Introduction Of Non-native Fish Research Articles

Intraspecific variation in the functional responses of an invasive tropical freshwater fish under increasing temperature regimes

Global warming and the introduction of non-native fish represent major threats to freshwater biodiversity worldwide, but their effects have usually been investigated separately. Since most fish are ectotherms, their metabolism and feeding behaviour are highly influenced by temperature. Increasing water temperatures may thus exacerbate the impact of non-native fish, particularly those adapted to warmer conditions, on prey populations. Increasing temperature can also result in divergences between the impacts of females and males, especially in sexually dimorphic species.The globally invasive tropical guppy Poecilia reticulata Peters, a popular aquarium fish also used for control of mosquito-borne diseases and as a model species in ecological and evolutionary studies, exhibits strong sexual dimorphism and larvivory. This laboratory study examined prey consumption and prey size selection by guppies fed with chironomid larvae under varying temperature conditions. The effect of sex, pregnancy and prey body size on the guppy’s predatory response was also assessed by comparing Functional Responses.The results highlighted four key points: (1) increased temperature led to increased prey consumption in both females and males by decreasing handling time; (2) prey consumption was disproportionately higher in females than males, regardless of temperature; (3) temperature influenced females’ prey size selection; and (4) pregnancy reduced prey handling time among females.These findings show that temperature and intraspecific differences influence the feeding response of invasive fish, and they should both be taken into account when investigating and predicting the ecological impact of invasive species on invaded food webs.

Prioritising non-native fish species for management actions in three Polish rivers using the newly developed tool-dispersal-origin-status-impact scheme.

Biological invasions are a major threat to global biodiversity, with freshwater ecosystems being among the most susceptible to the successful establishment of non-native species and their respective potential impacts. In Poland, the introduction and spreading of non-native fish has led to biodiversity loss and ecosystem homogenisation. Our study applies the Dispersal-Origin-Status-Impact (DOSI) assessment scheme, which is a population-level specific assessment that integrates multiple factors, including dispersal mechanisms, origin, status, and impacts, providing a nuanced framework for assessing invasion risks at local and regional levels. We used this tool to evaluate the risks associated with non-native fish species across three major Polish rivers (Pilica, Bzura, and Skrwa Prawa) and to prioritise them for management actions. Using DOSI, we assessed eight non-native species identified in the three studied rivers: seven in both Pilica and Bzura and four in Skrwa Prawa. The DOSI assessment scheme identified high variability in the ecological impacts and management priorities among the identified non-native species. Notably, species such as the Ponto-Caspian gobies exhibited higher risk levels due to their rapid spread and considerable ecological effects, contrasting with other species that demonstrated lower impact levels and, hence, received a lower priority for intervention. The adoption of the DOSI scheme in three major rivers in Poland has provided valuable insights into the complexities of managing biological invasions, suggesting that localised, detailed assessments are crucial for effective conservation strategies and highlighting the importance of managing non-native populations locally.

Phenotypic and Transcriptomic Analysis Revealed a Lack of Risk Perception by Native Tadpoles Toward Novel Non-Native Fish.

The introduction of alien species poses a serious threat to native biodiversity, and mountain lake systems in the southwest of China are particularly vulnerable to the introduction of non-native fish. The prey naivety hypothesis states that native species may not be able to recognize novel introduced species due to a lack of common evolutionary background and therefore become easy targets, so the impacts of non-native fish on mountain endemic amphibians need to be urgently assessed. In an ex-situ experiment, we exposed the tadpoles of the Chaochiao Brown Frog (Rana chaochiaoensis), endemic to western China, to kairomones of both native and translocated fish species, and their phenotypic and genetic response patterns were compared. The results revealed significant phenotypic plasticity responses in total length (TOL), tail length (TL), and tail muscle width (TW) of tadpoles induced by native fish kairomone, while tadpoles exposed to translocated fish kairomone exhibited weaker phenotypic changes. At the transcriptional level, the number of differently expressed genes (DEGs) in the native fish treatment was 3.1-fold (liver) and 52.6-fold (tail muscle) higher than in the translocated fish treatment, respectively. There were more unique DEGs in the native fish treatment, primarily enriched in terms and pathways related to stress response, energy metabolism, and muscle development. The study revealed a lack of risk perception by native tadpoles toward novel non-native fish, providing new evidence for the prey naivety hypothesis from both phenotypic and molecular perspectives. Future conservation efforts should prioritize assessing the impacts of non-native fish on alpine and subalpine threatened and narrowly distributed amphibians. Additionally, prevention, early warning, monitoring, and removal of non-native fish should be carried out as soon as possible.

