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We assessed genetic diversities among Ichthyophthirius multifiliis (Ich) field isolates collected from farmed rainbow trout (Oncorhynchus mykiss) in Turkey. The overall prevalence of Ich was 35.3% (634/1798). Five novel Ich genotypes (ImulTR1 and ImulTR3-ImulTR6) were described based on mitochondrial cox-1 and nad1_b genes. The remaining genotype ImulTR2 was identical to the previously reported NY3 (or Ark9 and TW7) genotype from the United States and South Asia. Phylogenetic analysis indicated Turkish Ich isolates separated genetically into at least four distinct groups. Our study presents the first data on the genotypes of Ich in Turkey. We also provide evidence for the wide distribution of the NY3 genotype (or Ark9 and TW7) from the United States and South Asia to Turkey. Genetic diversities within the mitochondrial genes provided adequate resolution for describing novel genotypes and identifying the known genotype within Turkish Ich isolates. Description of the Ich genotypes allows for tracking of pathogen genotypes worldwide. Thus, we can better understand the connections between Ich outbreaks in the fisheries aquaculture., (© 2022 John Wiley & Sons Ltd.)

The ciliate Philasterides dicentrarchi has been previously identified as a new agent of scuticociliatosis in marine fish. The parasite can cause high mortalities in fish reared on farms or kept in aquariums. P. dicentrarchi is usually a free-living protozoan but can become an opportunistic histophagous parasite causing rapid lethal systemic infections in cultured fish. This review provides information about the morphology and biology of the scuticociliate P. dicentrarchi, as well as information about the pathological and immunological reactions of the host in response to the infection with the parasite. The epidemiology and the control strategies of the disease are also reviewed.

Silver pomfret Pampus argenteus is a major cultivated marine fish species with a high market value. In summer 2021, Cryptocaryon irritans, a ciliate parasite, infected the cultured silver pomfret in aquaculture ponds in Ningbo, Zhejiang Province, China. The symptoms of infected fish include white spots on the skin and fins, increased body surface mucus, loss of appetite, irritability, and shedding of scales. After collecting white spots from moribund fish, the 18S ribosomal RNA sequence of the pathogen on the fish skin was amplified by PCR; phylogenetic analysis showed that it was closely related to C. irritans strains from Ningde, Fujian, China. Four groups of silver pomfret were tested in an artificial infection experiment over the course of 72 h, consisting of 3 infected groups (1600, 4000, and 8000 theronts fish-1) and 1 healthy group. White spots were observed on the skin and fins of the infected fish, but not on their gills. Samples were taken from the gills, liver, kidney, and spleen of both infected and healthy fish and were compared to evaluate any significant histopathological differences. As the dose of infection increased, symptoms became more pronounced. At 72 h, mortality rates were 8.3, 50, and 66.7% for the 3 different concentrations, respectively. The median lethal concentration was calculated to be 366 theronts g-1 at 72 h, 298 theronts g-1 at 84 h, and 219 theronts g-1 at 96 h. This study emphasizes the importance of developing early diagnosis methods and appropriate prevention strategies to decrease the impact of C. irritans infection in the silver pomfret aquaculture industry.

During an investigation of parasitic ciliates in northern China, two Trichodina species, T. acuta Lom, 1970 and T. nigra Lom, 1960, were isolated from the freshwater fish Cyprinus carpio Linnaeus, 1758. The morphology of each species was investigated based on dry silver nitrate-stained specimens. In addition, the molecular phylogeny of each was analyzed based on small subunit ribosomal DNA (SSU rDNA) sequence data. Trichodina acuta can be distinguished from its congeners by the undefined periphery of the central circle, the distinct gap between the rays and the central circle, and the distinctly sickle-shaped blades. Trichodina nigra is a cosmopolitan ciliate and is characterized by its densely linked denticles, broad, rounded spatula-shaped blades, robust central parts, and well developed rays. Phylogenetic analyses revealed that T. acuta and T. nigra nest within different clades, supporting the assertion that the GC content of SSU rDNA sequences could reflect evolutionary relationships among Trichodina species., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Artificial breeding of small yellow croaker (Larimichthys polyactis) was recently achieved, providing a bright future for its commercial farming. In May 2019, a disease outbreak occurred among small yellow croakers in an aquaculture farm near Xiangshan Bay, charactering by white spots spotted on the surface of fish skin, gills and fins. The parasite was preliminarily identified as Cryptocaryon irritans based on morphological feature of the parasite and the symptoms on fish. However, the previously published specific primer pairs failed to confirm the existence of C. iriitans. Six nucleotides mismatches were discovered after mapping specific forward primer back to targeted gene. Therefore, an updated PCR specific primer was developed within the 9th highly variable region of 18S rRNA gene and conserved in all C. irritans sequences available in GenBank database. The specificity was verified in silico by Primer-BLAST against GenBank nucleotide. Laboratory cultured ciliates (Mesanophrys, Pseudokeronopsis and Uronema) as well as natural microbial community samples collected from sea water and river water was used as negative control to verify the specificity of the primer in situ. Besides, tank transfer method was used to evaluate the treatment of the parasite infection. By tank transfer method, 2.00 ± 0.61 out of 10 fish that already sever infected were successfully survived after 8 days treatment, meanwhile the control group died out at d 6. More loss to the treatment group during first five days was observed and may attribute to the combined effect from infection and stress the recent domesticated fish suffered during rotation. Therefore, tank transfer method was also effective to prevent small yellow croaker from further infection, however the loss of the small yellow croaker suffered from stress during rotation also needs to be carefully concerned. In conclusion, this study reported the first diagnose of C. irritans infection on small yellow croaker, provided updated specific primer to detect C. irritans infection on fish body and reported the effect of tank transfer on small yellow croaker treatment., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A disease outbreak occurred in swimming crab (Portunus trituberculatus) farmed in eastern China, with a mortality rate of more than 80%. To further investigate the characteristics and pathogenesis, we reported isolation, characterization and virulence of the causative agent of this disease from 10 sick crabs. Histopathological observation found that multiple tissues, especially haemolymph, contained lots of ciliates. The ciliate was isolated and cultured in vitro, and molecular and morphological studies were done. The results showed that SSU rDNA and LSU rDNA sequences of the ciliate were similar to Mesanophrys ciliates (>96.81%), while ITS1-5.8s-ITS2 sequence was similar to Mesanophrys pugettensis (95.37%) and identical to Orchitophrya stellarum (100%). Furthermore, the results of the morphological study confirmed that the ciliate was similar to Mesanophrys ciliates and O. stellarum cultured in supportive media, but different from O. stellarum cultured in living sperm cells of starfish (Leptasterias spp.). Also, the growth of the ciliate did not interfere with light, which was different from O. stellarum. Accordingly, the ciliate was classified as genus Mesanophrys and temporarily named as Mesanophrys sp. In addition, experimental infection confirmed that Mesanophrys sp. was the pathogen that infected farmed crabs. In summary, Mesanophrys sp. was first isolated and characterized in P. trituberculatus., (© 2020 John Wiley & Sons Ltd.)

