Tag: pet trade

When life gives you zebra mussels

The ease with which this Ponto-Caspian bivalve is being spread by the pet trade on both sides of the Atlantic is a major concern.

Guest blog post by James Dickey

The role played by the global pet trade in the spread of invasive alien species is increasingly gaining attention. Media outlets have excitedly picked up on stories of released goldfish growing to the size of rugby balls, Amazonian catfish appearing in Scottish rivers, and North American crayfish terrorising Tiergarten tourists in Berlin. In recent years I’ve been drawn to these stories, despite the simplistic, repetitive plot: well-meaning but feckless owners can no longer give pets the care they deserve, they struggle to rehome the pets, they release the pets into the wild, chaos ensues.

Pets or threats? Goldfish might be harmful for biodiversity

This happens more than you might think, with pet releases deemed responsible for 53% of invasive vertebrate species and one third of all aquatic invasive species. It has been shown that the more readily available a species is in the pet trade, the greater the risk of it being released, or escaping, into the wild.

Somewhat fascinatingly, this also puts the trade at the mercy of pop culture influences. 1970s animated series “Rascal the Raccoon” is commonly blamed for Japan’s invasive racoon population, and demand for Trachemys scripta pets is said to have boomed in the 1990s due to “Teenage Mutant Ninja Turtles.” Side note: the influence of movies highlighting the challenges of pet ownership, such as “Gremlins” or “Little Shop of Horrors”, warrants further study.

Hitchhikers

While invasion ecology has typically focused on these released species and the impacts that they cause, many species are sold with commensal organisms attached. These incidentally carried fauna are commonly known as “hitchhikers”.

Recent studies have found the protozoan Vorticella sp. and a species of bdelloid rotifer associated with two species of atyid shrimps, digenean larvae with the carnivorous snail Anentome helena, and an epibiont, Diceratocephala boschmai, on New Guinean ornamental Cherax crayfish.

Temnocephalid eggs located on thorax carapace (white arrow) of adult *Cherax monticola*. From Ložek F, Patoka J, Bláha M. 2021. Another hitchhiker exposed: *Diceratocephala boschmai* (Platyhelminthes: Temnocephalida) found associated with ornamental crayfish *Cherax* spp. *Knowl. Manag. Aquat. Ecosyst.*, 422, 25.

A high-profile example emerged in 2021 when zebra mussels (Dreissena polymorpha) were detected in 21 US states on aquarium moss balls that had been imported from Ukraine, and subsequent searches revealed the species in 600 locations in Canada. Similar findings have since emerged from Europe. Having colonised both European and North American waters, the ease with which this Ponto-Caspian bivalve is being spread by the pet trade on both sides of the Atlantic is a major concern. Zebra mussels have been listed as one of the IUCN’s “100 of the Worst Invasive Species”, and their myriad ecological and economic impacts range from habitat alteration, to competition with native unionids, to disruption of food-web structure, to blocking industrial water intake pipes. They are also able to attach to boat hulls and other organisms, facilitating further spread.

The discovery

Zebra mussels, *Dreissena polymorpha*, found amongst ordered European pond snail, *Viviparus viviparus*

I remember the moment clearly. I had ordered seventy-five Viviparus viviparus – a common European pond snail species – for behavioural studies at GEOMAR Helmholtz Centre for Ocean Research Kiel where I was based for lab work in the group of Elizabeta Briski. After some stress over posting delays and an increasingly fraught relationship developing with the GEOMAR receptionist, the snails arrived. Over the next day, watching them go about their lives in our climate chamber in their new tanks became a favourite way to spend working breaks. With obvious dimorphism you could clearly tell males from females, which added to the developing snail soap operas. However, just before packing up to leave the lab, I noticed a huge lump on one snail. What on earth is that? Soon I noticed a second. I called Elizabeta with my suspicions, which she confirmed the next day. Photos were taken, measurements made, and our go-to ecological geneticist Reid Brennan was begged to work his DNA sequencing magic. Before long, it was all confirmed: we had zebra mussels.