Global freshwater fish invasion linked to the presence of closely related species

In the Anthropocene, non-native freshwater fish introductions and translocations have occurred extensively worldwide. However, their global distribution patterns and the factors influencing their establishment remain poorly understood. We analyze a comprehensive database of 14953 freshwater fish species across 3119 river basins and identify global hotspots for exotic and translocated non-native fishes. We show that both types of non-native fishes are more likely to occur when closely related to native fishes. This finding is consistent across measures of phylogenetic relatedness, biogeographical realms, and highly invaded countries, even after accounting for the influence of native diversity. This contradicts Darwin’s naturalization hypothesis, suggesting that the presence of close relatives more often signifies suitable habitats than intensified competition, predicting the establishment of non-native fish species. Our study provides a comprehensive assessment of global non-native freshwater fish patterns and their phylogenetic correlates, laying the groundwork for understanding and predicting future fish invasions in freshwater ecosystems.

Parasitic Helminths and Freshwater Fish Introduction in Europe: A Systematic Review of Dynamic Interactions

The introduction of non-native freshwater fish is a primary cause of aquatic biodiversity loss at global scale. Such introductions have a severe impact on freshwater ecosystems in terms of competition, predation, habitat alteration, genetic pollution and transmission of diseases and parasites. A systematic review was conducted on the helminths parasites of freshwater fish in the context of species introduction and a total of 199 publications were retrieved between 1969 and November 2022. Several scenarios may arise when a new fish species arrive in a recipient area. Non-native fish hosts can co-introduce their parasites without transmitting them to native fish (e.g., the case of North American Centrarchidae and their Monogenea parasites). Another possible outcome is the transfer of these parasites to the native fish fauna (spillover, e.g., the cases of the Nematoda Anguillicola crassus Kuwahara, Niimi & Itagaki, 1974 and the Monogenea Gyrodactylus salaris Malmberg, 1957). Reciprocally, non-native fish hosts may acquire parasites in their new distribution range whether these parasites are native or were previously introduced (e.g., the cases of Ponto-Caspian Gobiidae and the Chinese sleeper Perccottus glenii Dybowski, 1877). Acquired parasites can then be spilled back to the native fauna. This phenomenon is of particular interest when non-native fish hosts influence the dynamics of zoonotic parasites.

Nile tilapia (Oreochromisniloticus) invasion impacts trophic position and resource use of commercially harvested piscivorous fishes in a large subtropical river

BackgroundAlthough freshwater ecosystems cover less than 1% of the earth's surface, they support extremely high levels of biodiversity and provide vital ecosystem services. However, due to the introduction of non-native fishes, aquatic ecosystem functioning has been altered, and in some cases, declined sharply. Quantifying the impacts of invasive species has proven problematic. In this study, we examined the relative trophic position of native piscivorous fishes to estimate the effects of invasive Nile tilapia on food webs in the downstream sections of an invaded large subtropical river, the Pearl River, China. Furthermore, we quantified how native piscivorous fish diets changed as the Nile tilapia invasion progressed.ResultsThe trophic position of the widely distributed and locally important economically harvested piscivorous culter fish (Culterrecurviceps), mandarinfish (Sinipercakneri), and catfish (Pelteobagrusfulvidraco) lowered significantly in the invaded Dongjiang River compared to an uninvaded reference Beijiang River. The lower trophic position of these piscivorous fishes was reflected by a major reduction in the proportion of prey fish biomass in their diets following the Nile tilapia invasion. Small fishes in the diet of culter fish from the reference river (33% small fishes, 17% zooplankton) shifted to lower trophic level zooplankton prey in the invaded river (36% zooplankton, 25% small fish), possibly due to the presence of Nile tilapia. Additionally, small fishes in the diet of mandarinfish in the reference river (46% small fishes, 11% aquatic insects) declined in the invaded river (20% aquatic insects, 30% small fishes). Similarly, the diet of catfish from the reference river shifted from fish eggs (25% fish eggs, 25% aquatic insects) to aquatic insects in the invaded river (44% aquatic insects, 5% fish eggs).ConclusionsThe results of this study contributed to a growing body of evidence, suggesting that Nile tilapia can modify trophic interactions in invaded ecosystems. It is crucial to understand the processes outlined in this study in order to better assess non-native aquatic species, conserve the stability of freshwater ecosystems, and improve current conservation strategies in reaches of the Pearl River and other similar rivers that have experienced invasions of non-native species.

