years, it has not been...

Fish in the South American genus Arapaima Müller, 1843 (hereafter referred to as arapaimas) have attracted interest for commercial aquaculture development thanks to their rapid growth rate and high market value. However, management agencies in the United States have expressed concerns about importing and culturing arapaimas due to records of non-na...

This study shows how YouTube™, a popular video website, is a powerful tool to document and improve our ability to manage freshwater pet release in Brazil. Based on a series of 24 videos chosen randomly using 19 standardized keywords posted by pet-keeping YouTubers between January 1, 2020 and March 20, 2023 (650 h of searching time), we documented t...

Ornamental aquaculture is an economically important industry with many enthusiasts worldwide. Much of the supply for the industry is provided by individuals and businesses in tropical countries because many ornamental species originated in the tropics. But Czechia, a temperate region in Central Europe, is an exception. Czech suppliers have signific...

The ornamental pet trade has emerged as one of the most important pathways for the introduction of non‐native aquatic species. In the last two decades, freshwater crayfish have become a popular ornamental group, with numerous non‐native populations established through this way, including some populations of the North American red swamp crayfish Pro...

A survey was conducted on recently collected specimens of the rare eastern European astacid crayfish, Astacus colchicus. The study included a detailed examination and illustration of external morphology, mandible, gastric mill, and gills. Comparative analysis was carried out by comparing the morphology with other European members of the same family...

Integrated teaching is a widely discussed method of educating pupils and students at all levels of education, including elementary schools. It is a way of connecting the subjects into larger units and explaining to pupils the context and related patterns, and has a “synergistic effect”. Here we present the results of a questionnaire survey and SWOT...

Poster focused on environmental education and biological invasions (in Czech).

The introduction of non-native aquarium fish species has modified the composition of fish assemblages worldwide. This anthropogenic impact alters not only the richness/abundance of local assemblages but also the taxonomic and functional composition among them. To investigate this phenomenon, we conducted a standardized sampling program in degraded...

The methodology comprehensively presents the topic of biological invasions, which are a global threat to biodiversity in the globalised world. The target group is secondary school teachers. The methodology should serve as a theoretical basis for the extension of the science and related subjects and for the implementation of environmental education...

An illustrated story about invasive raccoon.

Freshwater crayfish are amongst the largest macroinvertebrates and play a keystone role in the ecosystems they occupy. Understanding the global distribution of these animals is often hindered due to a paucity of distributional data. Additionally, non-native crayfish introductions are becoming more frequent, which can cause severe environmental and...

Records count per crayfish taxa integrated in WoC platform.

Crayfish and A. astaci records integrated in WoC platform count per major hydrographic basins.

Crayfish and A. astaci records integrated in WoC platform count per country.

1. The Indo-Burma biodiversity hotspot has one of the world's most species-rich inland waters. However, its freshwater biodiversity faces habitat loss and species extinction due to large-scale development of water resources, pollution, exploitation of native biota, and introduced non-native species. 2. These threats include the South American sucke...

Biological invasions cause huge environmental and socio-economic losses worldwide. Among successful invaders, there are also several decapod crustacean species. In this study, we report the presence of an potentially invasive crab species that damages rice crops in Sumatra, Indonesia. This paddy-field crab Parathelphusa convexa DeMan, 1879 is a fre...

Standardized terminology in science is important for clarity of interpretation and communication. In invasion science – a dynamic and rapidly evolving discipline – the proliferation of technical terminology has lacked a standardized framework for its development. The result is a convoluted and inconsistent usage of terminology, with various discrep...

Amazon sailfin catfish are native to Latin Arica (Siluriformes: Loricariidae: Pterygo-plichthys) and are popular around the world as ornamental fish. It is well-documented that these species are highly successful invaders and very prone to forming new geographical ranges. However, once established, eradicating a new population is a very challenging...

Biological invasions are a global threat to biodiversity in the globalised world and education of pupils is perceived to be very important to prevent new introductions of non-native species. The target group of presented methodology is primary school teachers. The methodology should serve as a theoretical basis for the extension of the educational...

The crustacean infraorder Astacidea is represented by two freshwater (Astacoidea and Parastacoidea) and two marine superfamilies (Enoplometopoidea and Nephropoidea). The antennule setation and sternal morphology were examined in specimens of 1) Parastacoidea: Cherax destructor, C. quadricarinatus, and C. tenuimanus from the Australian mainland; Ast...

Standardized terminology in science is important for clarity of interpretation and communication. In invasion science — a dynamic and quickly evolving discipline — the rapid proliferation of technical terminology has lacked a standardized framework for its language development. The result is a convoluted and inconsistent usage of terminology, with...

