Invasive gibel carp (Carassius gibelio) outperforms threatened native crucian carp (Carassius carassius) in growth rate and effectiveness of resource use: Field and experimental evidence

Abstract

1. Invasive alien species pose a serious threat to biodiversity. They frequently compete with native species for resources, resulting in the decline or extinction of the latter. 2. Native crucian carp (Carassius carassius) faces a severe decline in European waters and has become critically endangered in many European countries. Possible ecological mechanisms of the rapid decline of the crucian carp attributable to resource competition with the invasive Carassius gibelio were identified. A field study was combined with a controlled experiment to compare (i) standard lengthweight relationships and growth patterns in 12 Czech and Swedish ponds in which the species occur alone or in syntopy, and (ii) individual growth and food utilization under the same conditions. 3. The growth increment of C. gibelio was greater than that of C. carassius under the same experimental conditions (mean increase in weight: C. gibelio, 21.7%; C. carassius, 5.2%; increase in standard length: C. gibelio, 6.3%; C. carassius, 2.0%), suggesting that C. gibelio uses food resources more efficiently than C. carassius does. Moreover, larger C. carassius individuals did not grow, whereas growth of C. gibelio individuals was largely independent of standard length. 4. Field data suggested that C. gibelio grew faster and were heavier than C. carassius of the same standard length in four Czech ponds where they occurred together. Individual weight-at-length declined in C. carassius in the presence of C. gibelio, especially in more dense populations, whereas the weight-at-length of C. gibelio remained similar. 5. Taken together, these results imply that C. gibelio has better competitive abilities for food than C. carassius and provide novel support for the long-standing hypothesis that the introduction and spread of C. gibelio causes the decline of C. carassius in European waters.

Living on the edge: Reservoirs facilitate enhanced interactions among generalist and rheophilic fish species in tributaries

“…Competitive interactions among fish species may lead to habitat niche displacement or even extirpation of native species (Pfauserová et al, 2021;Tapkir et al, 2022). Strong seasonal migration patterns in generalists such as roach and bleak have been described for fragmented habitats (Slavík et al, 2009;Lothian et al, 2019;Mader et al, 2020).…”

Status and Perspectives of the Ichthyofauna of the Labudovo okno Ramsar Site: An Analysis of 14 Years of Data

“…This leads to the community of these species having a highly invasive character, and it must affect the decrease in abundance or disappearance of steno-valent species, both Potamon and Rhytron, leading to dynamic instability of the population. In such disturbed communities within ecosystems that are themselves disturbed in their abiotic component, a decline in natural production is to be expected, especially for species that are less competitive in the new habitat type [31].…”

First record of highly invasive Chinese sleeperPerccottus gleniiDybowski, 1877 (Perciformes: Odontobutidae) in the Elbe River Basin, Czechia

“…Introduced invasive alien fish species (IAS) are one of the greatest threats to freshwater diversity, affecting ecosystems through novel interactions of predation, competition, or parasite/disease transmission (Reshetnikov, 2004; Tapkir et al ., 2022). The Chinese sleeper ( Perccottus glenii Dybowski, 1877) is a significant threat to wetlands and ponds in Europe and is currently listed among the 26 priority IAS of animals in the European Union (European Commission, 2017).…”

“…Its impact on amphibians is alarming, as some species of newts (Triturus cristatus, Lissotriton vulgaris) and frogs (Rana sp., Pelophylax lessonae) have been reported to disappear from the invaded sites. In addition, their feeding niche overlaps with the European mudminnow (Umbra krameri), crucian carp (Carassius carassius) and sunbleak (Leucaspius delineatus), already threatened species with very similar preferred habitat (Glińska-Lewczuk et al, 2016;Koščo et al, 2008;Tapkir et al, 2022), resulting in interspecific competition between native species and the Chinese sleeper. Another described interaction between the Chinese sleeper and native fishes is predation on developing fish eggs and smaller size classes of fish (Reshetnikov, 2001(Reshetnikov, , 2008, which can effectively eliminate other fish species in small water bodies.…”