Exotic Fish Research Articles

FIRST RECORD OF AN EXOTIC TRICHODINID CILIOPHORAN (CILIOPHORA: TRICHODINIDAE) Trichodina modesta Lom, 1970 FROM AN INDIAN GANGETIC LEAFFISH Nandus nandus (HAMILTON, 1822)

Nandus nandus, often known as the Gangetic leaffish, is an Asian leaffish species native to South Asia and Indochina. They are commonly found in slow-moving or stagnant bodies of water such as ponds, lakes, ditches, and flooded fields. The species is also known as speckled nandus and mud perch. This species was tested for parasite infestations in various species of freshwater fish in the river Ganges. For taxonomic evaluation, parasite smears were treated with silver nitrate. Disc-shaped trichodinids were discovered with a body diameter of 28.5-31.6 µm, adhesive disc diameter of 19.3-25.5 µm, and denticulate ring diameter of 11.2-16.8 µm. The physical traits were similar to those of Trichodina modesta Lom, 1970, a species with a strong host preference for Cypriniformes. Until recently, it was only found in the Eurasian region. The current study reports a new host for T. modesta and thus the first occurrence of this species in India. The parasite may have entered the Oriental region via the exotic fish trade, specifically Cypriniformes utilized by aquarists.

The macroparasite fauna of cichlid fish from Nicaraguan lakes, a model system for understanding host\u2013parasite diversification and speciation

The Nicaraguan lakes represent an ideal continent-island-like setting to study the colonization patterns of both fish and their parasites. The dominant fish fauna are cichlids, particularly the Midas cichlid species complex Amphilophus spp., a well-studied model for recent sympatric speciation. Here, we characterized the Midas cichlid macroparasite diversity in Nicaraguan lakes. We evaluated patterns of parasite diversity across host populations. Morphological and molecular analyses were conducted, revealing a macroparasite fauna composed by 37 taxa, including platyhelminths, nematodes, copepods, branchiurans, hirudineans and oribatids. Three invasive species are reported for the first time. The Midas cichlid was infected by 22 parasite taxa, 18 shared with other cichlids. Eight taxa conformed the core parasite fauna of the Midas cichlid. The large lakes had higher parasite diversity than the smaller and isolated crater lakes, although parasite infracommunity diversity was lower. Environmental factors along with the differential distribution of intermediate hosts, the potential resistance gained by their hosts after colonization of new lakes, competitive exclusion among parasites, or the introduction of exotic fish, may determine the observed pattern of parasite heterogeneous distribution. Our study provides a ground to explore the evolutionary history of both, hosts and parasites within the context of speciation and diversification processes.

Potential risky exotic fish species, their ecological impacts and potential reasons for invasion in Korean aquatic ecosystems

Potential risky exotic fish species, their ecological impacts and potential reasons for invasion in Korean aquatic ecosystems

Immune response of Salmo salar (exotic fish) and Eleginops maclovinus (native fish) during Francisella noatunensis horizontal transference

Bacterial transmission between cultured and native fish is potentially of great epidemiological significance. We evaluated horizontal transmission of Francisella noatunensis subsp. noatunensis from Salmo salar (Ss) to Eleginops maclovinus (Em) and vice versa by conducting cohabitation experiments. We detected F. noatunensis DNA in infected fish “Trojans” (fish injected with F. noatunensis ) and cohabitants (non-injected fish in the same tank as trojans) of both species from day 1. Additionally, we detected bacterial replication from day 1 post injection (dpi) in trojan E. maclovinus and day 14 in the other experimental conditions. We also found that hematocrit values in trojan fish were significantly decreased; however, we did not detect any corresponding decrease in cohabitating fish. Furthermore, we found that transcription of genes involved in the innate and acquired immune response in trojan fish and cohabitants, such as TRL1, TRL5, TRL8, MyD88, IL-1β, IL, MHCI and MHCII, especially at 1–3 dpi, and at 7, 14, 21 and 28 dpi in several tissues, with a tissue-dependent response. Finally, we observed an increase in serum IgM Anti- F. noatunensis antibody levels from 14 dpi in trojan fish but not in cohabitating fish. Our results demonstrate that F. noatunensis can be transmitted horizontally from S. salar to E. maclovinus and vice versa. • Bacterial transmission between cultured and native fish could be of great epidemiological significance • The horizontal transmission of F . noatunensis from Salmo salar to Eleginops maclovinus (Em) and vice versa was evaluated. • The Hematocrit values in Trojan fish were significantly decreased. • The transcription of genes involved in the innate and acquired immune response in trojan fish and cohabitants were activated. • Our results demonstrate that F. noatunensis can be transmitted horizontally from S. salar to E. maclovinus and vice versa

