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First record of the non-native vermiculated sailfin catfish Pterygoplichthys disjunctivus (Weber, 1991) from Lohandra River, Eastern Nepal
Abstract
The non-native vermiculated sailfin catfish Pterygoplichthys disjunctivus (Weber, 1991) is recorded for the first time in eastern Nepal's aquatic systems. Native to South America, the first reports of P. disjunctivus in Asia were recorded in India, with subsequent reports from Bangladesh, Hongkong, Indonesia, Malaysia, Singapore, Thailand and Vietnam. Our findings mark the first known occurrence of a non-native species of sailfin catfish in Nepal. The public, policy makers, researchers, and merchants of ornamental fish all need to be informed critically about the release of non-native fish into natural water systems in light of the concerns. Non-native fish may negatively affect native fish populations if released into natural waters. Therefore, it is imperative that strict measures must be taken to prevent the intentional or unintentional escape of non-native fish into Nepal's natural water systems.
This study documents new inclusions to the ichthyofauna of Nepal, focusing on four fish species: Cirrhinus cirrhosus, Labeo boggut, Piaractus brachypomus, and Oreochromis aureus. Ichthyological surveys were conducted in the Kankai River from August 2023 to July 2024, utilizing a combination of cast nets, gill nets, and local fishing tools. Specimens were subjected to detailed morphometric and meristic analyses, and their conservation statuses were reviewed. The findings underscore the importance of ongoing field investigations and conservation efforts to protect Nepal's aquatic biodiversity, particularly in the face of increasing non-native fish species introductions.
The freshwater bodies of Nepal host a great deal of fish diversity; however, the molecular study of Nepalese fish is still in its early stages. Conservation management tactics require knowledge of the real species composition, often impeded by descriptions of intermittent species based on traditional taxonomy. Catfish, one of the most overfished taxa on the planet, are abundant and heavily exploited in the eastern region of Nepal. Hence, actual catfish diversity in this region needs to be examined using a combined morphological and molecular DNA barcoding approach. In this study, we sequenced the cytochrome oxidase subunit I (COI) gene in Nepalese fish species for the first time and used it for molecular identification. Altogether, 99 specimens representing 29 species belonging to 21 genera and 8 families were successfully barcoded. They were found to be 98.5–100% identical to the known sequences deposited in the GenBank and BOLD databases. Of these, two species, Amblyceps arunachalense and Erethistoides sicula, were recorded for the first time in Nepal. Out of 29 species, one species was found to be Endangered, one species under Vulnerable, two species under Near Threatened, one species under Data Deficient, and 24 species under Least Concern. The intraspecific genetic distances within species ranged from 0 to 5%. The highest intraspecific genetic distances (Kimura 2-parameter) were found among the individuals of two species, namely, E. sicula (4%) and Glyptothorax telchitta (5%), indicating the presence of putative (sub)species. The interspecific genetic distances among the catfishes in eastern Nepal ranged between 8.47% (between Glyptothorax trilineatus and G. cavia) and 26.38% (between Amblyceps arunachalense and Chaca chaca). The GC content at the 1st, 2nd, and 3rd positions of the codons was found to be 42.4%, 49.3%, and 43.8%, respectively. These findings will support future initiatives for fish resource inventory, monitoring, and management. It is also an important input to the DNA barcode library of catfish in the eastern region of Nepal.
Non-native fishes are widespread in Hong Kong and many are likely to be established. Extensive field
surveys, literature reviews, and citizen science data were used to determine the diversity, geographic distribution,
potential introduction sources, and known impacts of non-native freshwater fishes in Hong Kong. In total, 95
species, including five putative hybrids, were recorded. In comparison, there are 65 species of native freshwater
fishes. The majority (62 species) of non-native fishes belonged to five families: Cichlidae (27 species), Cyprinidae
(15 species), Poeciliidae (eight species), Xenocyprididae (eight species), and Channidae (four species). Half of
all non-native species had at least one breeding population. Potential introduction sources were grouped broadly
into three categories: aquarium trade (associated with 62 species and two hybrids); aquaculture (20 species and
three hybrids); and water transfers from mainland China (13 species). Most of the species recorded are native to
Central and South America (27 species), East Asia (21 species), Southeast Asia (15 species), or Africa (15 species).