Balantioides coli (syn. Balantidium coli) is an important zoonotic but usually neglected protozoa infecting human and a great number of animals, and the pig was considered to be the most important natural host and reservoir. However, no information about the infection of B. coli in pigs in northwestern China was available. In the present study, the prevalence and genetic diversity of B. coli in pigs in Shaanxi province were investigated. A total of 560 fecal samples were collected from pigs of four age groups in five different geographical regions and analyzed by using PCR targeting the ITS1-5.8S rRNA-ITS2 gene fragment. The infection of B. coli was detected in all age groups and regions, with the total prevalence of 16.8% (94/560). Significant differences (P < 0.01) in prevalence were found among four investigated age groups, with the highest in fatteners (38.8%) and the lowest in adults (5.7%). The prevalence was also significantly (P < 0.01) different among pigs from five sampling regions. Sequence analysis revealed two genetic variants, namely, A and B, in these investigated pigs, and both of them were detected in all age groups and regions, with the latter as the predominant one. Further, sixty-eight different haplotypes were found, with 19 and 49 belonged to genetic variants A and B, respectively. The findings in the present study indicated wide distribution and high diversity of B. coli in pigs in Shaanxi province and provided fundamental data for implementing control strategies on B. coli infection in pigs as well as other hosts in this province.

The ciliate species Balantioides coli can be cross-transmitted between humans and several animal species. Usually harmless, sometimes it can be pathogenic and cause the death of the host. In birds, B. coli has been confirmed in ostriches by genetic analysis, but the identification from South American greater rheas (Rhea americana) and lesser rheas (Rhea pennata pennata) is tentative. Since these species are reared for commercial purposes and for reintroduction into the wild, it is necessary to elucidate whether the ciliate from rheas is B. coli to minimize health risks for humans and for other domestic and wild animals. Individual parasite cells are collected from Argentinean isolates of reared greater rheas and of wild and reared lesser rheas, and their ITS region was PCR amplified; the cloning products were sequenced and compared with sequences available in public databases. The results have shown that several sequence types are expressed at the same time in the parasite cells, and all correspond to B. coli, confirming the possibility of cross-transmission of the parasite between wild and reared South American rheas and several mammal species and humans.

A total of 578 specimens of common carp (Cyprinus carpio) from eight the most significant and larger cyprinid aquaculture facilities in Macedonia (fish farms and cage culture systems) were examined for parasitological investigation. Protozoa Apiosoma piscicola was found in cage culture system on Globochica reservoir. In this fish farm, a total of 127 fish samples were examined for parasitological investigation, in which parasite infestation with A. piscicola was found on fins and gills in 79 specimens of common carp, in winter season. The prevalence of A. piscicola in common carp was 62.20%, while the mean intensity was 17.58. Our findings of A. piscicola in common carp (C. carpio) are first recorded in Macedonia. At the same time, common carp represent new host for A. piscicola in Macedonian waters.

Trichodinids are parasites generally found on gills and skin of a broad number of aquatic animals. Only a small number of endozoic species has been reported from the urinary tract, intestine and urogenital system in some fish, amphibians and molluscs. This is the first report on the presence of endozoic trichodinids in the spleen, kidney and liver of shorthorn sculpin (Myoxocephalus scorpius). In the present study, trichodinids displayed some of the typical morphological characteristics of endozoic trichodinids with narrow blades and straight rays of adhesive disc denticles. The parasites were observed at a relatively high prevalence (23.9%). There was a positive correlation between intensity of endozoic trichodinids in the internal organs and ectozoic trichodinids on the gills (R = 0.5, n = 46, P &lt; 0.001) whereas there was no correlation between intensity of endozoic trichodinids and the host's body length, body weight or liver weight. Infection levels of endozoic trichodinids were not dependent upon sculpin sex and there was no effect of sampling locations on prevalence and intensity of endozoic trichodinids.

During March to August of 2017, hundreds of leopard sharks ( Triakis semifasciata) stranded and died on the shores of San Francisco Bay, California, US. Similar mass stranding events occurred in 1967 and 2011, but analysis of those epizootics was incomplete, and no etiology was confirmed. Our investigation of the 2017 epizootic revealed severe meningoencephalitis in stranded sharks, raising suspicion for infection. We pursued a strategy for unbiased pathogen detection using metagenomic next-generation sequencing followed by orthogonal validation and further screening. We showed that the ciliated protozoan pathogen, Miamiensis avidus, was present in the central nervous system of leopard ( n=12) and other shark species ( n=2) that stranded in San Francisco Bay but was absent in leopard sharks caught elsewhere. This ciliated protozoan has been implicated in devastating outbreaks in teleost marine fish but not in wild elasmobranchs. Our results highlight the benefits of adopting unbiased metagenomic sequencing in the study of wildlife health and disease.

Survival during an epidemic is partly determined by host genetics. While quantitative genetic studies typically consider survival as an indicator for disease resistance (an individual's propensity to avoid becoming infected or diseased), mortality rates of populations undergoing an epidemic are also affected by endurance (the propensity of diseased individual to survive the infection) and infectivity (i.e. the propensity of an infected individual to transmit disease). Few studies have demonstrated genetic variation in disease endurance, and no study has demonstrated genetic variation in host infectivity, despite strong evidence for considerable phenotypic variation in this trait. Here we propose an experimental design and statistical models for estimating genetic diversity in all three host traits. Using an infection model in fish we provide, for the first time, direct evidence for genetic variation in host infectivity, in addition to variation in resistance and endurance. We also demonstrate how genetic differences in these three traits contribute to survival. Our results imply that animals can evolve different disease response types affecting epidemic survival rates, with important implications for understanding and controlling epidemics.