Exotic fish and decreasing habitats vis-à-vis conservation of freshwater fish biodiversity of Bangladesh

Multiple stressors including biological invasion have long been recognised in conservation of freshwater fish biodiversity. Works in this line have, however, been still scanty in Asia and South America – the continents known for rich biodiversity. In this study, the first of its type in Bangladesh, impacts of exotic fish and declining habitats on native fishes have been investigated. Regression and correlation analyses of 16 years production data of ponds, practically the only habitat where exotic fish are cultured commonly with indigenous ones, reveals that a maximum of 25% of the abundance decrease of native fish could be due to the effects of five commonly cultured exotic fish. Rest of the decline might largely be due to shrinkage, degradation, and destruction of habitats. Inland habitats other than ponds shrink, commonly, by about 80 % during the dry season, and most rivers are heavily polluted except for the brief mid rainy season. Decline in native fish populations may result in reduced genetic diversity. Another potential danger is the probable genetic introgression from the less fit hatchery-originated fish with the wild ones. The study concludes that the native freshwater fishes are endangered by declining habitats, exotic fishes, genetic consequences of hatchery supplementation

New records of the occurrence of Megaleporinus macrocephalus () (Characiformes, Anostomidae) from the basins of the Itapecuru and Mearim rivers in Maranhão, Northeastern Brazil.

The "piaussu", Megaleporinus macrocephalus is an anostomatid fish species native to the basin of the Paraguay River, in the Pantanal biome of western Brazil. However, this species has now been recorded in a number of other drainages, including those of the upper Paraná, Uruguay, Jacuí, Doce, Mucuri, and Paraíba do Sulrivers. This study presents two new records of the occurrence of M. macrocephalus, in the basins of the Itapecuru and Mearim rivers in the state of Maranhão, in the Brazilian Northeast. The piaussu is a large-bodied fish of commercial interest that is widely raised on fish farms, and its occurrence in the Itapecuru and Mearim rivers is likely the result of individuals escaping from fish tanks when they overflow during the rainy season. Morphological analyses and sequences of the Cytochrome Oxidase Subunit I (COI) gene confirmed the taxonomic identification of the specimens as M. macrocephalus. The COI sequences were 99.66% similar to those of M. macrocephalus deposited in the BOLDSystems database. These records extend the known distribution of M. macrocephalus to the basins of the Itapecuru and Mearim rivers in the Brazilian Northeast, highlighting a new case of introduction of exotic fish species into Brazilian river basins.

Impact of alien fishes on the distribution pattern of indigenous freshwater fishes of Punjab, Pakistan.

Pakistan is the country with mega freshwater fish diversity of native and alien species. In the presence of enormous native fishes varies species of exotic fishes have been introduced into the freshwater bodies of Pakistan which are competing with native freshwater fish fauna and making them deprive of food and habitat as well. Intentional or accidental introductions of animals, plants and pathogens away from their native niche is considered as major leading problem for biodiversity of invaded habitat. Three years study (from January 2017 to December 2019) was conducted in freshwater bodies of Province Punjab, Pakistan. Study was designed to know exotic species impacts on the distribution of native species of fishes. During current survey a total of 68 (indigenous and exotic) fish species belonging to 14 families were recorded from head Qadirabad, head Baloki, Islam headworks and Rasul barrage. Statistical analysis showed that Shannon-Wiener diversity index was the highest (1.41) at both Rasul barrage and Islam headworks but, invasive species were present in very less number in these study sites i.e. Oreochromis mozambicus, O. niloticus, Hypophthalmichthys nobilis, Carassius auratus, Ctenophryngdon idella, Cyprinus carpio and H. molitrix. The diversity index showed that comparatively low diversity was present in both area head Qadirabad (1.30) and head Baloki (1.4) due to high pressure of invasive species. Direct observation of species and statistical analysis showed that aliens' species produced negative impact on the local fish fauna diversity, evenness, and numbers. It is concluded that many factors are impacts on the diversity of native fishes, but alien (invasive) species also play a major role to reduction of native species, because aliens' species produce competition for native species. So it is urgent need to analysis the aliens and native food web and roosting sites in Pakistan, in future.

