Roje and colleagues 2021

Roje S, Richter L, Worischka S, Let M, Veselý L, Buřič M. 2021. Round goby versus marbled crayfish: Alien invasive predators and competitors. Knowledge and Management of Aquatic Ecosystems 422: 18. https://doi.org/10.1051/kmae/2021019
 

Abstract

Aquatic biodiversity is threatened by spread of invasive alien species. Round goby Neogobius melanostomus is an invasive fish in large European rivers as well as in coastal waters near their mouths and marbled crayfish Procambarus virginalis is a highly invasive crustacean. Both are small, bottom-dwelling species occupying similar habitat and shelters and utilizing similar food sources. We hypothesized that goby presents a threat to both native and non-native astacofauna in invaded ecosystems. We tested this through laboratory experiments designed to determine aggressiveness and competitiveness of goby against marbled crayfish as a model for other North American cambarid crayfish, assessing goby prey size selection and competition with marbled crayfish for space and shelter. Gobies showed high aggressiveness and dominance over the crayfish. Goby predation on juvenile crayfish was limited by mouth gape size. In goby/crayfish pairs of similar weight, gobies were more aggressive, although each affected the behavior of the other.

 

Keywords: Biological invasion • freshwater • predation • shelter competition • species interaction

 

 

Kouba and colleagues 2021

Kouba A, Lipták B, Kubec J, Bláha M, Veselý L, Haubrock PJ, Oficialdegui FJ, Niksirat H, Patoka J, Buřič M. 2021. Survival, growth, and reproduction: Comparison of marbled crayfish with four prominent crayfish invaders. Biology 10(5): 422. https://www.mdpi.com/2079-7737/10/5/422

 

Abstract

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 red swamp crayfish as well as the Australian common yabby. The marbled crayfish is among the most outstanding freshwater crayfish invaders due to its parthenogenetic reproduction combined with early maturation and high fecundity. As their introduced ranges expand, their sympatric populations become more frequent. The question of which species and under what circumstances will dominate in their introduced communities is of great interest to biodiversity conservation as it can offer valuable insights for understanding and prioritization of management efforts. In order to examine which of the aforementioned species may be more successful as an invader, we conducted a set of independent trials evaluating survival, growth, claw injury, and reproduction using single-species stocks (intraspecific interactions) and mixed stocks (interspecific interactions) of marbled crayfish vs. other crayfish invaders since the onset of exogenous feeding. In both single and mixed stocks, red swamp crayfish and yabby grew faster than marbled crayfish, while marbled crayfish were superior to both spiny-cheek and signal crayfish in terms of growth. With the exception of signal crayfish, the faster-growing species consistently reached a higher survival rate. The faster-growing species tended to negatively impair smaller counterparts by greater claw injury, delayed maturation, and reduced fecundity. Only marbled crayfish laid eggs as early as 14 weeks in this study, which is earlier than previously reported in the literature. Thus, the success of marbled crayfish among invasive crayfish is significantly driven by relatively fast growth as well as an early and frequent reproduction. These results shed light on how interactions between invasive populations can unfold when their expansion ranges overlap in the wild, thereby contributing to the knowledge base on the complex population dynamics between existing and emerging invasive species. 

Keywords: Biological invasion • pet trade • animal release • species interactions • sympatry

Zoobabies, 2021 edition

The Cincinatti Enquirer answers a question I’ve been wondering for a while. 

 

Some years ago, I noted the Cincinatti Zoo had a display of “Marbled crayfish” and listed them as Procambarus fallax. The zoo’s description mentioned nothing about asexual reproduction, so I thought they were slough crayfish from Florida or Georgia.

But a new article about the zoo says:

 

This baby marbled crayfish resembles a small lobster, but it will only grow to 2 to 3 inches long. All marbled crayfish are women. They don't need a partner to reproduce.

 

Marmorkrebs they are, then! Which makes me wonder why their reproduction wasn’t mentioned on the display.

Related posts

 

Zoo babies

 

External links

 

Up close with the Cincinnati Zoo's most adorable ambassadors

International Conference on Aquatic Invasive Species 2022

The date for the next conference on aquatic invasive species will be 18-22 April 2022 in Belgium. It will be a mix of in person and online and the focus will be on climate change. But I’m sure there will be some crayfish content!