Potential implications

The biggest takeaway message here is that even native species in the pet trade can facilitate the spread of non-native hitchhikers. In a parallel universe, those snails did not go to an invasion ecology lab but rather to someone keen to stock their garden pond. Escape from ponds is a major pathway for freshwater species introductions, and even if the impact of a native species escaping might be limited, its potential for the zoochorous dispersal of a non-native should not be ignored.

Of course, questions surround the conditions under which the pond snails were held before selling. Were they stocked in zebra mussel infested outdoor ponds? Which other species are held in a similar way? How prevalent are these practices within the trade? One way of combating this risk of non-native species spread is via legislation. Calls have been made for white lists of low-risk species that can be sold in the trade in place of risky species, but in our study, the issue stems from the selling of a native species within its native range, which would surely be deemed low-risk.

We propose that should a white-list system be adopted, the potential for a “low-risk” species to transport invasive species must be accounted for. We also call for stricter biosecurity practices to be enforced, including regular checking and disinfecting of outdoor stock ponds where appropriate. Tools such as environmental DNA surveillance could be used to effectively detect the presence of targeted invasive species, as part of biosecurity “audits”. However, for the time being, a desperate, final line of defence is to raise awareness amongst consumers and for them to be wary of unwanted hitchhikers.

References:

Dickey JWE, Brennan RS, Chung SS, Jeschke JM, Steffen GT, Briski E (2023) More than we bargained for: Zebra mussels transported amongst European native freshwater snails. NeoBiota 10: 1–10. https://doi.org/10.3897/neobiota.83.97647

DeRoy EM, Scott R, Hussey NE, MacIsaac HJ (2020) Density dependence mediates the ecological impact of an invasive fish. Diversity and Distributions 26: 867–880. https://doi.org/10.1111/ddi.13063

Gippet JMW, Bertelsmeier C (2021) Invasiveness is linked to greater commercial success in the global pet trade. Proceedings of the National Academy of Science USA 118. https://doi.org/10.1073/pnas.2016337118

Lozek F, Patoka J, Bláha M (2021) Another hitchhiker exposed: Diceratocephala boschmai (Platyhelminthes: Temnocephalida) found associated with ornamental crayfish Cherax spp. Knowledge and Management of Aquatic Ecosystems 2020-Janua. https://doi.org/10.1051/kmae/2021023

Militz TA, Foale S (2017) The “Nemo Effect”: Perception and reality of Finding Nemo’s impact on marine aquarium fisheries. Fish and Fisheries 18: 596–606. https://doi.org/10.1111/faf.12202

Padilla DK, Williams SL (2004) Beyond ballast water: Aquarium and ornamental trades as sources of invasive species in aquatic ecosystems. Frontiers in Ecology and the Environment 2: 131–138. https://doi.org/10.1890/1540-9295(2004)002[0131:BBWAAO]2.0.CO;2

Patoka J, Patoková B (2021) Hitchhiking Exotic Clam: Dreissena polymorpha (Pallas, 1771) Transported via the Ornamental Plant Trade. Diversity 13: 1–5.

Patoka J, Magalhães ALB, Kouba A, Faulkes Z, Jerikho R, Vitule JRS (2018) Invasive aquatic pets: Failed policies increase risks of harmful invasions. Biodiversity and Conservation 27: 3037–3046. https://doi.org/10.1007/s10531-018-1581-3

Richardson MJ, Whoriskey FG, Roy LH (1995) Turbidity generation and biological impacts of an exotic fish Carassius auratus, introduced into shallow seasonally anoxic ponds. Journal of Fish Biology: 576–585.