Length-Weight Relationship and Condition Factor of Village Pond-Reared Exotic Fish (Cyprinus carpio Linnaeus, 1758)

Length-Weight Relationship and Condition Factor of Village Pond-Reared Exotic Fish (Cyprinus carpio Linnaeus, 1758)

Computational study of Richness and Diversity Indices of fish species in rivers and other wetland areas and fish marketplaces under Kurigram District, Banglades

The present study revealed that a total of 101 indigenous species of large fish (28 species) and Small Indigenous fish (73 species) belonging to 63 genera and 31 families were observed and identified while 17 exotic fish species were found under 5 families. Among the indigenous species, the highest number of species were found in family Cyprinidae and Bagridae with a relative diversity of 28.28% and 11.11%. In case of group species richness, highest number 27 fish species were found in catfish group followed by 12 species of carp, 8 species of each barbs and minnows, 6 species of eel fish, 8 species of loaches, 4 species of each prawn, snake-headed or airbreathing fish and glass perches, 3 species of each climbing perches and clupeid, 2 species of each goby fish, knifefish and puffer fish, and rest of the group true perch, leaf fish, halfbeak fish, Needlefish, mullet fish, anchovies and killifish has one species. Of the total species, 47 species were considered as least concerned, 10 species as vulnerable, 11 species as endangered, 11 species as critically endangered, 14 species as nearly threatened and 8 species as data deficient. Considering the seasonal variation for all selected areas simultaneously, Shannon-Weaver diversity (H) index were found ranged from 3.53 (May) to 4.37 (January) where the highest Shannon -Weaver diversity index value 4.37 were found in winter season while 3.01 in Phulkumar, 3.73 in Dudhkumar, 3.87 in Dharla, 3.67 in Tista and 3.79 in Brahmaputra were recorded separately.

Trophic Niche Overlap between Invasive and Indigenous Fish in a Northwest Reservoir of China

The Kizil reservoir in the Tarim River basin is an important habitat for the native Schizothoracinae fish (including Aspiorhynchus laticeps, Schizothorax biddulphi, Schizothorax eurystomus, Schizothorax intermedius and Schizothorax barbatus). Unfortunately, these species are threatened by many exotic fish, such as Ctenopharyngodon idellus, Silurus asotus. As an isolated habitat, the Kizil reservoir is an ideal area for studying biological invasions. However, the impact of invasive species on indigenous species in this reservoir remains unknown. In this study, the niche width and niche overlap between invasive and indigenous species in Kizil reservoir were studied based on stable isotope analysis. The results showed that niche width of two invasive species, S. asotus and C. idellus, was larger than that of native fish species, which confirmed the hypotheses that successful invaders have larger niche width. The niche overlap analysis showed that the two invasive species had high niche overlap with native fish species, which meant that there might be intensive interspecific competitions between them. The invasion of non-native species could be the main reason for the decrease of native species in the Kizil reservoir.