 

It must be challenging to plan conferences, since COVID-19 is still out of control in some regions but maybe coming under control with vaccination and we really don’t know what will happen.

External links

 

22nd International Conference on Aquatic Invasive Species

Ontario seeks public comment on regulating marbled crayfish

Nation Valley News reports that Ontario is moving to the next phase of a process that could result in the regulation of Marmorkrebs in the province, along with twelve other aquatic species.

 

The first round of consultation identified “no significant concerns” of regulating Marmorkrebs.

 

A ban on Marmorkrebs in Ontario would arguably be the most significant regulatory action in North America yet implemented. Ontario is Canada’s most populous province. It’s also one of the largest single jurisdictions in terms of size in North America. Currently, Marmorkrebs are routinely available in the pet trade.

Louisiana red swamp crayfish (Procambarus clarkii) are also on the list. This crayfish would get an exception for its use as food.

Comment is open until 7 June 2021.

External links

 

Regulating 13 invasive species and watercraft as a carrier of invasive species under Ontario’s Invasive Species Act, 2015

 

Seeking information on invasive species and carriers under the Ontario Invasive Species Act, 2015 (closed)

 

Province seeks input into wild pig strategy and updates to Invasive Species Act

 

Scheers and colleagues 2021

Scheers K, Brys R, Abeel T, Halfmaerten D, Neyrinck S, Adriaens T. 2021. The invasive parthenogenetic marbled crayfish Procambarus virginalis Lyko, 2017 gets foothold in Belgium. BioInvasions Records 10(2): 326-340. https://doi.org/10.3391/bir.2021.10.2.11

 

Abstract

 

In 2020, four populations of the marbled crayfish Procambarus virginalis, which is included on the list of Invasive Alien Species of Union concern, were discovered in northern Belgium. These records represent the first established populations of this invasive parthenogenetic species in the Benelux. The marbled crayfish seems well established at all sites where it was discovered. Genetic analysis confirmed the species’ identity with the obtained COI Folmer fragments being 100 percent identical to reference sequences of P. virginalis from Germany, Italy, Sweden and the Czech Republic. We proposed a single diagnostic nucleotide for unambiguous character-based species identification between P. virginalis and P. fallax. The finding of this new species through opportunistic surveys instigated by citizen science reports indicates considerable knowledge gaps on crayfish distribution in Belgium. Considering the regulated status of most species in Belgium, we advocated the further set-up of dedicated crayfish surveillance using passive and active monitoring including environmental DNA detection.

 

Keywords: invasive species, Cambaridae, non-native species, Procambarus fallax forma virginalis

Stara and colleagues 2021

Stara A, Zuskova E, Vesely L, Kouba A, Velisek J. 2021. Single and combined effects of thiacloprid concentration, exposure duration, and water temperature on marbled crayfish Procambarus virginalis. Chemosphere 273: 128463. https://doi.org/10.1016/j.chemosphere.2020.128463

Abstract

The increasing utilization of chemicals and ongoing climate change have a negative impact on aquatic ecosystems. The present study examined combined effects of water temperature, chemical concentration, and duration of exposure to the neonicotinoid thiacloprid on marbled crayfish Procambarus virginalis. Crayfish were exposed to thiacloprid at the environmental concentration of 4.50 μg L^-1 and 10% 96LC50 to marbled crayfish, 64.64 μg L^-1, at water temperature of 17 and 23°C for 28 days followed by a 28 day depuration period. No crayfish died during the experiment. Both thiacloprid concentrations at 23°C showed a synergistic effect with temperature on the biochemical indicators in haemolymph compared to those at 17°C. Both concentrations of thiacloprid at both temperatures were associated with significant differences from thiacloprid-free controls (P < 0.01) in haemolymph glucose, ammonia, calcium, inorganic phosphate, and lactate; haemolymph enzymes aspartate aminotransferase, alanine aminotransferase, creatine kinase, and alkaline phosphatase; antioxidant biomarkers superoxide dismutase, catalase, glutathione S-transferase, and reduced glutathione in hepatopancreas, muscle, and gill, and showed lipid peroxidation in hepatopancreas and muscle. Histological analyses revealed structural changes and damage to gill and hepatopancreas of exposed crayfish.

Keywords: neonicotinoid • insecticide • non-target organism • synergism • haemolymph • antioxidants