Marmorkrebs in Taipei update

Last November, I reported on Marmorkrebs were found in Taipei, but they seemed to be confined to a single park pond. A brief mention in a new story suggests there is a second location that has become home to a population of Marmorkrebs. 

The firefly restoration ecological pond in Taipei’s Daan Forest Park is being invaded by an exotic species, the many-rayed sailfin sucker catfish, while Neihu District’s (內湖) Bihu Park is being invaded by the invasive marbled crayfish, causing ecological balance issues, the office said.

 

Emphasis added.

 

Marmorkrebs were previously reported in Daan Forest Park, so it is not entirely clear to me if Marmorkrebs are in two parks, or id the reporter inadvertently switched the two locations. I have updated the map of Marmorkrebs introductions with the second Taipei location, but noted the uncertainty.

 

External links

Taipei to issue fines for feeding wildlife in parks

 

Related posts

 

Marmorkrebs’ second Asian invasion

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