Evaluation of fish assemblages’ composition in the Euphrates River, southern Thi-Qar province, Iraq

Fish assemblage composition in the Euphrates River southern Thi-Qar province was assessed from January to December 2018. Various fishing methods were used to collect the samples. A total of 3010 specimens of bony fishes were caught represented 17 species, 17 genera, ten families and six orders. The species included ten native fish species and seven exotic fish species. The Abu mullet Planiliza abu was the most abundant species formed 26.21% of the total caught, blue tilapia Oreochromis aureus 19.30%, Prussian carp Carassius gibelio 17.48% and Redbelly tilapia Coptidon zillii 13. 29% of the total number of species. The dominance index (D3) value of the highest abundance represented by three fish species that preside the study area forming 62.99%, there are P. abu, O. aureus and C. gibelio. The occurrence of fish species contained seven fish species formed 92.03% of the total species caught. Seasonal fish species comprised of three fish species included 6.51% and occasional fish species contained seven species represented 1.46% of the total number of species. The diversity index values appear as poor ranged from 1.59 in December to 2.07 in April. Richness index values pointed to disturbing status, varied from 1.21 in September to 2.00 in May. Evenness index tends to be balanced, fluctuated from 0.79 in June to 0.91 in February and July. The present study verified the prevalence of the small-sized tolerance fish species represented by one native and three exotic species, with rarely or absence of the keystone native fish species of fish communities predominating the south of Iraq.

Fish Diversity and Its Threatened Status of the Dharla River in Bangladesh

Abstract Fish diversity of a riverine ecosystem became reduced due to different manmade and natural calamities. This study investigated the present fish biodiversity status of the Dharla River located (25.8103° N, 89.6487° E) in the northern part of Bangladesh from January to December 2018. In this study, the existing fish biodiversity status of the Dharla River was estimated in terms of diversity indices and threatened status (both global and local). Data was collected from the three sampling sites of the river using different fishing gears and three selected fish markets located in the Kurigram district of Bangladesh. A total of 76 fish species were identified belonging to 8 orders, 26 families and 57 genera. The Cyprinidae was the most dominant family represented by 14 species followed by the Danionidae (13 species), Bagridae (8 species) and few minor families. Apart from the indigenous species, nine exotic fish species were also recorded. The Shannon-Weaver diversity (H), Pielous evenness (e) and Margalef richness (D) indices ranged from 3.00 to 3.71, 0.62 to 0.94 and 3.94 to 7.95, respectively. Out of 76 indigenous species, 28 species (37%) were identified as threatened in Bangladesh, which included critically endangered (4), vulnerable (9) and endangered (15) species. Indiscriminate fishing through poisoning and destructive fishing gears were identified as the major threats to fish biodiversity of the Dharla River. Thus, the river serves as considerable support for threatened indigenous fishes. Therefore, necessary steps are needed to stop destructive fishing, establish permanent fish sanctuaries and proper monitoring for maintaining sustainable biodiversity in the Dharla River.

First record of exotic alligator gar, Atractosteus spatula (Actinopterygii: Lepisosteiformes: Lepisosteidae), from Ganga River system, India: A possible threat to indigenous riverine fish diversity

A new record of an exotic alligator gar, Atractosteus spatula (Lacepède, 1803), from an open wetland of the Ganga River was presented in this paper and discussed along with the environmental parameters. Entry of the exotic fish into the natural system was probably a result of uncontrolled ornamental fish trading. Considering threats of this predatory fish to become invasive and disturb riverine fish diversity, possible ways to avoid such risk have been discussed.

Market Infrastructure and Species Availability of Four Wholesale Fish Markets in Dhaka City, Bangladesh

The study was conducted on species availability and infrastructure analysis of four different wholesale fish markets in Dhaka City. Two markets were selected from Dhaka South City Corporation, Showari Ghat and Jatrabari fish market, and two from Dhaka North City Corporation, Karwan Bazar and Abdullahpur fish market. The investigation was carried out from November 2018 to October 2019. Questionnaire based survey, FGDs (Focus Group Discussion) and KIIs (Key Informant Interviews) were conducted to get quantitative and qualitative data for present study. A total number of 62 fishes and 6 crustacean species were recorded during the study period. Among all species, 39 freshwater, 10 marine and 13 exotic fishes were recorded. Infrastructure facilities were very poor for all four markets in the matter of hygiene and quality control. Fish shades were not enough, improper sanitation and drainage system indicates the possibilities of disease transmission and deteriorate fish quality. Electricity and water supplies were good but no system was present to determine the distillation of those supplied water. Thus, infrastructural condition of the markets does not support a hygienic condition for fish marketing to provide quality fish and fish byproducts. The study highlighted the need for national initiatives, awareness building, and law implementation for improving the wholesale markets infrastructure to a minimum standard so that fish trade could provide good quality to the people of Dhaka City Bangladesh J. Zool. 49 (2): 289-300, 2021