Saul WC, Roy HE, Booy O, Carnevali L, Chen HJ, Genovesi P, Harrower CA, Hulme PE, Pagad S, Pergl J, Jeschke JM (2017) Assessing patterns in introduction pathways of alien species by linking major invasion data bases. Journal of Applied Ecology 54: 657–669. https://doi.org/10.1111/1365-2664.12819

Simberloff D (2006) Risk assessments, blacklists, and white lists for introduced species: Are predictions good enough to be useful? Agricultural and Resource Economics Review 35: 1–10. https://doi.org/10.1017/S1068280500010005

Stanicka A, Maciaszek R, Cichy A, Templin J, Świderek W, Żbikowska E, Labecka AM (2022) Unwanted ‘hitchhikers’ of ornamental snails: A case report of digeneans transported via the international pet trade. The European Zoological Journal 89: 601–607. https://doi.org/10.1080/24750263.2022.2065039

Zeng Y, Shakir KK, Yeo DCJ (2019) Competition between a native freshwater crab and an invasive crayfish in tropical Southeast Asia. Biological Invasions 21: 2653–2663. https://doi.org/10.1007/s10530-019-02009-6

North American turtles establish succcessful populations in Germany, possibly threathening ecosystems

For the first time, self-sustaining populations of three non-native species of turtles were identified in south-western Germany by researchers at the University of Freiburg

Original text published by the University of Freiburg

Three species of turtles native to North America have been successfully reproducing in the wild in Germany, report for the first time environmental researcher Benno Tietz and biologist Dr. Johannes Penner of the University of Freiburg, along with Dr. Melita Vamberger of the Senckenberg Natural History Collection in Dresden.

Their results were published in the open-access scientific journal NeoBiota.

The scientists examined a total of nearly 200 animals living in the wild in lakes in Freiburg and Kehl. Their findings suggest that the turtles have established themselves in a new habitat, where they could become a threat to the local ecosystem.

For two species, this is the first evidence of independent reproduction outside of their natural reproductive range. For the third species, this is the northernmost evidence of its presence up to now,
says Penner.

The false map turtle (*Graptemys pseudogeographica*) enjoys the sun’s warmth. Photo: Johannes Penner.

Turtles released into the wild

Invasive species do a great deal of economic damage world-wide. They also contribute to advancing global species extinctions.

Alien reptiles regularly make their way into the wild in Germany. Most often, this is because they have been released by pet owners.

Large numbers of North American pond sliders (Trachemys scripta) were imported into the European Union (EU) in the 1980s and 1990s as house pets. In 1997, their import into the EU was banned. By 2016, the sale of specimens born here was also made illegal. Since then, pet shops have replaced them with other freshwater turtles, such as the river cooter (Pseudemys concinna) and the false map turtle (Graptemys pseudogeographica).

Genetic analyses of specimens of all three species in a range of ages have now demonstrated that they are reproducing independently in local waters.

What’s surprising is that the invasive species have established themselves so far north. In Europe, successful reproduction and self-maintaining populations of Trachemys scripta were only known in the Mediterranean regions and the continental climate zone of Slovenia,
explains Benno Tietz.

Until recently, it had been assumed the turtles being examined couldn’t reproduce in Central Europe due to the colder climate. Especially the false map turtle is actually quite sensitive to the cold,
he says.

A North American pond slider (*Trachemys scripta*) resting on a lily pad. Photo: Johannes Penner.

Consequences for local species unclear

The invasive turtles could become a problem for indigenous species.

The European pond turtle (Emys orbicularis), for example, is now only present in Germany in parts of Brandenburg.

In an experimental setup, the European pond turtle showed weight loss and an increased death rate when being kept together with Trachemys scripta,
reports Penner.

Penner says that could be caused by the larger, alien species forcing the smaller local turtles from places where they sun themselves, leading the local turtles to have problems with thermoregulation. Or perhaps the competition led to them having greater challenges when seeking food.

Beyond that, aquatic turtles could be hosts for viruses and parasites, leading them to play a role in the spread of diseases. This could potentially have a damaging influence on other parts of the ecosystem, including amphibians, fish, or aquatic plants.

On the other hand, in their study, the researchers consider the alien species could assume functions in damaged ecosystems that would otherwise go unreplaced.

Vamberger says these questions urgently need to be explored further.

We need to raise public awareness that people should not release – no matter what kind of species – any animals into the wild in future.”
she insists.

A river cooter (*Pseudemys concinna*) lets itself drift in the water. Photo: Johannes Penner.