Cherax woworae n. sp. is a moderately-sized burrowing freshwater crayfish endemic to the Teminabuan District, South Sorong Regency, Southwest Papua Province, Indonesia. This species is one of many freshwater crayfish species from the region that are popular ornamental animals. In the pet trade, it is commonly known as the "Blue Moon Crayfish" or "B...

Fishing is part of human culture since ancient times to catch fish. The use of live bait by anglers is an important factor in the spread of invasive aquatic species. To analyze the habits of Indonesian anglers in using freshwater crayfish as live bait, an anonymous online questionnaire was spread via social media in Indonesia. The questionnaire inc...

The narrow-clawed crayfish Pontastacus leptodactylus is a large native European astacid crayfish species distributed in the drainage area of the Azov, Black and Caspian Seas. The species shows immense morphological diversity across its range. Various species and subspecies have been described and, recently, eight species and two subspecies were con...

Early offspring separation from mothers causes social deprivation. Mouthbrooding, when eggs and fry are incubated in the buccal cavity of the parent, is one of the reproductive strategies in fish. The mother is the incubating parent in African lake cichlids from the genus Tropheus. Many of these are produced in captivity and some producers use arti...

The pet trade is known to be one of the most important pathways of aquatic non-native species introduction and Indonesia is a significant trade partner. Popular ornamental South American river stingrays (Potamotrygon spp.) were introduced to Indonesia in the 1980s and the culture was established. Here we present a detailed Indonesian market and aqu...

Marine fish diversity in Sundar strait is one of phenomena, that are influenced by open sea and close sea system in Java Sea. The highest diversity are related to high productivity and ecosystem health.

The aquarium pet trade is a source of potentially invasive crayfish species, which can be subsequently intentionally or unintentionally introduced into new environments. This can lead to biological invasions that represent a threat to native biodiversity and, in particular, freshwater ecosystem functioning. In global terms, Europe is the most affec...

Invasive species are one of the main causes of biodiversity loss worldwide. Pet trade is a well-known pathway for the introduction of non-native species. Prevention is the most effective, least time-consuming, and least financially demanding way to protect biodiversity against the spreading of invasive species. The main part of prevention is the ea...

For management strategies aimed at biological invasions, a detailed survey of the general public’s knowledge is crucial. For this purpose, our present study aimed to (i) investigate the level of comprehension regarding biological invasions, (ii) assess the ability of responders to discriminate between invasive and native species, and (iii) evaluate...

Both external and internal morphological characteristics (the gastric mill and the gill on maxillipeds) of museum specimens of European Astacidae, namely Astacus astacus and Pontastacus leptodactylus, were observed and detailed illustrations and descriptions are herein provided. Several morphological variations in external morphology were detected,...

Xenophthalmus pinnotheroides is a tiny subtidal marine crab from the West Pacific and Northern Indian Oceans. Its native range is poorly documented, with few records from the wild. Although it is not exploited by humans, degradation of suitable habitats by anthropogenic activities can significantly threaten this species. Here we bring the first rec...

Sense appendages such as long antennae are important in sensory information obtaining for freshwater crayfish but predators, congeners or conspecifics commonly damage them. We described the unusual bifurcation of one long antenna in the wild-collected adult male Cherax cf. boesemani (Decapoda: Parastacidae) which was imported from the Indonesian pa...

Ornamental aquaculture and the related pet industry are known to be important sources of non-native species worldwide. In the temperate zone, thermal waterbodies are attractive places for irresponsible owners to release unwanted freshwater pets including decapod crustaceans. Several non-native ornamental species have been reported in the thermal lo...

The coconut crab Birgus latro (L., 1767), also known as the robber crab, is an endangered terrestrial anomuran facing extinction due to accelerating overexploitation and habitat destruction. It is therefore crucial to develop methods of its culture in captivity. Generally, an artificial diet is beneficial and important to formulate a specific conte...

The African grey bichir Polypterus senegalus is a popular ornamental fish in Indonesia. Pet trade with this species is increasing, and aquaculture production is well established. Here we present a detailed market survey and volume of domestic trade, export and import between January 2018 and February 2021. Climate similarity between the native rang...

Coral reefs are one of the most threatened ecosystems globally. Coral reef ecosystem (CRE) status is an essential indicator in measuring the potential for sustainable management of coral resources in small islands and islets. In this study, the parameters used are coral cover, coral mortality index, and potential exposure. The study was conducted o...

Synanthropic silverfish species have spread over Europe as invaders in recent years. This paper reports the first occurrence of synanthropic silverfish Ctenolepisma calvum in the Czech Republic. Established populations of the species were revealed at two localities in Prague. At both sites, C. calvum occurred inside the buildings with room temperat...

Globally, ornamental aquaculture is a multi-million-dollar industry and popular hobby. There are circa 6700 fish taxa being exploited and traded. Various species are traded under commercial names or codes such as certain armoured catfish of families Callichthyidae (C and CW codes or numbers) and Loricariidae (L and LDA codes). Many of these species...