Habitat complexity, connectivity, and introduced fish drive pond community structure along an urban to rural gradient.

Urbanization can influence local richness (alpha diversity) and community composition (beta diversity) in numerous ways. For instance, reduced connectivity and land cover change may lead to the loss of native specialist taxa, decreasing alpha diversity. Alternatively, if urbanization facilitates nonnative species introductions and generalist taxa, alpha diversity may remain unchanged or increase, while beta diversity could decline due to the homogenization of community structure. Wetlands and ponds provide critical ecosystem services and support diverse communities, making them important systems in which to understand the consequences of urbanization. To determine how urban development shapes pond community structure, we surveyed 68 ponds around Madison, Wisconsin, USA, which were classified as urban, greenspace, or rural based on surrounding land use. We evaluated how landscape and local pond factors were correlated with the alpha diversity of aquatic plants, macroinvertebrates, and aquatic vertebrates. We also analyzed whether surrounding land use was associated with changes in community composition and the presence of specific taxa. We found a 23% decrease in mean richness (alpha diversity) from rural to urban pond sites and a 15% decrease from rural to greenspace pond sites. Among landscape factors, adjacent developed land, mowed lawn cover, and greater distances to other waterbodies were negatively correlated with observed pond richness. Among pond level factors, habitat complexity was associated with increased richness, while nonnative fishes were associated with decreased richness. Beta diversity was relatively high for all ponds due to turnover in composition between sites. Urban ponds supported more nonnative species, lacked a subset of native species found in rural ponds, and had slightly higher beta diversity than greenspace and rural ponds. Our results suggest that integrating ponds into connected greenspaces, maintaining riparian vegetation, preventing nonnative fish introductions, and promoting habitat complexity may mitigate the negative effects of urbanization on aquatic richness. While ponds are small in size and rarely incorporated into urban conservation planning, the high beta diversity of distinct pond communities emphasizes their importance for supporting urban biodiversity.

Aquaculture sustainability: Global challenges need local actions

Aquaculture sustainability: Global challenges need local actions

MACROPARASITES OF GILA ORCUTTI AND PIMEPHALES PROMELAS (ACTINOPTERYGII: CYPRINIDAE) IN THE SANTA CLARA RIVER, VENTURA COUNTY, CALIFORNIA.

Freshwater fishes in the southwestern United States live in some of the most highly modified habitats in the country. As a result, the relatively small number of native fish species has been impacted in many ways, including the introduction of nonnative fishes and their parasites. Both Gila orcutti and Pimephales promelas have been introduced to the Santa Clara Drainage, the former is native to adjacent drainages in southern California, while the latter was introduced from the eastern United States. Two hundred and fourteen G. orcutti (arroyo chub) and 18 P. promelas (fathead minnow) were collected and necropsied in June through September 2017 and May through September 2018. Eight macroparasite taxa were collected from these fishes, including 6 native and 2 nonnative parasites. Four taxa of parasites were shared between G. orcutti and P. promelas: Schyzocotyle acheilognathi (Asian fish tapeworm), diplostomid metacercariae, larval acuariid cysts, and Lernaea cyprinacea (anchor worm). This study also reports the first host-association records of G. orcutti with Gyrodactylus sp., S. acheilognathi, diplostomid metacercariae, Rhabdochona sp., Contracaecum sp., and larval acuariid cysts in the Santa Clara River. Additionally, it provides the first host-association records of P. promelas with larval acuariid cysts in the Santa Clara River. This study identifies new host-parasite associations that may be useful for future conservation efforts.