The ciliate Ichthyophthirius multifiliis is an important pathogen of freshwater fish that occurs in both temperate and tropical regions around the world. The purpose of present study was to report an outbreak of I. multifiliis in Steindachneridium parahybae from the Paraiba do Sul River in state of São Paulo (Brazil). The fins, tegument and gills of S. parahybae were examined for the presence of I. multifiliis, and blood parameters (Red Blood Cell, thrombocytes and leukocytes) were evaluated. All the examined fish (100%) were parasitized with I. multifiliis and the mean infection intensity was 15.5 parasites per fish. All the fish died 72 hours as a consequence of ichthyophthiriasis with alterations to the tegument coloration and open opercula. Red Blood Cell counts and hemoglobin concentration were low, indicating an anemic process.

The genus Chilodonella includes free-living ciliated protozoa as well as pathogenic species for freshwater fish, with Chilodonella hexasticha and Chilodonella piscicola being the most important ones. These parasites cause outbreaks with high mortalities among farmed freshwater fishes with great economic losses. There are few reports of these species in China, and their identification has been based mostly on their morphological characteristics. In the present work, the parasites causing five outbreaks occurring in China between 2014 and 2017 have been identified by morphological and genetic analysis. We provide the first records of Ctenopharingodon idella and Siniperca chuatsi as hosts of C. hexasticha, and of Procypris rabaudi and Schizothorax wangchiachii as hosts of C. piscicola. There are no differences in the gross pathological findings produced by C. hexasticha and C. piscicola, consisting in desquamation and necrosis of epithelial cells in the skin and gills and in severe fusion of gill lamellae. However, both species differ in their geographic distribution: C. piscicola was found in farms located at altitudes over 1500 m above sea level and with a water temperature ≤18 °C, while C. hexasticha was found in farms located at altitudes under 50 m above sea level and with a water temperature ≥21 °C. Present results confirm that C. hexasticha and C. piscicola are two different species that can be differenced by their morphology; however, their biological variability may lead to erroneous identifications and the diagnosis should be preferably based in genetic analysis including nuclear LSU rDNA and mitochondrial SSU rDNA sequences., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This paper characterizes the pattern of ectoparasite and endoparasite communities in an assemblage of 35 sympatric fish from different trophic levels in a tributary from the Amazon River system, northern Brazil. In detritivorous, carnivorous, omnivorous and piscivorous hosts, the species richness consisted of 82 ectoparasites and endoparasites, but protozoan ectoparasites such as Ichthyophthirius multifiliis, Piscinoodinium pillulare and Tripartiella sp. were dominant species predominated, such that they were present in 80% of the hosts. The taxon richness was in the following order: Monogenea > Nematoda > Digenea > Crustacea > Protozoa > Acanthocephala = Cestoda > Hirudinea. Among the hosts, the highest number of parasitic associations occurred in Satanoperca jurupari, Aequidens tetramerus, Hoplerythrinus unitaeniatus, Hoplosternum littorale, Cichlasoma amazonarum, Chaetobranchus flavescens, Squaliforma emarginata, Chaetobranchopsis orbicularis and Hoplias malabaricus. A weak positive correlation between ectoparasite abundance and length of the hosts was observed. Ectoparasite communities of detritivorous, carnivorous and omnivorous hosts were similar, but these differed from the communities of piscivorous hosts. Larval endoparasite species with low host specificity were the main determinants of the parasite infracommunity structure of the fish assemblage. Fish assemblage had few species of helminth that were specialist endoparasites, while many were parasites at the larval stage, infecting intermediate and paratenic hosts. Finally, carnivorous and omnivorous hosts harbored endoparasite communities that were more heterogeneous than those of detritivorous and piscivorous hosts. This result lends supports to the notion that the feeding habits of the host species are a significant factor in determining the endoparasites fauna.

Sixty suspected protozoan oocysts were demonstrated from 260 fecal samples collected from water buffaloes aged one month to seven years old with clinical signs of diarrhea in four provinces in the Philippines after conventional methods of isolation, sporulation, morphological characteristics and Kinyoun Acid Fast Staining techniques. The recovered protozoan oocysts were subjected to molecular analysis. Amplification of DNA extracted from recovered Eimeria oocysts using universal primers for the ITS-1 region of 18S rRNA revealed PCR products with 348 bp size demonstrated by samples collected from Benguet, La Union and Nueva Ecija provinces in the Philippines while DNA extracted from oocysts of suspected Cryptosporidium spp. samples that applied primers for the SSU of 18S rRNA registered PCR products but no genes were amplified from diarrheic water buffaloes from these provinces. Alignment of the DNA sequences of the suspected Eimeria and Cryptosporidium species revealed sequences for three isolates of Buxtonella sulcata with product lengths that varied from 235 to 252 bp. This is an initial observation on the involvement of B. sulcata in diarrhea condition of water buffaloes in the Philippines. Phylogenetic analysis of the three local isolates of B. sulcata revealed no similarity with other protozoan constructed according to Neighbor-Joining method.