CYPRINUS CARPIO VAR. COMMUNIS, IN MIDDLE STRETCH OF RIVER GANGA AT ALLAHABAD

Cyprinus carpio, commonly known as common carp, is an exotic fish species in India. Presence of this species has been reported to reduce diversity and modify local community dynamics in freshwater systems (Minns and Cooley, 2000). They are perceived as a significant ecological pest in many countries where they have been introduced (Arlinghous and Mehner, 2003) and are generally considered ecologically most detrimental of all freshwater invasive fish species (Crivelli, 1983; Zambrano et al., 2001; Dean, 2003; Koehn, 2003). Despite all these features the common carp forms the most common fishery of the world. Today many countries have extensive and intensive farming of common carp. Common carp prefers slow and stagnant water bodies, and /or silt bottoms with shell incorporations (Balon, 1995). The present study was aimed to assess on the population structure of C. carpio in the middle stretch of the Ganga river at Allahabad.

Checklist of endemic (Adrianichthyidae, Gobiidae, Zenarchopteridae) and introduced fish in Lake Poso, Sulawesi, Indonesia

Lake Poso is one of the ancient lakes in the world. This lake is known to have high diversity of endemic fish. Several exotic fish species have been introduced to increase the fisheries production in the lake. However, it is reported that the introduced fish is one of the causes of the threat of the existence of endemic fish in this lake. This study aimed to obtain the latest information on endemic (Adrianichthyidae, Gobiidae, and Zenarchopteridae), and introduced fish in Lake Poso. The research was carried out from May to July 2019 at 17 stations on the coast and rivers of Lake Poso. Fish were collected using a seine net, tray net, and hook and line. The results showed that there were 13 species of fish belonging to eight families and 11 genera. A total of six endemic fish species were still found in this study, namely Adrianichthys oophorus, Oryzias nebulosus, O. nigrimas, O. orthognathus, Mugilogobius sarasinorum, and Nomorhamphus celebensis. Seven species of introduced fish were found, namely Anabas testudineus, Aplocheilus panchax, Channa striata, flowerhorn (Cichlasoma sp.), Melanocromis auratus, Oreochromis niloticus, and Trichopodus trichopterus. Cichlids (flowerhorn, M. auratus, and O. niloticus) have the potential to be invasive due to their adaptability and ease of reproduction in Lake Poso. Conservation of the fish endemic to Lake Poso must be a serious concern for the government, academics, and the community. Ex-situ conservation can be a strategy to conserve the endemic fish of Lake Poso through controlled captivity.

Can geometric morphometrics and traditional methods work for evaluation of body shape plasticity of exotic fishes? A case study of topmouth gudgeon, Pseudorasbora parva (Teleostei: Gobionidae)