Using metabarcoding and droplet digital PCR to investigate drivers of historical shifts in cyanobacteria from six contrasting lakes

The frequency and intensity of cyanobacterial blooms is increasing worldwide. Multiple factors are implicated, most of which are anthropogenic. New Zealand provides a useful location to study the impacts of human settlement on lake ecosystems. The first humans (Polynesians) arrived about 750 years ago. Following their settlement, there were marked landscape modifications which intensified after European settlement about 150 years ago. The aims of this study were to reconstruct cyanobacterial communities in six lakes over the last 1000 years and explore key drivers of change. Cyanobacterial environmental DNA was extracted from sediment cores and analysed using metabarcoding and droplet digital PCR. Cyanobacteria, including potentially toxic or bloom forming species, were already present in these lakes prior to human arrival, however their overall abundance was low. Total cyanobacteria abundance and richness increased in all lakes after European settlement but was very pronounced in four lakes, where bloom-forming taxa became dominant. These shifts occurred concomitant with land-use change. The catchment of one deteriorated lake is only moderately modified, thus the introduction of non-native fish is posited as the key factor driving this change. The paleolimnological approach used in this study has enabled new insights into timing and potential causes of changes in cyanobacterial communities.

Can the introduction of non-native fish induce variation in life-history traits of a native species in a neotropical lake?

Top predator fish, such as peacock bass (Cichla kelberi) and red-bellied piranha (Pygocentrus nattereri), were introduced in the lacustrine system of the Rio Doce basin and these introductions are associated with loss of aquatic biodiversity. The present work aims to investigate the life-history traits of a native species, thraira (Hoplias malabaricus), in the context of the pressures caused by the introduction of top predator fishes. Two lakes were selected in a conservation unit Doce River State Park (PERD), namely, Lake Carioca, where P. nattereri and C. kelberi were introduced, and Lake Gambazinho, where H. malabaricus occurs in the absence of introduced fish. In total, 146 specimens of H. malabaricus were caught, including 95 in Lake Gambazinho and 51 in Lake Carioca. Significant differences were found in the length–weight relationship (LWR) in the diet, the reproductive period, the vitellogenic follicle size, and the gonadosomatic index (GSI). In the lake with introduced species, thrairas showed allometric growth, a less diversified diet, longer duration of the reproductive period, and high GSI values compared with the control lake. The results indicated that the life-history traits of thrairas can be influenced by the environmental modification caused by the introduction of non-native peacock bass and red-bellied piranha.

Spatial and temporal variation of fish assemblage structure in a neotropical Mexican river

The introduction of non-native fish into the Teuchitlán River, in west-central Mexico, was suggested as a key factor behind the change in the fish assemblage, and even in the extinction of endemic species. The characterization of the fish assemblage and the relationship between fish abundance and the anthropogenic conditions were evaluatedover 2-year period. Fish assemblage structure, species replacement, and dominance were examined along a longitudinal environmental gradient. Physical and chemical parameters of the water were recorded. The relationship between fish abundance and abiotic factors was inferred from multivariate analysis. The results showed that the non-native poecilid Pseudoxiphophorus bimaculatus was dominant, and the abundance and biomass of non-native species exceeded 50%in all sites and seasons. Species diversity and native fish abundance were greater in upstream sites, which presented higher dissolved oxygen and lower nitrates. The native ichthyofauna of the Teuchitlán River has been replaced by non-native species. This decline of the native fish species seems to be due not only to the interaction with non-native species but also to the multiple human impacts on the lotic system.

Differential use of artificial habitats by native and non-native fish species in Neotropical reservoirs

The use of artificial habitats as tool for management and conservation of lentic freshwater ecosystems has been most studied in North America, with dominance of Centrarchidae fish. Contrary to north temperate ecosystems, Cichlidae species appear to be prevalent on artificial habitats in Neotropical reservoirs. Currently, due to the rapid expansion of non-native fish introductions globally, these two fish families are increasingly expected to coexist in the same environments. This study aimed to test experimentally the use of artificial habitats by fish in two Neotropical reservoirs between: (i) kind of habitats, (ii) Cichlidae and Centrarchidae, (iii) native and non-native species, and (iv) size classes. The results showed a higher number of individuals and species in pipes and rocks habitats. The dominance of Cichlidae over Centrarchidae in pipes, rocks and control habitats suggests a kind of partitioning between these groups. Native Cichlidae (< 80 mm) were predominant in pipes whereas native and non-native species seemed to share tree and rock habitats. Artificial habitats can potentially increase local abundance and diversity of fish species, however, it is essential to consider the species’ origin (i.e. native or non-native) associated with each kind of artificial habitat in order to prevent invasive species from benefiting of artificial structures deployment in freshwater systems.