Meet the research team:

Dr. Johannes Penner was the scientific coordinator of the research training group “Conservation of Forest Biodiversity in Multiple-Use Landscapes of Central Europe” (ConFoBi) and a lecturer for the Chair of Wildlife Ecology and Management of the University of Freiburg. Currently, he is a curator at the NGO “Frogs and Friends” and a guest researcher in wild animal ecology.

Benno Tietz has completed a Master’s degree in Environmental Sciences at the University of Freiburg. His thesis – finished in the Winter Semester of 2020/2021 – investigated alien turtles. Currently, he is a research assistant at the Freiburg Institute of Applied Animal Ecology.

Dr. Melita Vamberger is a researcher at the Senckenberg Natural History Collection in Dresden.

***

The study was supported by the Hans Schimenz Fund of the German Society for Herpetology and Terrarium Science (DGHT) as well as the Academic Society of Freiburg.

***

Research paper:

Tietz B, Penner J, Vamberger M (2023) Chelonian challenge: three alien species from North America are moving their reproductive boundaries in Central Europe. NeoBiota 82: 1-21. https://doi.org/10.3897/neobiota.82.87264

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Are people swapping their cats and goldfish for praying mantises?

The first overview of the pet mantis market’s dynamics reports a lack of regulations, but also the potential of a stronger collaboration between hobbyists and scientists for biodiversity conservation.

New research sheds light on the pet insect market and its implications on biodiversity conservation

Rearing insects at home as pets may sound strange, but thousands of people all over the world have already swapped their hamsters for praying mantises or stick insects.

These insects, sold at fairs and pet markets, or collected in the wild and then reared by amateurs or professionals, are gaining increased popularity and fueling a largely unknown market. Not all of them are small, crawling monsters. Some are elegant, with flower-like coloration (the Orchid Mantis, Hymenopus coronatus), and some are funny-looking like Pokémon (e.g. the Jeweled Flower Mantis, Creobroter wahlbergii). Many can be safely manipulated and cuddled as they look at you with big, cute kitty-eyes (the Giant Shield Mantis Rhombodera basalis).

The beautiful orchid mantis Hymenopus coronatus, one of the most priced and requested mantis species on the market. *Photo by* William Di Pietro

When choosing a pet insect, “customers” consider things such as shape, size, colors, and behaviors. They might also take into account how rare a certain species is, or how easy it is to look after. Looking at these preferences, Roberto Battiston of Museo di Archeologia e Scienze Naturali G. Zannato (Italy), William di Pietro of the World Biodiversity Association (Italy) and entomologist Kris Anderson (USA) published the first overview of the mantis pet market. Understanding how this market, which still mostly unregulated, is changing, may be crucial to the conservation of rare species and promoting awareness of their habitat and place in the ecosystem.

A survey among almost 200 hobbyists, enthusiasts and professional sellers in the mantis community from 28 different countries showed that the targets of this market are indeed predictable. The typical mantis breeder or enthusiast, the study found, is 19 to 30 years old and buys mantises mostly out of personal curiosity or scientific interest. Willing to spend over $30 for a single individual, most people prefer beautiful looking species over rare ones.

A cute nymph of the Jeweled Flower Mantis *Creobroter wahlbergii* resting on the tip of a finger. Photo by William Di Pietro

The research, published in the open-access Journal of Orthoptera Research, identified buyers as “mostly curious enthusiasts with poor knowledge of the market dynamics and the laws behind it, even if they seem to generally care about their pet.”

But the data also suggests the trade might not always be on the legal side, as “about one time out of four the lack of permits or transparency from the seller is perceived from the buyer.”

A good collaboration between science and this large community may play a crucial role in the conservation of mantises in nature, the researchers point out.

The Giant Shield Mantis *Rhombodera basalis* looking for a friend. *Photo by* William Di Pietro

Mantises and, in general, insects, are poorly known in terms of biology, distribution, and threats, with many species still unknown and waiting to be discovered. This is a major limit to their protection and conservation, since you cannot protect what you don’t know.

“Hobbyists and pet insect enthusiasts are producing and sharing a huge quantity of observations on the biology and ecology of hundreds of species, even rare or still undescribed ones, a priceless heritage for the scientific community,” the researchers conclude.