A new species of highly troglobitic cockroach, Nocticola baumi n. sp., is described from limestone caves of Papua Province, Indonesia. The new species is the first Nocticola reported in New Guinea island and differs from other known Nocticola spp. by the combination of the following characters: compound eyes and ocelli absent, tegmina fully develop...

Synanthropic invasive silverfish, Ctenolepisma longicaudatum, has been recently reported to cause nuisance in the indoor environment in many European countries. To get more details on the species distribution, the species occurrence was monitored by the authors in the countries where establishment of C. longicaudatum has been revealed in the last y...

The pet trade is known to be one of the main sources of invasive species including freshwater crayfish, which cause socioeconomic losses and negative impacts on native biota in many regions where introduced. Indonesia was identified as the leading supplier of ornamental crayfish globally but the local market has been neglected even though certain n...

The South Caucasus (SC) region is recognized for its high biological diversity and various endemic animal taxa. The area has experienced many fish introductions over the years, but the overall information about non-native fishes in the three SC countries, Armenia, Azerbaijan, and Georgia did not exist. Although these three countries belong to the K...

Ornamental aquaculture is one of the main sources of non-native species worldwide. Unintentionally transported “hitchhiking” organisms have been previously recorded; although most of these species are transported from tropical regions, here we report on the first accidental transport of the zebra mussel (Dreissena polymorpha) in a shipment of ornam...

Poster presented in the Symposium for European Freshwater Sciences (SEFS 12), from the study: https://doi.org/10.1111/raq.12531

Indonesia is a tropical country with enormous fish resource potential including both freshwater and marine species. The Ministry of Trade of the Republic of Indonesia noted that at least 240 marine ornamental fish and 226 freshwater ornamental fish were traded as export commodities. The enormous potential supported by the great variability of natur...

There are known plenty tiny invertebrate species associated with decapod crustaceans. Our contribution documents the first record of New Guinean ornamental Cherax crayfish epibiont, Diceratocephala boschmai (Platyhelminthes: Temnocephalida) found in pet trade in the Czech Republic. Correct species assignment was confirmed by genetic barcoding. The...

Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) is a fish from the family Cichlidae, native to Sub-Saharan Africa. Nile tilapia is one of the most cultured freshwater fish species worldwide and because of its commercial value and well-developed aquaculture technologies, it has been introduced to many countries. Nile tilapia also has become inv...

Introduction of non-native species is considered a grave threat for global biodiversity. It can negatively affect native biota and cause serious socioeconomic losses. In this study, we confirmed the existence of black-striped pipefish (Syngnathus abaster) in the freshwater Tbilisi Reservoir (the middle Kura Drainage), which had been translocated fr...

The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment area...

Biological invasions are increasingly recognized ecological and economic threats to biodiversity and are projected to increase in the future. Introduced freshwater crayfish in particular are protruding invaders, exerting tremendous impacts on native biodiversity and ecosystem functioning, as exemplified by the North American spiny-cheek, signal and...

Countless animals, including threatened species from invertebrates to vertebrates, are the victims of the world's largest illegitimate business—illicit sales of wildlife. Botia striata (zebra loach) is an endangered freshwater fish endemic to the Western Ghats of India. Because of its distinctive stripes, it is heavily exported and ranks second in...

Cherax quadricarinatus is a parastacid crayfish native to parts of northeastern Australia and southern New Guinea. It is a relatively large and highly fecund species in comparison with other crayfish of this genus. Since C. quadricarinatus was previously assessed as an invasive species in Indonesia, further monitoring of this species in this region...

Genetics is a promptly developing scientific field. As the genetic methods are evolving, so are sampling procedures. Originally, most of the sampling approaches were severely harming for the subjects, but with improving techniques, a small piece of tissue is enough for the analysis. Currently, it is possible to obtain the sample without damaging th...

The implementation of climate change adaptation for crop production is often ineffective among farmers due to a lack of access to climatic data and inadequate knowledge on how to use the available data. The project introduced the utilization of climate data via the Climate Smart Action "Saung Iklim" application to targeted stakeholders (i.e., agric...

The Infraorder Astacidea comprises four superfamilies of decapod crustaceans: the freshwater Astacoidea and Parastacoidea and the marine Enoplometopoidea and Nephropoidea. The gill morphology of four species of crayfishes belonging to Astacoidea and Parastacoidea, two coral reef species of Enoplometopoidea, and 2 deep-water species of Nephropoidea...

The redclaw crayfish (Cherax quadricarinatus; hereafter redclaw), native to northern Australia and southern New Guinea, is among the largest freshwater deca-pods. It matures early and is considered highly prolific as females may lay over one thousand eggs in a single clutch. Despite generally preferring slow-moving streams in its native range, it h...