However, a lack of experimental or manipulative studies and a scarcity of historical data limits our understanding
of the extent of their ecological impacts. This synthesis of all currently available information could provide a
basis for future research work and policy/management strategies that seek to pre-emptively reduce the likelihood
of further species introductions to minimise potential harm to the environment.
Invasion by armoured catfishes (Loricariidae) is a threat to native fish communities of warm, freshwater habitats. Following importation as an ornamental species, the vermiculated sailfin catfish Pterygoplichthys disjunctivus, has become established in inland waters of Bangladesh. We recorded the distribution of sailfin catfish in Bangladesh. Vermiculated sailfin catfish was recorded in 17 rivers across the majority of the country, with well-established breeding populations in four localities. We measured competition between three native carps and sailfin catfish by determining growth and survival, and by carrying out gut analysis. The competition experiment was carried out using a randomised block design in earthen ponds with similar physico-chemical parameters to freshwater habitats in Bangladesh. It demonstrated that growth and survival rate of native cyprinid fishes can be adversely impacted in the presence of sailfin catfish. In high-density catfish treatments, growth of Cirrhinus cirrhosus (bottom-feeding omnivore), Labeo rohita (midwater omnivore) and Catla catla (pelagic planktivore) was reduced by 48.4%, 21.4% and 2.4% respectively, compared to controls containing the three cyprinids but no catfish. Survival of C. cirrhosus reduced to 70% in high-density catfish treatments, compared to 100% in catfish-free ponds, with lesser effects on the other species. Low- and medium-density catfish treatments generated lesser growth and survival effects. Catfish diet remained stable across density treatments, but diet of native fishes deviated increasingly from control values as catfish density increased. This study demonstrates impacts of sailfin catfish on native fish species and the increasing distribution of sailfin catfish in Bangladesh.
The present study reports a record of invasive Loricariid catfish Pterygoplichthys disjunctivus (Weber,
1991) (Siluriformes: Loricariidae) from the Bhagirathi–Hooghly system of River Ganga in West Bengal, India. The species was encountered from Farakka and Balagarh regions of Ganga, two areas with different
hydrological regimes. The average total length and total weight of the collected species was in the range of
360–450 mm and 314-545 g respectively. This exotic Species is reported to contribute about 10% of the total catch from the Balagarh area of the river stretch, while its occurrence is sparse in Farakka. The algivorous nature of feeding can pose a threat to native bottom dwelling fish due to feeding competition. As
the presence of this exotic fish in the lower parts of Ganga has been confirmed, we discuss necessary management interventions like identifying the source of its introduction in order to prevent future threats from this invasive species to native river species.
Sailfin catfish indigenous to South America are very popular ornamental fish, having previously been introduced to many regions outside their native range. Two species, namely Pterygoplichthys disjunctivus and P. pardalis, are illegal but widespread in Indonesia. They have formed self-sustaining populations, exploited for feeding of domestic animals and locally for human consumption. Also possible hybrids of the two mentioned species were recorded. The surveyed populations were considered established which perfectly fits with the climate matching analysis. Further monitoring and inspection of regions highlighted to be suitable for sailfin catfish is recommended.
A total of 123 species of non-native freshwater fish, including seven possible hybrids, are recorded from the inland waters in Singapore. The majority (84 species, 68.3%) are from four families: Cyprinidae (37 species, 30.1%), Cichlidae (30 species, 24.4%), Osphronemidae (9 species, 7.3%), and Poeciliidae (8 species, 6.5%). Of these, 42 species-mainly cichlids (12 species)-are established in Singapore. The likely pathways of introduction and pertinent conservation issues are briefly discussed. Notes on local distribution, species used for biological control, dubious records, early records of native fish species, ornamental fish trade and aquacultural species are also provided. An addendum is included for four more species.
Businesses in the pet trade collect and transport many aquatic species around the globe, and some of these individuals are released into new habitats. Some jurisdictions have introduced laws intended to regulate this trade, but these regulations have rarely had the desired effects. Laws regarding pets and the pet trade are often poorly communicated, poorly enforced, and not aligned with hobbyists’ beliefs. Consequently, some laws may increase the number of unwanted introductions instead of decreasing them. A significant change in approach is needed, involving far greater communication with scientists, administrations, politicians, the pet industry, and pet owners, promoting euthanasia of unwanted pets rather than release, and the creation and promotion “white lists” of low risk species that can be sold in the pet trade.
