| Stone moroko | |
|---|---|
.jpg) | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cypriniformes |
| Suborder: | Cyprinoidei |
| Family: | Gobionidae |
| Genus: | Pseudorasbora |
| Species: | P. parva |
| Binomial name | |
| Pseudorasbora parva | |
| Synonyms[2] | |
| |
Thestone moroko (Pseudorasbora parva), also known as thetopmouth gudgeon,[1] is a species of freshwaterray-finned fish belonging to thefamilyGobionidae, the gudgeons.[2] This species is native toAsia, but has been introduced and is now considered aninvasive species inEurope andNorth America. The fish's size is rarely above 8 cm, and usually 2 to 7.5 cm (0.79 to 2.95 in) long.[3]
In Europe,P. parva has been included since 2016 on the list of Invasive Alien Species of Union concern (the Union list).[4] This implies that this species cannot be imported, bred, transported, commercialized, or intentionally released into the environment in the whole of the European Union.[5]
The fish was introduced in the 1960s into ponds inNucet,Dâmbovița County,Romania, and made its way intoDanube, then spreading throughout Europe.
These fish feed on eggs of locally valuable native fish species.
Four phylogenetic lineages ofPesudorasbora parva were identified within its native range, and three of them contributed to the dispersal within more western regions of Eurasia. One of these lineages was initially distributed in the north of China and the Far East of Russia; the second was in southern China; the third was in the Korean Peninsula and, probably, in the adjacent regions of China; and the fourth was in Taiwan. Geographical distribution ofCOI lineages suggests three donor regions of stone moroko invasions into more western regions of Eurasia: the basin of theYangtze River, the northern (Russian) part of theAmur River basin, and theSungari River basin (right tributary of the Amur in the territory of China).[6]
The species has also been recently discovered in several lakes in the UK, where it is believed to have been illegally stocked. This has called for a large scale eradication programme organised by the Environment Agency, who kill the fish off with a piscicide calledrotenone.[7]
Pseudorasbora parva poses a danger to other species such as the sunbleaks (Leucaspius delineatus). These fish are the carrier of a parasite, the protistSphaerothecum destruens,[8][9] that is not damaging to the topmouth gudgeon, but attacks other fishes like the sunbleaks, which are unable to spawn and have a higher mortality when infected.[8][10]
A 2023 study showed co-introduction of threemonogenean species,Dactylogyrus squameus,Bivaginogyrus obscurus, andGyrodactylus pseudorasborae into Europe, along with their fish host from East Asia. In addition to co-introduced parasites, the fish was infected with a local generalist, the monogeneanGyrodactylus prostae. Monogenean infections were generally lower in non-native host fish, potentially giving an advantage to this invading species.[11]