Invasive species trait-based risk assessment for non-native freshwater fishes in a tropical city basin in Southeast Asia.

Biological invasions have created detrimental impacts in freshwater ecosystems. As non-native freshwater species include economically beneficial, but also harmful, species, trait-based risk assessments can be used to identify and prevent the import of potentially invasive species. Freshwater fishes are one of the most evaluated freshwater taxa to date. However, such assessments have mostly been done in sub-temperate to temperate regions, with a general lack of such research in the tropics. In view of this knowledge gap, this study aims to determine if a different set of traits are associated with successful establishment of non-native fishes within the tropics. In tropical Southeast Asia, Singapore represents a suitable model site to perform an invasive species trait-based risk assessment for the tropical region given its susceptibility to the introduction and establishment of non-native freshwater fishes and lack of stringent fish import regulation. A quantitative trait-based risk assessment was performed using random forest to determine the relative importance of species attributes associated with the successful establishment of introduced freshwater fishes in Singapore. Species having a match in climate, prior invasion success, lower absolute fecundity, higher trophic level, and involvement in the aquarium trade were found to have higher establishment likelihood (as opposed to native distributional range and maximum size being among the commonly identified predictors in subtropical/temperate trait-based risk assessments). To minimize invasive risk, incoming freshwater fishes could be screened in future for such traits, allowing lists of prohibited or regulated species to be updated. The findings could also potentially benefit the development of invasive species action plans and inform management decisions in the Southeast Asian region. Considering a geographical bias in terms of having relatively less documentation of biological invasions in the tropics, particularly Asia, this study highlights the need to perform more of such risk assessments in other parts of the tropics.

Non‐native freshwater fish species in the Yellow River Basin: origin, distribution and potential risk

Invasions of non-native fishes are recognized as a serious threat to freshwater biodiversity across the globe. Being the China’s second-largest river, the Yellow River has experienced severe invasion pressure of non-native fishes during recent decades. However, much less is known about species composition and distribution of non-native fishes in this river basin. Here, we investigated and summarized the literatures about non-native freshwater fish in the Yellow River Basin (YRB), to examine their taxonomic diversity, geographical origin, longitudinal distribution and potential risk. We found that 40 non-native fish species, belonging to 9 orders, 18 families and 35 genera, have invaded the YRB. Of which 19 exotic species came from other regions, while 21 translocated species were introduced into the upstream from midstream and downstream of the YRB. The aquaculture was the main vectors responsible for non-native fish introductions. An average of 8.24 non-native fish species was introduced and established per sub-region, accounting for 25.5 % of total fish species. The percentage of non-native species showed a significant unimodal model against average elevation, with the highest values (ca. 70 %) in upstream mainstream reaches and tributaries. Non-native species from historically absent or species-poor orders (Salmoniformes, Osmeriformes and Perciformes) were the most successful invaders. Furthermore, the species composition of non-native fishes changed markedly along the longitudinal gradient (i.e., from source region to downstream). The negative impacts of non-native fish introductions to native fish species, e.g., competition for resource, predation and hybridization were emerged in many introduce regions and could get worse in the future due to global warming and human activities. This study can help improve the management of non-native fish introductions and biodiversity conservation of native and endemic fish species in the YRB.

Opsanus beta (Goode &amp; Bean, 1880) (Acanthopterygii: Batrachoididae), a non-indigenous toadfish in Sepetiba Bay, south-eastern Brazil

AbstractThe introduction of non-native predator fish is thought to have important negative effects on native prey populations. Opsanus beta is a non-native toadfish that was originally described in the Gulf of Mexico, between the west coast of Florida and Belize. In the present study, we describe, for the first time, the occurrence of O. beta in Sepetiba Bay (22°55′S), south-eastern Brazil, probably brought into the bay through ships' ballast water. Thirteen specimens were recorded in this area near to Sepetiba Port. Similarly, three other records of this species in the Brazilian coast were also reported near to port areas at Rio de Janeiro (22°49′S), Santos (23°59′S) and Paranaguá (25°33′S) ports. To confirm the species identity, we employed DNA barcoding and compared our samples with sequences deposited on public databases, which indicated that our samples are highly similar (&gt;99.9% of genetic similarity) to O. beta samples collected near its type locality. Several individuals were found in the capable spawning phase, according to histological analysis of the reproductive cell stages. The environmental plasticity of this species and the favourable local environmental conditions probably enabled the establishment of O. beta in this region. This raises concerns of potential high invasion impact due to this species' diet and reproductive capacity.