The American brackish-water mussel Mytella strigata is reported from Singapore for the first time. In 2016 a survey of intertidal hard structures in the Johor Straits revealed its almost ubiquitous presence in high mean densities, up to 124 ± 32 individuals 25 cm⁻² along the shoreline. Subtidal nets employed by floating fish farms were also fouled with this species. Densities exceeding 10,000 individuals 100 cm⁻² were observed, to the exclusion of its relative Perna viridis, the Asian green mussel. Size-frequency analyses of shells indicated the presence of both juveniles and adults. Juveniles have an extremely variable shell surface pigmentation. The adults, reaching 5 cm in shell length, generally have a thick dark greenish brown to almost black periostracum, but bright green and olive green individuals, some with distinctive brown streaks, have also been observed. However, sequences of the mitochondrial COI gene were consistent with mussels from Brazil, Colombia and Ecuador, where they are natively distributed, while shells were reconcilable with type material. The species may have been transported in ballast water and/or with fouling directly from its native provinces, or spread from the Philippines where there are already established populations of M. strigata, possibly since the nineteenth century.
Exotic armoured catfishes are known to be established in central and southeastern Mexico. We report the first record of the Amazon sailfin catfish, Pterygoplichthys pardalis, in Veracruz State, located on the eastern Gulf of Mexico. We captured one specimen in the Comejen River in La Florida, in March 2009, seven specimens in the Calzadas River tributary of the Coatzacoalcos River in May 2012, and three specimens in the Lagartos lagoon in Veracruz City (one in August 2012 and two in September 2013). Additional records from these regions indicate that P. pardalis is spreading in the Coatzacoalcos River basin and near Veracruz City. These records are indicative of the dispersion of this species in Mexico. Further sampling is required to assess the invasion area
Please visit the authors' website for this book: https://sites.google.com/view/fishes-of-the-world-5/welcome.
Fishes of the World, Fifth Edition is the only modern, phylogenetically based classification of the world’s fishes. The updated text offers new phylogenetic diagrams that clarify the relationships among fish groups, as well as cutting-edge global knowledge that brings this classic reference up to date. With this resource, you can classify orders, families, and genera of fishes, understand the connections among fish groups, organize fishes in their evolutionary context, and imagine new areas of research. To further assist your work, this text provides representative drawings, many of them new, for most families of fishes, allowing you to make visual connections to the information as you read. It also contains many references to the classical as well as the most up-to-date literature on fish relationships, based on both morphology and molecular biology.
The study of fishes is one that certainly requires dedication—and access to reliable, accurate information. With more than 30,000 known species of sharks, rays, and bony fishes, both lobe-finned and ray-finned, you will need to master your area of study with the assistance of the best reference materials available. This text will help you bring your knowledge of fishes to the next level.
- Explore the anatomical characteristics, distribution, common and scientific names, and phylogenetic relationships of fishes
- Access biological and anatomical information on more than 515 families of living fishes
- Better appreciate the complexities and controversies behind the modern view of fish relationships
- Refer to an extensive bibliography, which points you in the direction of additional, valuable, and up-to-date information, much of it published within the last few years.