“Strengthening the dialogue between them, promoting a white market over a black one, may be a crucial help for the conservation of these insects, fundamental parts of the biodiversity of our planet, that are replacing our traditional pets at home.”

Research article:

Battiston R, Di Pietro W, Anderson K (2022) The pet mantis market: a first overview on the praying mantis international trade (Insecta, Mantodea). Journal of Orthoptera Research 31(1): 63-68. https://doi.org/10.3897/jor.31.71458

Australia’s wish list of exotic pets

In a new study, published in the peer-reviewed open-access scholarly journal Neobiota, scientists estimated the desire of Australians to own non-native and/or illegal alien pets and the major trends in this practice. In addition, the team suggests ways to improve biosecurity awareness in the country.

Juvenile green iguanas for sale at Repticon Trading Convention 2018 in Palm Springs, Florida
Photo by Adam Toomes

Unsustainable trade of species is a major pathway for the introduction of invasive alien species at distant localities and at higher frequencies. It is also a major driver of over-exploitation of wild native populations. In a new study, published in the peer-reviewed open-access scholarly journal Neobiota, scientists estimated the desire of Australians to own non-native and/or illegal alien pets and the major trends in this practice. In addition, the team suggests ways to improve biosecurity awareness in the country.

Over the last two decades, Australia has been experiencing an increased amount of non-native incursions from species prominent in the international pet trade, such as rose-ringed parakeets, corn snakes and red-eared sliders. On many occasions, these animals are smuggled into the country only to escape or be released in the wild.

In general, the Australian regulations on international pet trade are highly stringent, in order to minimise biosecurity and conservation risks. Some highly-desirable species represent an ongoing conservation threat and biosecurity risk via the pet-release invasion pathway. However, lack of consistent surveillance of alien pets held, legally or otherwise, in Australia remains the main challenge. While there are species which are not allowed to be imported, they are legal for domestic trade within the country. Pet keepers have the capacity to legally or illegally acquire desired pets if they are not accessible through importation, and the number of such traders is unquantified.

Since keeping most of the alien pets in Australia is either illegal or not properly regulated, it is really difficult to quantify and assess the public demand for alien wildlife.

A juvenile ball python for sale at Repticon Trading Convention 2018 in Palm Springs, Florida
Photo by Adam Toomes

“We obtained records of anonymous public enquiries to the Australian Commonwealth Department of Agriculture, Water and the Environment relating to the legality of importation of various alien taxa. We aimed to investigate whether species desired in Australia were biased towards being threatened by extinction, as indicated by broader research on pet demand or towards being invasive species elsewhere, which would indicate trade-related biosecurity risks”,
shares the lead author Mr. Adam Toomes from the University of Adelaide.

According to the research team’s analysis, pets desired by Australians are significantly biased towards threatened species, invasive species and species prominent in the U.S. pet trade.

“This novel finding is of great concern for biosecurity agencies because it suggests that a filtering process is occurring where illegally smuggled animals may already be “pre-selected” to have the characteristics that are correlated with invasive species,”
warns Mr. Adam Toomes.

However, the bias towards species already traded within the U.S. suggests that there is potential to use this as a means of predicting future Australian desire, as well as the acquisition of pets driven by desire. Future research from the Invasion Science & Wildlife Ecology Group at The University of Adelaide will investigate whether Australian seizures of illegal pets can be predicted using U.S. trade data.

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Original source:

Toomes A, Stringham OC, Mitchell L, Ross JV, Cassey P (2020) Australia’s wish list of exotic pets: biosecurity and conservation implications of desired alien and illegal pet species. NeoBiota 60: 43-59. https://doi.org/10.3897/neobiota.60.51431

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Tiger geckos in Vietnam could be the next species sold into extinction, shows a new survey

The endemic reptiles are already proposed to be listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora

While proper information about the conservation status of tiger gecko species is largely missing, these Asian lizards are already particularly vulnerable to extinction, as most of them have extremely restricted distribution. Furthermore, they have been facing severe declines over the last two decades, mostly due to overcollection for the international exotic pet market. Such is the case of the Cat Ba Tiger Gecko, whose tiny populations can only be found on Cat Ba Island and a few islands in the Ha Long Bay (Vietnam).