Biotic differentiation in headwater creeks after the massive introduction of non-native freshwater aquarium fish in the Paraíba do Sul River basin, Brazil

Abstract This study evaluated fish beta diversity in six headwater creeks located in the area affected by the largest ornamental aquaculture center implemented in the Minas Gerais State, southeastern Brazil. We sampled fish assemblages in 2017 and 2018 to investigate changes in assemblage structure (species richness and beta diversity), comparing these data with the historic species pool. We recorded 60 fish species, of which 16 were native and 44 non-native with 19 translocated, and 25 exotic. The exotics Poecilia reticulata, Xiphophorus maculatus, X. variatus, Danio rerio, and Misgurnus anguillicaudatus were the most widely distributed in the headwater creeks. The Contamination Index showed that most creeks had high proportional contamination by exotic species (above 60%). Beta diversity increased from historical to contemporary periods in all creeks due to the introduction and differential colonization pressure of several non-native translocated and exotic species, indicating biotic differentiation. Temperature and number of ponds were the main preditors of change in beta diversity in the headwater creeks during the contemporary period. In summary, we observed that invaders have induced substantial changes to fish communities under influence of environmental filters. Our results support the hipothesis that aquaculture is a main driver of fish non-native fish introduction and native biodiversity loss in the Neotropics.

Aquarium trade and fish farms as a source of non-native freshwater fish introductions in French Guiana

Rivers of French Guiana are still little invaded by non-native fish, but several fish introductions were recently recorded through the development of aquarium fish trade and fish farms. Here we report records of 11 non-native fish species. Among them, four (Cichla monoculus,Heros efasciatus,Mesonauta guyanaeandPoecilia reticulata) are established and one of them (Heros efasciatus) is rapidly increasing its spatial range. Two species (Hyphessobrycon equesandPterophyllum scalare) were not retrieved in recent records and are probably extinct from French Guiana. The establishment status of the five other species (Arapaima gigas,Colossoma macropomum,Cyprinus carpio,Oreochromis mossambicusandOsteoglossum bicirrhosum) is uncertain and only a few specimens were observed in the wild. Nevertheless, these species, intensively reared in nearby countries, belong to highly invasive species able to cause detrimental impacts on recipient ecosystems. Those first occurrences of invasive fish species in French Guiana should therefore act as an early warning for both researchers and environmental managers.

A new wave of marine fish invasions through the Panama and Suez canals.

Recent engineered expansions of the Panama and Suez canals have accelerated the introduction of non-native marine fishes and other organisms between their adjacent waters. Measures to prevent further invasions through canals should be incorporated into global shipping policies, as well as through local efforts.

Modeling trophic interactions and impacts of introduced icefish (Neosalanx taihuensis Chen) in three large reservoirs in the Yangtze River basin, China

Non-native fish introductions may damage aquatic ecosystems. To assess the ecological impacts of the introduced icefish (Neosalanx taihuensis Chen), three reservoirs in a cascade, including the Shuibuya Reservoir (SBYR), which is devoid of icefish, and the Geheyan Reservoir (GHYR) and the Gaobazhou Reservoir (GBZR), which have large and small icefish populations, respectively, were selected for this study. Three mass-balance trophic models were established using the Ecopath approach. The results indicated that (1) the three ecosystems tended to depend more on the grazing food chain, possibly because the dominant fish species in three reservoirs were mainly filter feeders or planktivores; (2) the large icefish population in the GHYR decreased the overall energy transfer efficiency; (3) the ecosystem indices suggested that the GHYR ecosystem appeared to be a moderately mature system with a simple and vulnerable food web structure, and the lack of complexity was largely attributed to the large population of introduced icefish; and (4) the “mixed trophic impacts (MTI)” and niche overlap analysis indicated that the ecological impacts of icefish mainly came from predation and interspecific competition. This study demonstrates the consequence of icefish introduction to aquatic ecosystems and suggests that appropriate control of exotic fish is worth considering.