711 pages, Index, Bibliography
We report on the occurrence of South American suckermouth armored catfishes (Loricariidae) in the Suwannee River basin, southeastern USA. Over the past few years (2009-2012), loricariid catfishes have been observed at various sites in the Santa Fe River drainage, a major tributary of the Suwannee in the state of Florida. Similar to other introduced populations of Pterygoplichthys, there is high likelihood of hybridization. To date, we have captured nine specimens (270-585 mm, standard length) in the Santa Fe River drainage. One specimen taken from Poe Spring best agrees with Pterygoplichthys gibbiceps (Kner, 1854) or may be a hybrid with either P. pardalis or P. disjunctivus. The other specimens were taken from several sites in the drainage and include seven that best agree with Pterygoplichthys disjunctivus (Weber, 1991); and one a possible P. disjunctivus × P. pardalis hybrid. We observed additional individuals, either these or similar appearing loricariids, in Hornsby and Poe springs and at various sites upstream and downstream of the long (> 4 km) subterranean portion of the Santa Fe River. These specimens represent the first confirmed records of Pterygoplichthys in the Suwannee River basin. The P. gibbiceps specimen represents the first documented record of an adult or near adult of this species in open waters of North America. Pterygoplichthys disjunctivus or its hybrids (perhaps hybrid swarms) are already abundant and widespread in other parts of peninsular Florida, but the Santa Fe River represents a northern extension of the catfish in the state. Pterygoplichthys are still relatively uncommon in the Santa Fe drainage and successful reproduction not yet documented. However, in May 2012 we captured five adult catfish (two mature or maturing males and three gravid females) from a single riverine swallet pool. One male was stationed at a nest burrow (no eggs present). To survive the occasional harsh Florida winters, these South American catfish apparently use artesian springs as thermal refugia. In the Santa Fe River, eradication might be possible during cold periods when catfish congregate in spring habitats. However, should Pterygoplichthys increase in number and disperse more widely, the opportunity to eliminate them from the drainage will pass.
We have recorded 54 species of non-native or alien freshwater ¯shes from 14 of the 15 reservoirs in Singapore. 31 of these species are established and breeding in the reservoirs. Three species (Mystus wol±i, Amphilophus citrinellum, and Satanoperca jurupari) represent new alien records for Singapore.
Trade of ornamental aquatic species is a multi-billion dollar industry responsible for the introduction of myriad fishes into novel ecosystems. Although aquarium invaders have the potential to alter ecosystem function, regulation of the trade is minimal and little is known about the ecosystem-level consequences of invasion for all but a small number of aquarium species. Here, we demonstrate how ecological stoichiometry can be used as a framework to identify aquarium invaders with the potential to modify ecosystem processes. We show that explosive growth of an introduced population of stoichiometrically unique, phosphorus (P)-rich catfish in a river in southern Mexico significantly transformed stream nutrient dynamics by altering nutrient storage and remineralization rates. Notably, changes varied between elements; the P-rich fish acted as net sinks of P and net remineralizers of nitrogen. Results from this study suggest species-specific stoichiometry may be insightful for understanding how invasive species modify nutrient dynamics when their population densities and elemental composition differ substantially from native organisms. Risk analysis for potential aquarium imports should consider species traits such as body stoichiometry, which may increase the likelihood that an invasion will alter the structure and function of ecosystems.
Pterygoplichthys punctatus and P. weberi, new species, are unique among hypostomines in having a medially divided buccal papilla. The two species can be separated from one another by color (small spots in P. punctatus, large in P. weberi), condition of the buccal papilla (deeply divided at all ages in P. punctatus vs. shallowly divided in adults of P. weberi), condition of the lateral keel odontodes (fairly short and directed posteriorly in P. punctatus vs. large and directed almost laterally in P. weberi), and body width (SL/cleithral width 3.6-4.0 in P. punctatus vs. 3.3-3.4 in P. weberi). Pterygoplichthys punctatus is known from the rio Madeira drainage and the rio Urubu of Brazil and has published, but unconfirmed localities in the rio Purus and rio Tocantins basin, and P. weberi is known from the Río Marañon, Río Ucayali, and upper Río Amazonas drainages of Colombia, Ecuador, and Peru. Pterygoplichthys punctatus e P. weberi, espécie nova, são únicos entre os hipostomíneos por possuirem uma papila bucal dividida medialmente. As duas espécies podem ser separadas entre si pela coloração (pequenos pontos em P. punctatus, pontos grandes em P. weberi), condição da papila bucal (profundamente dividida em jovens e adultos de P. punctatus vs. dividida superficialmente em adultos de P. weberi), condição da quilha de odontódios laterais (pequena e dirigida posteriormente em P. punctatus vs. grande e dirigida quase lateralmente em P. weberi), e largura do corpo (comprimento padrão/largura no cleitro 3.6-4.0 em P. punctatus vs. 3.3-3.4 em P. weberi). Pterygoplichthys punctatus é conhecida da drenagem do rio Madeira e do rio Urubu no Brasil and tem sido citada, porém sem confirmação, para localidades nas bacias dos rio Purus e Tocantins, e P. weberi é conhecida do río Marañon, río Ucayali, e drenagens do alto río Amazonas na Colômbia, Ecuador e Peru.