Neobalantidium coli (Pomajbíková et al., 2013) is a cosmopolitan ciliate which colonizes the intestine of humans and animals. Pigs are the most important host and reservoir for this parasite, although others mammals have been described. Humans can acquire the disease through the ingestion of water and food contaminated with cysts and even from person to person contact. Farmers and slaughterhouse workers from rural areas of developing countries have an increased incidence of balantidiosis. In Argentina, despite swine production on family farms covers 70% of domestic consumption requirements; there is a lack of veterinary animal health planning which result in high rate of animal mortality, as well as environmental risk due to inefficient facilities and mismanagement of manure and effluents. At present there are no epidemiological data on balantidiosis in Argentina, except for isolated reports. Therefore, the aims of this study were to establish the frequency of N. coli in pigs raised under different conditions and to explore the zoonotic potential. In order to confirm the identity of Neobalantidium coli like-cysts founded in the feces, a set of N. coli specific primers based on 18S rRNA gene sequences was designed. The molecular identification of N. coli was performed in 88.9% (16 out of 18) of swine stool samples in which cysts had been visualized. The fecal samples obtained from pigs raised on more open farmland showed a lower percentage of N. coli than those obtained from animals raised in swine pens. On the other hand, molecular identification of N. coli was also performed in human feces. Pairwise comparison of sequences obtained from pigs and human fecal samples from the NW Region of Argentina showed a high percentage of similarity, indicating a possible zoonotic transmission., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: False kelpfish (Sebastiscus marmoratus) is one of the target species in artificial breeding in China, and is susceptible to infection by Cryptocaryon irritans, which is an obligate parasitic ciliate that lives in the epithelium of the fish gills, skin and fins. Here, we sought to understand the mechanisms of molecular immunity of S. marmoratus against C. irritans infection., Methods: We carried out an extensive analysis of the transcriptome of S. marmoratus immune-related tissues. A paired-end library was constructed from the cDNA synthesized using a Genomic Sample Prep Kit. Five normalized cDNA libraries were constructed using RNA from the control group and the four groups of C. irritans-infected fish. The libraries were sequenced on an Illumina Mi-Seq platform, and functional annotation of the transcriptome was performed using bioinformatics software., Results: The data produced a total of 149,983,397 clean reads from five cDNA libraries constructed from S. marmoratus immune-related tissues. A total of 33,291 unigenes were assembled with an average length of 1768 bp. In eggNOG (Evolutionary Genealogy of Genes: non-supervised orthologous groups) categories, 333 unigenes (0.94%) were assigned to defense mechanisms. In the immune system process sub-categories of gene ontology (GO) enrichment analysis, with the passage of time post-infection, the number of differentially expressed genes (DEGs) was reduced from 24 h to 48 h but then increased from 72 h to 96 h. Specifically, the immune-related differentially expressed genes (IRDEGs), which belong to the KEGG (Kyoto encyclopedia of genes and genomes) pathways, such as the complement and coagulation cascades, chemokine signalling pathways and toll-like receptor signalling pathways were mainly observed at 24 h post-infection., Conclusions: Infection with C. irritans resulted in a large number of DEGs in the immune-related tissues of S. marmoratus. The rapid and significant response of the S. marmoratus immune signalling pathways following C. irritans infection may be associated with their involvement in the immune process.

The present study describes a new species of Trichodina found in the mucus of the body surface of 137 farmed and wild silver catfish (Rhamdia quelen) located in southern Brazil and in the gills of 99 banded knife fish (Gymnotus sp.) captured in the basin of Pantanal. Smears of the body surface mucus and gills were air dried at room temperature and impregnated with silver nitrate and stained with Giemsa for analysis of the adhesive disc, denticles and macronucleus. Characterized as a medium trichodinid, Trichodina quelenii n. sp. resembles T. heterodentata and T. acuta. It differs from T. heterodentata by the shape of the blade and from T. acuta by the lack of central circle. Furthermore, the distinct shape of the blade of T. quelenii n. sp. differs from all previously described species for the genus, leaving no doubt it is a new species.

Schizothorax o'connori and Oxygymnocypris stewartii are two endangered endemic Tibetan fishes that thrive in the Lhasa River at an average altitude over 4000 m. During artificial reproduction of endemic Tibetan fishes, the juvenile fish of S. o'connori and O. stewartii experienced mass mortality event. The causative agent is diagnosed to be a ciliate parasite, Chilodonella piscicola (syn. C. cyprini), which is common in various fishes. Here, we supplemented its description based on the morphological and molecular data. The body of C. piscicola is oval, 30-60 × 25-40 μm in vivo. Cyrtos is hook-like, composed of 9-10 toothed nematodesmal rods. Somatic kineties usually contain seven right kineties and nine left kineties. Two parallel circumoral kineties revolve round the cyrtos, and one preoral kinety extends to the anterior end of the fourth left-most kinety. Terminal fragment kinety is linear and on the top left of dorsal side. Sequence alignments revealed that the present SSU rDNA and ITS1-5.8S-ITS2 sequences are both most similar to the sequences of C. uncinata with the similarities of 98.2 and 99.5%. The phylogenetic analyses showed that C. piscicola is sister to other Chilodonella species, whereas C. cyprini (FJ873805) cluster with Tetrahymena species. Molecular analysis shows that the ITS1-5.8S-ITS2 sequence of C. cyprini in GenBank is unreliable. Our study extended the host range of C. piscicola and supplemented and revised the molecular data. Besides, as far as we know, this is the first record of C. piscicola in Tibetan plateau.

Buxtonellosis is a disease caused by the ciliated protozoan Buxtonella sulcata (Jameson, 1926). B. sulcata is a common protozoan of ruminants and may result in subclinical infection or clinical disease including diarrhea. This study examined the prevalence of B. sulcata in cattle from Sanadaj province, Iran. Faecal samples were collected from cattle in the province from May 2013 to June 2014. A total of 217 cattle were selected randomly according to the age, sex, health, management system and season. In total, 99 cattle (45.63%) were found to be infected with B. sulcata. In adults, prevalence of B. sulcata infection (51.64%) was higher than calves (28.58%) and young cattle (40.55%). The prevalence of B. sulcata infection was also found to be higher in female (47.32%) than male (38.46) cattle. B. sulcata infection was significantly (p<0.05) higher in poor health cattle (body condition and weight) (79.54%) than healthy cattle (24.47%). This study demonstrates that cattle are highly susceptible to B. sulcata infection under a variety of housing and environmental conditions in this region of Iran. The study also demonstrates a significant effect of infection on cattle health.

A severe outbreak of scuticociliatosis occurred in Australian pot-bellied seahorse, Hippocampus abdominalis (Lesson, 1872), kept at the Vancouver Aquarium Marine Science Centre (Vancouver, British Columbia, Canada). Clinical signs included anorexia, lethargy, irregular respiration, and death. Cytology and histopathology revealed a high number of histophagous ciliated protozoa within the tissues. The parasite, identified as Philasterides dicentrarchi, was observed in several internal organs that appeared edematous and hemorrhagic upon postmortem examination. Severe histopathologic lesions were reported in particular in the ovary, the kidney, and the intestine. This infection was successfully treated with metronidazole via bath therapy. No further evidence of this parasite was found in the treated fish.