In their study, a Vietnamese-German research team, led by PhD candidate Hai Ngoc Ngo of the Vietnam National Museum of Nature in Hanoi, provide an overview of the evidence for domestic and international trade in tiger gecko species and update the information about the abundance and threats impacting the subpopulations of the Vietnamese Cat Ba Tiger Gecko in Ha Long Bay.

By presenting both direct and online observations, interviews and existing knowledge, the scientists point out that strict conservation measures and regulations are urgently needed for the protection and monitoring of all tiger geckos. The research article is published in the open-access journal Nature Conservation.

*Cat Ba tiger gecko (Goniurosaurus catbaensis) in its natural habitat. Photo by Hai Ngoc Ngo.*

Tiger geckos are a genus (Goniurosaurus) of 19 species native to Vietnam, China and Japan. Many of them can only be found within a single locality, mountain range or archipelago. They live in small, disjunct populations, where the population from Ha Long Bay is estimated at about 120 individuals. Due to demands in the international pet trade in the last two decades, as well as habitat destruction, some species are already considered extinct at the localities where they had originally been discovered.

However, it was not until very recently that some species of these geckos received attention from the regulatory institutions in their home countries, leading to the prohibition of their collection without a permit. Only eight tiger geckos have so far had their species conservation status assessed for the IUCN Red List. Not surprisingly, all of them were classified as either Vulnerable, Endangered or Critically Endangered. Nevertheless, none is currently listed by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which could be the only efficient and reliable method to monitor, regulate and police the trade of the species on a global scale.

“Tiger geckos are neither sufficiently protected by law nor part of conservation programmes, due to the lack of substantial knowledge on the species conservation status and probably due to the general lack of public as well as political interest in biodiversity conservation,” they explain. “To date, exact impacts of trade on the species cannot be identified, as data of legal trade are only recorded for species listed in the CITES Appendices”.

During their survey, the researchers tracked local traders in possession of wild-caught tiger geckos representing all five Vietnamese species en route to foreign exotic pet markets, mainly in the United States, the European Union and Japan. The species were also frequently found to be sold in local pet shops in Vietnam, as well as being offered via various online platforms and social media networks like Facebook.

Having spoken to local dealers in Vietnam, the team found the animals were traded via long and complex chains, beginning from local villagers living within the species’ distribution range, who catch the geckos and sell them to dealers for as little as US$4 – 5 per individual. Then, a lizard either ends up at a local shop with a US$7 – 25 price tag or is either transported by boat or by train to Thailand or Indonesia, from where it is flown to the major overseas markets and sold for anywhere between US$100 and 2,000, depending on its rarity. However, many of these delicate wild animals do not arrive alive at their final destination, as their travels include lengthy trips in overfilled boxes under poor conditions with no food and water.

Indeed, although the researchers reported a large quantity of tiger geckos labelled as captive-bred in Europe, it turns out that their availability is far from enough to meet the current demands.

In conclusion, the team provides a list of several recommendations intended to improve the conservation of the Asian geckos: (1) inclusion of all tiger geckos in the Appendices of CITES; (2) assessment of each species for the IUCN Red List; (3) concealment of any currently unknown localities; and (4) improvement/establishment of coordinated ex-situ breeding programmes for all species.

*Signboard handed over to the Ha Long Bay Management Department to point to the threats and conservation need of the Cat Ba tiger gecko in English and Vietnamese languages.*

The inclusion of all tiger gecko species from China and Vietnam in CITES Appendix II was recently proposed jointly by the European Union, China and Vietnam and is to be decided upon at the Conference of the parties (CoP18) in May-June 2019, held in Sri Lanka.

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Original source:

Ngo HN, Nguyen TQ, Phan TQ, van Schingen M, Ziegler T (2019) A case study on trade in threatened Tiger Geckos (Goniurosaurus) in Vietnam including updated information on the abundance of the Endangered G. catbaensis. Nature Conservation 33: 1-19. https://doi.org/10.3897/natureconservation.32.33590