Non-native populations of the Neotropical family Loricariidae, the suckermouth armored catfishes, have been introduced and become established in many warm-climate regions of the world, including parts of the United States (e.g., Florida and Texas). In Florida, the most common loricariid catfishes are members of the genus Pterygoplichthys. Over the past 20 years these catfishes have invaded most inland drainages in the central and southern parts of the Florida peninsula. In certain rivers, canals, and lakes, they are widespread and abundant, accounting for a large proportion of the total fish biomass. Adult Pterygoplichthys attain sizes well over 40 cm long. In both their native and introduced ranges, Pterygoplichthys and certain other loricariid catfishes excavate and maintain burrows in shoreline slopes for use as spawning and nesting sites. The burrows are reportedly excavated and maintained by adult males. In larger reaches of some waterways, burrows created by Pterygoplichthys number in the hundreds or even thousands. The burrows are thought to cause or exacerbate bank erosion. However, there are no quantitative data available to adequately evaluate possible associations between presence and abundance of burrows and bank instability. The goal of the present study was to obtain baseline information on the burrows of Pterygoplichthys in Florida and to provide a preliminary assessment of shoreline conditions, including factors associated with bank stability and erosion. Specific objectives: 1) survey portions of selected rivers and canals in peninsular Florida to determine the number and location of loricariid catfish nest burrows; 2) measure and characterize burrow structures and surrounding habitats; 3) identify shoreline features correlated with the presence of burrows; and 4) categorize bank condition and erosion.
Native to South and Central America, many of the 700 species
of suckermouth armored catfishes (Loricariidae, Siluriformes) are popular with aquarium hobbyists as algae-controlling ornamental fishes and are therefore bred, shipped and sold around the world. They are characterized by bony plates covering the body, a pair of subterminal barbels, sucking lips, usually a spine in front of the adipose fin, and a flat-bottom body shape (Page and Burr, 1991), and are naturally occurring in a variety of freshwater habitats from sea level to 3000 m, often surviving in conditions that exclude other fishes. Members
of the genus Pterygoplichthys differ from most other
loricariids by having a large dorsal fin with 10 or more dorsal fin rays, which gives them their common name �sailfin catfish (Nico and Martin, 2001; Nelson et al., 2004; Page and Robins, 2006). Three species of Pterygoplichthys (Pterygoplichthys multiradiatus, Pterygoplichthys pardalis, and Pterygoplichthys disjunctivus) are closely related in that they lack an elevated supraoccipital process and have the supraoccipital bone posteriorly bordered by three scutes. Among these three species only P. multiradiatus (Hancock, 1898) has a pattern of uncoalesced dark spots on a light background (Page and Robins, 2006)
Globally, ornamental aquaculture is a multi-million-dollar industry and popular hobby. There are circa 6700 fish taxa being exploited and traded. Various species are traded under commercial names or codes such as certain armoured catfish of families Callichthyidae (C and CW codes or numbers) and Loricariidae (L and LDA codes). Many of these species are imported, reared and multiplied in captivity without their species identification. Here we present a detailed survey of this group of armoured catfish with a special focus on pairing of commercial codes with scientific names. In this context, both species with valid names and scientifically undescribed taxa contributed significantly to the total number of ornamental fish species by circa 25%. In total, 176 species of loricariids and 47 species of small callichthyids were paired with codes used in ornamental aquaculture. The total number of loricariids introduced as ornamentals was estimated to be more than 1000 taxa while more than 500 in small callichthyids. We recommend present findings to all stakeholders and especially taxonomists, conservationists and wildlife managers who are focused on this group of Neotropical fishes. Moreover, formal descriptions of unidentified taxa are required for feasible future monitoring and appropriate management measures of wild populations.