A comprehensive icthyoparasotological survey among estuarine and freshwater fishes of West Bengal, India revealed Trichodinella sunderbanensis sp. nov. and Trichodina acuta Lom, 1961 from an estuarine fish Mystus gulio (Hamilton, 1822) from the Vidyadhari river; Trichodina nandusi sp. nov. from a freshwater fish, Nandus nandus (Hamilton-Buchanan); Chilodonella hexasticha (Kiernik, 1909) Kahl, 1931 from freshwater fishes Labeo rohita (Hamilton, 1822); and Cyprinus carpio Linnaeus, 1758 from the Rupnarayan river. Taxonomic description of all the species based on wet silver nitrate impregnation method along with additional comments based on scanning electron microscopic descriptions of T. nandusi sp. nov. are also provided in this paper. Prevalence rate, morphometric parameters and comparisons with closely related species are also discussed.

Wild-caught European perch (Perca fluviatilis) were exposed in the laboratory to untreated bleached pulp and paper mill effluent in two separate experiments. The first experiment was conducted at 7-8°C using effluent concentrations of 5 and 10%, and the second experiment was conducted at ambient river temperature of 4-20°C using an effluent concentration of 1%. Trichodinid ciliates were identified and enumerated at the end of the exposure using a mucus subsampling technique from gill and skin as well as a formalin immersion technique, which provided total counts on each fish. Four different trichodinid species were identified on the fish. Prevalence of infection, mean number, and mean density of Trichodina spp. decreased on fish exposed to effluents compared with controls. Prevalence of infection, mean number, and mean density of Trichodinella epizootica decreased on fish exposed to 5% and 10% effluents but increased on fish exposed to 1% effluents compared with controls. These results demonstrate that trichodinid ciliates vary in their susceptibility to at least certain types of contaminants and cautions against using trichodinids as environmental indicators without delineating species.

Objective: The aim of this study was to determine the cytological features of 2 endocommensal ciliates, P. colpoidea and P. minuta belonging to genus Paraisotricha found in the hindgut of 15 Turk rahvan and 15 English and Arabic horses from Izmir, compare the morphological characters of species with their original descriptions and previous reports and discuss the similarities and differences., Methods: The cytological features of two endocommensal ciliates were investigated with the pyridinated silver carbonate impregnation and silver nitrate impregnation techniques at the level of light microscopy., Results: Specimens from our horses were found to be similar to the original descriptions on the basis of cytological features, morphological characters and biometric data., Conclusion: We have concluded that the geographical variation and feeding habits of the host animals are important for evaluating the biometric data of species.

Trophozoites of Troglocorys cava were detected in all but one of the wild chimpanzee populations from Rubondo Island (Tanzania), with a prevalence ranging between 20% and 78%. However, the ciliate was absent in all captive groups. Prevalence appeared to increase with the number of sequential samples taken from a particular individual and reached 95.5% in wild individuals sampled at least 4 times., (© 2011 The Author(s) Journal of Eukaryotic Microbiology © 2011 International Society of Protistologists.)

Fish parasites are used to monitor long-term change in finfish grouper mariculture in Indonesia. A total of 210 Epinephelus fuscoguttatus were sampled in six consecutive years between 2003/04 and 2008/09 and examined for parasites. The fish were obtained from floating net cages of a commercially run mariculture facility that opened in 2001. The fauna was species rich, consisting of ten ecto- and 18 endoparasite species. The ectoparasite diversity and composition was relatively stable, with the monogeneans Pseudorhabdosynochus spp. (83-100% prevalence, Berger-Parker Index of 0·82-0·97) being the predominant taxon. Tetraphyllidean larvae Scolex pleuronectis and the nematodes Terranova sp. and Raphidascaris sp. 1 were highly abundant in 2003/04-2005/06 (max. prevalence S. pleuronectis 40%, Terranova sp. 57%, Raphidascaris sp. 1 100%), and drastically reduced until 2008/09. These parasites together with the prevalence of Trichodina spp., ecto-/endoparasite ratio and endoparasite diversity illustrate a significant change in holding conditions over the years. This can be either referred to a definite change in management methods such as feed use and fish treatment, or a possible transition of a relatively undisturbed marine environment into a more affected habitat. By visualizing all parameters within a single diagram, we demonstrate that fish parasites are useful bioindicators to monitor long-term change in Indonesian grouper mariculture. This also indicates that groupers can be used to monitor environmental change in the wild. Further taxonomic and systematic efforts in less sampled regions significantly contributes to this new application, supporting fish culture and environmental impact monitoring also in other tropical marine habitats.

The morphology, infraciliature, silverline system, and the small subunit ribosomal RNA (SSU rRNA) of the little-known marine scuticociliate Pseudocohnilembus longisetusThompson, 1965 from the diseased black rockfish Sebastes schlegelii in Korea were studied. This scuticociliate possessed the typical characteristics of the genus Pseudocohnilembus, but could be discriminated from Pseudocohnilembus hargisi, and Pseudocohnilembus persalinus in terms of the body size, shape, the number of somatic kineties and kinetids in somatic kinety 1, and the number/position of contractile vacuole pores. The SSU rRNA gene of P. longisetus was sequenced in order to gain a better understanding of appropriate phylogenetic classification. The SSU rRNA was 1754 bp and the sequence was deposited in GenBank under accession number FJ899594. The SSU rRNA gene sequences of P. longisetus had an identity of 98.1%, 96.8% and 95.3% with P. hargisi, P. persalinus, and Pseudocohnilembus marinus SSU rRNA sequences, respectively. Our population of P. longisetus belonged to the genus Pseudocohnilembus and was in an isolated position based on the SSU rRNA gene tree, which was consistent with the conclusions based on the morphological studies. However, further investigation is required to determine the pathogenicity of this species., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The effect of five probiotics, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus sakei, Bacillus subtilis, and Saccharomyces cerevisiae as individual and mixed enriched diet on the seasonal prevalence, activity and intensity of Uronema marinum infection in olive flounder Paralichthys olivaceus is reported. The growth performance, feed efficiency, blood biochemistry, survival rate, and non-specific immune response of U. marinum infected olive flounder on week 0, 1, 2, 4, 6, and 8 were quantified. The prevalence and infection intensity reached a peak from June to December and then it declined from December to March. The scuticocidal activity in the serum was significantly higher when fed with L. plantarum, L. acidophilus, and S. cerevisiae diets on weeks 2-8. All enriched diets significantly enhanced the weight gain significantly between week 6 and 8; the feed efficiency registered a significantly increase from week 4 to 8 when compared to infected fish fed with control diet. Infected fish fed with L. plantarum-supplemented diet had higher survival rate than with other enriched diets. The serum aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels significantly increased when fed with L. plantarum, L. acidophilus or S. cerevisiae-supplemented diet. Total protein (TP) and glucose (GLU) level significantly increased with any enriched diet from week 4 to 8. The superoxide anion production and serum lysozyme activity registered a significant increase when fed with L. plantarum, L. acidophilus, and S. cerevisiae-supplemented diet from week 4-8. The present study concludes that L. plantarum, L. acidophilus, and S. cerevisiae-supplemented diets act as immunostimulants enhancing the growth, feed efficiency, blood biochemistry, survival rate, and non-specific immune response in U. marinum infected olive flounder., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