Introduction of species outside their native distribution ranges, followed by population establishment and becoming an invasive element, has been a common task and a controversial issue in the last century. The topmouth gudgeon Pseudorasbora parva is a gobionid fish native to southeast Asia, with a high dispersion potential, which succeeded in spreading out in many countries of Eurasia and north Africa including Iran during the almost 50 years. In this study, we are addressing the following research questions: (1) how do fish morphology differ in different water bodies by applying traditional, and geometric morphometric methods? (2) does morphology of P. parva show previous molecular-phylogenetic research based on mtDNA? Results revealed that traditional morphometric characters do not demonstrate a high phenotypic variation among 20 populations of P. parva collected from nine basins/river drainages. The cluster analysis of Euclidean distances among groups of P. parva populations (nine basins/river drainages) revealed segregation of three populations (Harirood, Esfahan and Mashkid basins). Based on the genetic background and colonisation history of P. parva using the mitochondrial DNA control region (806 bp) and a cytochrome c oxidase subunit I barcode database (615 bp), presence of three matrilineal haplotypes belonging to two distinct lineages; (1) a widespread lineage with a common haplotype found throughout the country and one exclusive haplotype confined to the Mashkid basin, whose origin can be traced back to a single introduction of a small number of propagules from Japan, and (2) a Chinese lineage represented by a single haplotype found in the Shafarood River of the Caspian Sea basin but also translocated to central Iran. This genetic clustering is somehow in correspondence to the dendrogram derived from the cluster analysis of geometric-morphometrics of P. parva populations and might be due to habitat-induced or genetically induced changes (e.g., fish origin), or it may arise due to the combination of both.

Does aquaculture aggravate exotic fish invasions in the rivers of southern China?

Human-induced fish introduction in aquaculture always be considered the most important driver of biological invasions in freshwater ecosystems, yet most introduced species fail to establish though having great economic benefits. Explaining the varying success of introduced fish species is a central question both in invasion biology and aquaculture management. Southern China is a good region to test the invasion hypotheses where lots of non-native fish species were cultured and invaded. In this study, we used four human activities related to aquaculture to test their effects on the establishment of non-native fish species in the rivers of southern China. Our results showed that: open-water aquaculture significantly increased the establishment probabilities of non-native species relative to standardised aquaculture in ponds; the establishment and spread of non-native fish species in rivers had no significant correlation to their production and distribution in standardised aquaculture; non-native fish species with low economic value were more prone to escape and establishment in natural rivers, and had higher establishment probabilities in rivers due to the lower fishing pressure. These results indicate that standardised aquaculture and cultivated species with high economic value do not always result in biological invasions. To mitigate the invasion of exotic species caused by aquaculture, stricter management practices and more optimized economic assessments should be implemented for the introduction and cultivation of non-native fish species.

A comparison of passage efficiency for native and exotic fish species over an artificial baffled ramp.

This study used an experimental approach to compare the passage success of native and exotic fish species from the temperate Southern Hemisphere over an artificial baffled fish ramp designed for overcoming low-head (≤1.0m) fish migration barriers. Passage efficiency was, on average, lower for the exotic species [koi carp (Cyprinus carpio), rudd (Scardinius erythrophthalmus) and rainbow trout (Oncorhynchus mykiss)] compared to the native species [inanga (Galaxias maculatus), redfin bully (Gobiomorphus huttoni) and common bully (Gobiomorphus cotidianus)]. Nonetheless, there was considerable variation between individual species, with rainbow trout outperforming common bully and juvenile inanga, but koi carp and rudd failing to pass any of the ramps. The differences in predicted probability of passage success between the native and exotic fish species in this study were sufficient in some cases to indicate the potential for the baffled fish ramps to operate as a selective migration barrier. Nonetheless, further testing is required to validate these results across a broader range of conditions before deployment.

Exotic plus native: findings in an unscheduled fish duoculture

The development of native fish aquaculture represents an important alternative to mitigate ecological displacement generated by exotic fish. The introduction of native fish in polyculture systems with high commercial value fishes has provided a useful strategy for sustainable aquaculture development. The present study aims to provide information on tilapia, as an exotic species, and Dormitator latifrons, as a native species, in a duo culture not programmed as such. Using juveniles of Pacific fat sleeper D. latifrons leftovers from another experiment, we decide to analyze and report the biological feasibility of a duoculture system with this species and Nile tilapia (Oreochromis niloticus). Two hundred fifty organisms of each species were placed for 90 days in a concrete tank with a capacity of 50 m3 to evaluate the compatibility of these species. The biological variables measured were growth, survival, feed conversion rate, and protein efficiency. The findings suggest a good interaction between species, with adequate growths and a survival rate of 98%. No antagonistic behavior was observed during confinement, suggesting the duoculture of these species may represent a good alternative for tropical sustainable aquaculture.