As humans move species around the globe, biotic homogenization decreases diversity. It is therefore crucial to understand factors influencing invasion success at a global scale. I analyzed factors predicting establishment of freshwater fishes transferred internationally, based on 1424 cases of first introductions from one country to another as reported in FishBase, an encyclopedic database of finfish biology. I used multiple logistic regression to explore four classes of predictor variables: species traits, environmental traits, match between species and environment, and propagule pressure. The best regression model, selected by Akaike's information criterion, included four factors that explained variation in establishment of 789 cases for which complete information was available. Establishment was higher for fishes in families with small body size and for omnivores. Establishment rose with endemism of the recipient country's fish fauna. Species were more likely to establish when humans intended their establishment (384/506 = 76%) rather than when fish were cultivated or used with no explicit desire for naturalization (524/918 = 57%). Three factors proved unrelated to establishment: latitudinal difference between countries of origin and introduction, native species richness of the recipient country (adjusted for area), and date of first introduction. Classification-tree analysis correctly classified (success vs. failure) 60% of 789 cases, based on the same predictor variables as in multiple logistic regression. My significant results reinforce current ideas that invasion risk is high for rapidly reproducing, generalist species introduced into isolated environments. The success of intentional introductions implies that higher propagule pressure generates riskier invasions. Both models were tested by applying them to 445 cases not used for model development. With the regression model, invasion fate was correctly predicted for low-risk (only 40% established) and high-risk (90% established) introductions. With the classification tree, 67% were correctly classified. These analyses could be used to guide quantitative risk assessment of future international transfers of freshwater fishes. The overall high rate of establishment (64%) and strong influence of propagule pressure, however, suggest that few planned introductions of freshwater fishes have low establishment risk.Resumen: Conforme los humanos se mueven alrededor del planeta, la homogeneización biótica disminuye la biodiversidad. Por lo tanto es crucial entender los factores que influyen en el éxito de invasiones a una escala global. Analicé los factores que predicen el establecimiento de peces dulceacuícolas transferidos internacionalmente, con base en 1424 casos de primeras introducciones de un país a otro registrados en FishBase, una base de datos enciclopédica de biología de peces. Utilicé regresión logística múltiple para explorar cuatro casos de variables predictoras: características de especies, características ambientales, correspondencia entre especies y ambiente y presión de propágulos. El mejor modelo de regresión, seleccionado con el criterio de información de Akaike, incluyó cuatro factores que explicaron la variación en el establecimiento de 789 casos de los que se disponía de información completa. El establecimiento fue mayor para familias de peces con tamaño corporal pequeño y para omnívoros. El establecimiento incrementó con el endemismo de la ictiofauna del país recipiente. Las especies tenían mayor probabilidad de establecimiento cuando los humanos tenían la intención de hacerlo (384/506 = 76%) que cuando los peces eran cultivados o utilizados sin el deseo explícito de naturalización (524/918 = 57%). Tres factores no tuvieron relación con el establecimiento: diferencia latitudinal entre países de origen y de introducción, riqueza de especies nativas del país recipiente (ajustada para superficie) y fecha de primera introducción. El análisis de árboles de clasificación clasificó correctamente (éxito vs. fracaso) a 60% de 789 casos, con base en las mismas variables predictoras usadas para la regresión logística múltiple. Mis resultados significativos refuerzan la idea actual de que el riesgo de invasión es alto para especies generalistas, de reproducción acelerada introducidas en ambientes aislados. El éxito de introducciones intencionales implica que la mayor presión de propágulos genera invasiones más riesgosas. Ambos modelos fueron probados al aplicarlos a 445 casos no utilizados para el desarrollo del modelo. Con el modelo de regresión, el destino de la invasión fue predicho correctamente para introducciones de bajo riesgo (establecimiento de sólo 40%) y de alto riesgo (establecimiento de 90%). Con el árbol de clasificación, 67% fue clasificado correctamente. Estos análisis pudieran ser utilizados para guiar la evaluación cuantitativa del riesgo de futuras transferencias internacionales de peces dulceacuícolas. Sin embargo, la alta tasa general de establecimiento (64%) y la fuerte influencia de la presión de propágulos sugieren que pocas introducciones de peces dulceacuícolas planeadas tienen bajo riesgo de establecimiento.
Révision du genre Pterygoplichthys sensu lato (Pisces, Siluriformes, Loricariidae)
- C Weber
Weber C (1992) Révision du genre Pterygoplichthys sensu lato (Pisces, Siluriformes, Loricariidae).
Revue françaised aquariologie 19: 1-36