This study characterises morphologically Trichodina heterodentata Duncan, 1977 from channel catfish, Ictalurus punctatus (Rafinesque, 1818) in the State of Santa Catarina, Brazil. Body and gill smears were air-dried at room temperature, impregnated with silver nitrate and/or stained with Giemsa. Ten characteristics were selected to compare the present material with other morphological characterisations of T. heterodentata. Prevalence rate was 100%, mean intensity 89,333.70 (3,125 to 299,100 parasites per host). Trichodina heterodentata was considered medium-sized trichodinid with mean body diameter 59.4 +/- 8.5 microm, denticulate ring 38.5 +/- 4.5 microm, adhesive disc 60.2 +/- 6.7 microm diameter and 24.4 +/- 1.6 denticles. In relation to previous reports of T. heterodentata this material resembles in 90% of the analysed characters. This work confirms the biometrical variation that exists in the different populations of T. heterodentata. A list of hosts and comparative measurements of T. heterodentata are presented and the channel catfish is considered a new host.

Intestinal entodiniomorphid ciliates are commonly diagnosed in the feces of wild apes of the genera Pan and Gorilla. Although some authors previously considered entodiniomorphid ciliates as possible pathogens, a symbiotic function within the intestinal ecosystem and their participation in fiber fermentation has been proposed. Previous studies have suggested that these ciliates gradually disappear under captive conditions. We studied entodiniomorphid ciliates in 23 captive groups of chimpanzees, three groups of captive bonobos and six populations of wild chimpanzees. Fecal samples were examined using Sheather's flotation and Merthiolate-Iodine-Formaldehyde Concentration (MIFC) methods. We quantified the number of ciliates per gram of feces. The MIFC method was more sensitive for ciliate detection than the flotation method. Ciliates of genus Troglodytella were detected in 13 groups of captive chimpanzees, two groups of bonobos and in all wild chimpanzee populations studied. The absence of entodiniomorphids in some captive groups might be because of the extensive administration of chemotherapeutics in the past or a side-effect of the causative or prophylactic administration of antiparasitic or antibiotic drugs. The infection intensities of ciliates in captive chimpanzees were higher than in wild ones. We suppose that the over-supply of starch, typical in captive primate diets, might induce an increase in the number of ciliates. In vitro studies on metabolism and biochemical activities of entodiniomorphids are needed to clarify their role in ape digestion.

Philasterides dicentrarchi is a histophagous scuticociliate causes fatal scuticociliatosis in farmed olive flounder Paralichthys olivaceus. The average monthly prevalence of scuticociliatosis due to P. dicentrarchi infections was increased from May to July (40+/-3.1% to 79.4+/-1.7%) and it decreased from August to November (63+/-2.3% to 30+/-2.6%) in olive flounder farms at Jeju Island, South Korea during 2000-2006. The prevalence of mixed infection along with Vibrio spp. bacterial infection was 49+/-7.2% than that of other mixed infection. At present no effective control measure for P. dicentrarchi infection has been described and large production losses continue. In the present study, formalin, hydrogen peroxide and Jenoclean chemotheraputants were used for bath treatment. Among Jenoclean at a low concentration of 50ppm proved effective. The results were confirmed with in vitro motility assessments and morphological changes scoring system in P. dicentrarchi. On the other hand, similar trend was noted following hydrogen peroxide treatment at this concentration, but formalin was only moderately effective. Either hydrogen peroxide or Jenoclean are the promising compounds effective at low concentrations with short application time for P. dicentrarchi. Therefore, these substances were evaluated on day 10, 20 and 30 for their ability to enhance innate immune response and disease resistance against P. dicentrarchi in olive flounder after chemotheraputants bath treatment with 100ppm for 30min per day. All the tested immune parameters were enhanced by treatment with Jenoclean, but not formalin and hydrogen peroxide. These findings suggest that Jenoclean bath treatment can be used for ensuring the heath of cultured marine fish against internal parasites such as P. dicentrarchi., (Crown Copyright 2009. Published by Elsevier Inc. All rights reserved.)

The histophagous scuticociliate Philasterides dicentrarchi causes fatal scuticociliatosis in farmed olive flounder Paralichthys olivaceus. The average monthly prevalence of scuticociliatosis with P. dicentrarchi infections was very high from May to July (40+/-3 to 79+/-2%) in olive flounder at farms of Jeju Island, South Korea, from 2000 to 2004. The prevalence of mixed infection along with Vibrio spp. infection was higher (49+/-8%) than that of scuticociliatosis alone. To date no effective control measure for P. dicentrarchi infection has been described and large economic losses continue. In the present study 3 chemotheraputants (formalin, hydrogen peroxide and Jenoclean) were used. Among these, bath treatment with Jenoclean at a low concentration of 50ppm proved effective; the results were confirmed with in vitro motility assessments and morphological changes in P. dicentrarchi. A similar trend was noted following hydrogen peroxide treatment. However, formalin was only moderately effective at this concentration. Therefore, hydrogen peroxide and Jenoclean are the promising compounds effective at low concentrations with short application time.

We examined stool samples for trophozoites of the entodiniomorphid ciliate Troglodytella abrassarti Brumpt and Joyeux, 1912, from a habituated group of chimpanzees (Pan troglodytes schweinfurthii) at Mahale Mountains National Park in western Tanzania. In our study, fresh fecal samples from identified individuals were collected immediately after defecation and fixed in 10% formalin. In total, 52 samples from 38 chimpanzees (61% of 62 chimpanzees in the group) were examined using a direct smear method. A stool sample from an individual collection date from an individual chimpanzee was examined up to 3 separate times before it was called negative. Forty-eight (92%) of the 52 samples were positive, and stools from 37 (97%) of the 38 chimpanzees were positive for trophozoites of T. abrassarti. The high prevalence of T. abrassarti in these chimpanzees is consistent with previous reports of this organism in chimpanzees.