Trade with marine species as ornamentals is an important sector of the international pet trade. The vast majority of these species are collected from the wild and one of the top supplying countries is Indonesia. Detailed evidence on trade with marine resources in Indonesia is lacking or it is hardly accessible. Moreover, the exploitation of ornamen...

Ornamental aquaculture is known to be one of the main sources of non-native species and Indonesia has been identified as one of the leading suppliers of these organisms worldwide. Released or escaped ornamental aquatic animals can establish new populations and become invasive. On the other hand, some invasive species can be also endangered in their...

There is a long history of crayfish introductions in Europe and numbers keep increasing. In Hungary, spiny-cheek crayfish Faxonius limosus, signal crayfish Pacifastacus leniusculus, red swamp crayfish Procambarus clarkii, marbled crayfish P. virginalis and Mexican dwarf crayfish Cambarellus patzcuarensis have become established. Here we report on m...

Knowledge of the morphological features of crayfishes native to New Guinea is limited in many cases, the internal morphology, gastric mills, and mandibles of six species of Cherax species (Decapoda: Astacidea: Parastacidae) from this island were described and illustrated. The measurements were compared with those of parastacid crayfish from Madagas...

The pet trade in aquatic organisms is a significant source of non-indigenous species introductions. In comparison with ornamental animals, unintentionally transported invertebrate assemblages are easily overlooked by traders and keepers. Moreover, hitchhiking species detection and identification is difficult even for experts. The densities of "hitc...

The phylogeny of European crayfish fauna, especially with respect to Eastern European species, is still far from being completely resolved. To fill this gap, we analysed most of the European crayfish species focussing on the phylogenetic position of the endemic crayfish Astacus colchicus Kessler, 1876 inhabiting Georgia. Three mitochondrial and one...

The aim of our study was to summarise the current status of the non-native Decapod species in Hungary. Eight non-native Decapod species have been reported recently from Hungary. The first introduced species was the spiny cheek crayfish (Faxonius limosus) found in natural habitats in 1985. The signal crayfish (Pacifastacus leniusculus) also expanded...

Sailfin catfish indigenous to South America are very popular ornamental fish, having previously been introduced to many regions outside their native range. Two species, namely Pterygoplichthys disjunctivus and P. pardalis, are illegal but widespread in Indonesia. They have formed self-sustaining populations, exploited for feeding of domestic animal...

Modern ornamental fishkeeping is one of the most popular hobbies in the world, with various known positive and also negative aspects including the introduction of non-native species. Despite this fact, the history of the first imports of freshwater tropical fish species for ornamental purposes has never been deeply studied and is usually simplified...

1. The large island of New Guinea has a rich indigenous astacofauna represented by numerous parastacids from the genus Cherax. The western half of the island is part of Indonesian territory. 2. Indonesia is known to be the main exporter of ornamental crayfish globally, and certain New Guinean species are exploited as ornamentals within the internat...

New Guinea is the world's largest tropical island, also reaching the highest elevation of any tropical islands, and covering a significant percentage of global biodiversity. Contrary to vertebrate species, invertebrates are mostly poorly studied. The best-known group of invertebrates are butterflies. From aquatic biota, numbers of newly discovered...

This work was presented in European Ichthyological Congress on 6th of September, in Lausanne, Switzerland. Abstract for this work was published online on Frontiers in Marine Science.

Crayfish species are identified both morphologically and genetically. Numerous characteristics are used in morphological analyses. Although, there are known intraspecific variability in rostral shape and length in many crayfish species, some identification keys still use mentioned characteristics as crucial in species determination. Here we present...

The Czech Republic is one of the main importers, exporters and producers of animals for ornamental purpose. Generally, pet trade is not well monitored and the Czech Republic serves as a gateway to import of ornamental animals to Europe. Despite many species of terrestrial gastropods which are known as pests or invaders, the trade with them has not...

The pet trade is one of the most important sources of introduction of freshwater non-native decapod crustaceans. Precise and timely identification of potentially hazardous species is necessary for the effective prevention of new introductions. Here, we present a list of species of ornamental freshwater decapod crustaceans pet-traded in Hungary and...

The pet trade in aquatic animals is known to be one of the main sources of non-native species worldwide. Freshwater decapod crustaceans have increased in popularity as ornamentals in the last two decades. Freshwater crabs of the genus Limnopilos were discovered by hobby aquarists and introduced on the market in 2008. They are generally considered i...

Social deprivation early in life affects further individual development and leads to irreversible behavioural alterations later in life. Although the syndrome is well-studied in vertebrates including humans, its presence in invertebrates has been described only in eusocial insects and cockroaches. Here we show the first evidence of social deprivati...