Hemiprorodon gymnoposthium was investigated in the intestine of horses, found in Cyprus. It was found in four of fifth horses examined and thus had a frequency of appearence of 80%. This study reports for the first time the presence of Hemiprorodon gymnoposthium in the intestine of Equids in Cyprus. In addition, it is the second report from the world. Specimens were found to be similar to the original description on the basis of morphological characters and biometric data.

Ciliates associated with fish mortalities in a New Zealand hatchery were identified by DNA sequencing of the small subunit ribosomal RNA gene (SSU rRNA). Tissue samples were taken from lesions and gill tissues on freshly dead juvenile groper, brain tissue from adult kingfish, and from ciliate cultures and rotifers derived from fish mortality events between January 2007 and March 2009. Different mortality events were characterized by either of 2 ciliate species, Uronema marinum and Miamiensis avidus. A third ciliate, Mesanophrys carcini, was identified in rotifers used as food for fish larvae. Sequencing part of the SSU rRNA provided a rapid tool for the identification and monitoring of scuticociliates in the hatchery and allowed the first identification of these species in farmed fish in New Zealand.

In 2008, inland waterways in Catalonia (northeast Iberian Peninsula, Spain) experienced one of the worst droughts recorded in this region in recent decades. During this period, an epizootic of Ichthyophthirius multifiliis was detected for the first time in a Mediterranean stream, with 21% prevalence in a population of redtail barbs Barbus haasi. Environmental features and the fish population in this stream were compared during 2007-2009. Fish density and the average fish size were reduced significantly after the outbreak of I. multifiliis in this population. During 2008, parasitized fish were significantly larger than nonparasitized fish. In addition, a significant, positive correlation was found between parasite load and fish size. The origin of I. multifiliis is unknown, but an introduced species detected in April 2007 may have carried it. The combination of stress to the redtail barbs due to suboptimal conditions and favorable environmental conditions for parasite multiplication (e.g., suitable water temperature and low water flow) could have enhanced fish susceptibility to the parasite in April 2008. Further studies are needed to establish the incidence of freshwater fish diseases in Mediterranean watersheds, and water management policies should be reviewed to improve the conservation of native fish fauna.

The entodiniomorph ciliates (Ciliophora: Entodiniomorphida) are endosymbiotes widely found in the intestines of herbivorous mammals. These commensals commonly occur in the Artiodactyla and Perissodactyla and have also been described in the Proboscidea, Primates, Rodentia, and Diprotodontia. This study reports the first finding of a ciliate in a member of order Carnivora, the maned wolf (Chrysocyon brachyurus). Fecal samples from wild and captive maned wolves were screened using ethyl acetate sedimentation. Prevalence in fecal samples collected from free-ranging maned wolves in Brazil was 40% (6 of 15). Fecal samples from two of four captive individuals from the St. Louis Zoo also had the same species of ciliate. The largely frugivorous diet of the maned wolf likely explains the occurrence of these normally herbivore-associated endosymbiotes in a carnivore.

Blepharocorys curvigula Gassovsky, 1919 found in the intestine of domestic horses (Equus caballus Linnaeus, 1758), living in the vicinity of Izmir was investigated. It was seen in nine of the thirteen horses examined (69%). This study reports the presence of Blepharocorys curvigula in the intestine of Equids for the first time in Turkey. Specimens were found to be similar to the original descriptions on the basis of morphological characters and biometric data.

A study was conducted to ascertain the influence of a thermal discharge on the health and parasites of a coastal cold-water flatfish, the winter flounder (Pleuronectes americanus), a species sensitive to environmental change. Flounder were sampled in spring 1998 and 1999 beneath the plume and at reference sites north and south up to 1 km from the discharge. Species diversity and estimates of abundance of macroscopic algae, invertebrates, and fish were also recorded. After capture by scuba divers, a comparison of condition factor, organ indices, blood values, histology, and parasites was made between groups of fish from the discharge and reference sites. Diversity and abundance of algae, invertebrates, and fish were considerably greater beneath the plume than at the reference sites. The thermal water had no apparent effect on flounder taken beneath the plume, but it affected both its ecto- and endoparasites. Prevalence and mean abundance of Cryptocotyle lingua metacercariae were significantly greater, whereas Trichodina jadranica and Gyrodactylus pleuronecti were less on the gills of fish sampled beneath the plume than at the reference sites. Four endoparasites, i.e., Ceratomyxa drepanopsettae, Steringophorus furciger, Macvicarius soleae, and Lecithaster gibbosus were significantly more abundant in the reference samples. These results suggest that environmental change affected transmission of the parasites of winter flounder exposed to the thermal effluent.

During the years 2004 and 2005 high mortalities in turbot Scophthalmus maximus (L.) from a fish farm in the north of Portugal were observed. Moribund fish showed darkening of the ventral skin, reddening of the fin bases and distended abdominal cavities caused by the accumulation of ascitic fluid. Ciliates were detected in fresh mounts from skin, gill and ascitic fluid. Histological examination revealed hyperplasia and necrosis of the gills, epidermis, dermis and muscular tissue. An inflammatory response was never observed. The ciliates were not identified to species level, but the morphological characteristics revealed by light and electronic scanning microscopes indicated that these ciliates belonged to the order Philasterida. To our knowledge this is the first report of the occurrence of epizootic disease outbreaks caused by scuticociliates in marine fish farms in Portugal.

The ciliate protozoon that lives in the rumen of Cypriot domestic goats and belongs to the genus Ophryoscolex from the (Capra hircus) was investigated. As the result of our investigation, a species [Ophryoscolex purkynjei] including four formae [O. p. f. purkynjei, O. p. f. bifidobicinctus, O. p. f. bicoronatus and O. p. f. tricoronatus] were detected. The present study reports for the first time the presence of Ophryoscolex purkynjei f. bifidobicinctus in the rumen of goats. All of the formae determined were compared with their original descriptions and previous reports and the similarities and differences were discussed. It was also determined that the microfauna of the genus Ophryoscolex in the rumen of the Cypriot domestic goat is more diverse than that in goats of other countries.

In the present study, Pseudocohnilembus persalinus was first reported as a species causing scuticociliatosis in olive flounder Paralichthys olivaceus. Based on the stained specimens, P. persalinus was clearly differentiated from Uronema marinum, which has been shown to be a cause of scuticociliatosis in farmed olive flounder in Korea from its characteristic oral infraciliature structure. The 1754 bp small subunit ribosomal RNA (SS rRNA) gene sequence of P. persalinus showed 95% homology with the partial sequence of P. hargisi SS rRNA. Moreover, multiplex PCR based on the species-specific amplification of the SS rRNA gene sequence enabled us to distinguish P. persalinus from U. marinum in a simple and rapid manner. P. persalinus was clearly differentiated from U. marinum even when the host was infected simultaneously with both species. These data suggest that the multiplex PCR procedure would make it possible to avoid the cumbersome and time-consuming procedures of morphological analysis for the definitive identification of ciliates.

In the course of identifying scuticociliates recently obtained from systemically infected olive flounder Paralichthys olivaceus in Korea, we found a scuticociliate species whose small subunit ribosomal RNA (SS rRNA) gene was not amplified by species-specific primers previously designed for Uronema marinum and Pseudocohnilembus persalinus. By studying morphological characteristics of wet-mounted and stained specimens, we identified the species as Philasterides dicentrarchi, which has been reported to cause systemic infection in the European sea bass Dicentrarchus labrax and turbot Scophthalmus maximus. In this study, we compared morphological characteristics of our specimens with previously reported Philasterides species, including P. dicentrarchi, and sequenced the SS rRNA gene in order to design P. dicentrarchi specific primers. This is the first report on scuticociliatosis caused by P. dicentrarchi from marine fish in Asia.

We report the results of a two-year study in the Svisloch River (Minsk, Belarus) on the dynamics of infection in Dreissena polymorpha by nematodes and three ciliate species Conchophthirus acuminatus, Ophryoglena sp., and Ancistrumina limnica. Although these endosymbionts were present in most of the samples, their prevalence and infection intensity differed significantly. C. acuminatus and A. limnica infection intensities in both years of the study had a maximum in summer and were positively correlated with water temperature. In contrast, Ophryoglena sp. and nematode infection intensities were considerably lower in summer versus winter and were negatively correlated with temperature. In the first long-term study to monitor the size and reproductive rate of C. acuminatus, we found that mean length was negatively correlated with temperature and that temperature was positively correlated with asexual reproduction, with a peak of cell division in April as water temperatures increased.

This study, conducted in the Dnieper-Bug Canal in Belarus, is the first to monitor the seasonal (June-November) dynamics of infection with the parasitic ciliate Ophryoglena sp. in a zebra mussel (Dreissena polymorpha) population. Mean population prevalence and intensity of infection varied, respectively, from 11 to 62% and from 0.9 to 24.1 ciliates/mussel. Mean prevalence was highly correlated with mussel length in mussels <20 mm (R(2)=0.97) and was lower in larger mussels. Mean infection intensity in mussels 1-25 mm long was similarly correlated with their size (R=0.98), reached a maximum in the 20-25 mm size-class, and then sharply decreased, thus providing evidence, albeit limited, that high intensity of infection might be lethal. Transinfection of zebra mussels by Ophryoglena sp. was achieved in the laboratory-a first for a protozoan parasite of D. polymorpha; from an initial complete lack of infection, mean prevalence and intensity rose, respectively, to 86.7% and 8.3 ciliates/mussel., ((c) 2002 Elsevier Science (USA).)

One liter of rumen fluid containing 4.7 x 10(4) ciliates/ml, representing four genera including nine species of ciliates from a Japanese sika deer was inoculated into two unfaunated Japanese shorthorn calves. Two weeks after inoculation, all species originally present in the inoculum were subsequently detected in the rumen fluid of one or both calves. Ciliate densities ranged from 10(5)-10(6) cells/ml over the remainder of the 33-wk experiment. The inoculum contained Diplodinium rangiferi. which lacks caudal appendages, as is characteristic for the species. However, three weeks later, the rumen fluid of both calves contained D. rangiferi, which possesses caudal appendages varying from a single spine to multiple spines with a complicated furcate appearance. The caudal spines of D. rangiferi did not disappear during the experiment, even when the diet of the calves was switched to the ration of sika deer from which the inoculum was obtained.

Two outbreaks of scuticociliatosis affecting farmed turbot Scophthalmus maximus in Galicia are described. Moribund fish showed cutaneous ulcers, darkened skin, swimming behaviour alterations, exophthalmos, and/or abdominal distension as a result of accumulation of ascitic fluid in the body cavity. Ciliates were detected in fresh mounts of practically all organs and tissues, including the blood and ascitic fluid. Histopathological studies revealed severe encephalitis and meningitis (associated with different degrees of softening or liquefaction of the brain), necrosis of the hepatic parenchyme, severe oedema of the intestinal wall, degeneration of muscle fibres, hyperplasia of the branchial epithelium, and/or vascular and perivascular inflammation. In some cases, parasites are surrounded by abundant monocytic and lymphocytic infiltrate. We report the morphological and biometric characteristics of this ciliate, which allow identification as Philasterides dicentrarchi. We discuss possible routes of entry into the host, and environmental factors possibly facilitating infection.

Investigations on the occurrence of trichodinid ciliates from fish caught in the Kiel Bight and Kiel Fjord (western Baltic Sea) were carried out between September 1996 and March 1997. Smears of the gills, fins, and skin of 120 Gadus morhua and 92 Platichthys flesus caught by fish traps and trammel nets revealed the presence of trichodinid ciliates. According to the fish species and locality, different prevalences and densities of trichodinid ciliates were found. Fish caught in the Kiel Bight revealed a lower prevalence of trichodinid ciliates on their gills (P. flesus 74.2%, G. morhua 3.8%) in comparison with fish of the same species and size caught in the Kiel Fjord (P. flesus 75.0%, G. morhua 26.2%). In both areas, P. flesus was more heavily infested than G. morhua. Seasonal changes in the prevalence of infestation of P. flesus between autumn and winter in the Kiel Fjord are proposed to be linked to an increase in bacterial biomass during winter. The fish ecology in combination with the total number of bacteria in the fish environment is discussed as an important factor influencing the abundance of trichodinid ciliates. The present data suggest the use of trichodinid ciliates as an indicator for eutrophication in brackish-water environments.