Mean Abundance Research Articles

Intact shallow and mesophotic assemblages of large carnivorous reef fishes underscore the importance of large and remote protected areas in the Coral Triangle

Abstract Overfishing remains a threat to coral reef fishes worldwide, with large carnivores often disproportionately vulnerable. Marine protected areas (MPAs) can restore fish populations and biodiversity, but their effect has been understudied in mesophotic coral ecosystems (MCEs), particularly in the Coral Triangle. Videos were analysed from baited remote underwater video systems deployed in 2016 to investigate the assemblage structure of large carnivorous fishes at shallow (4–12 m) and mesophotic (45–96 m) depths in two of the largest and most isolated MPAs in the Philippines: an uninhabited, fully no‐take MPA enacted in 1988 (Tubbataha Reefs Natural Park) and an archipelagic municipality surrounded by an extensive but not fully no‐take MPA declared in 2016 (Cagayancillo). Taxa focused on were groupers (Serranidae), snappers (Lutjanidae), emperors (Lethrinidae), jacks (Carangidae) and the endangered Cheilinus undulatus (Labridae). Mean abundance and species richness were not greater in TRNP than in Cagayancillo regardless of depth despite long‐term protection in the former. Limited impacts of fishing in Cagayancillo may explain this result. Differentiation of fish assemblages was evident between TRNP and Cagayancillo but more obvious between depths at each location, probably due more to habitat than MPA effects. In Cagayancillo, overall carnivorous reef fish, grouper and jack mean abundance were 2, 2 and 10 times higher, respectively, at mesophotic depths, suggesting that MCEs can serve as deep refugia from fishing. These findings of differentiation between depths and higher abundance of certain taxa in mesophotic depths emphasize that MCEs are distinct from shallow reefs, serve as important habitat for species susceptible to overfishing and, thus, must be explicitly included in the design of MPAs. This study also highlights the value of maintaining strict protection of MPAs like TRNP for the Coral Triangle and an opportunity to safeguard intact fish assemblages in Cagayancillo by expanding its no‐take zones.

Environmental influence on abundance and infection patterns of snail intermediate hosts of liver and intestinal flukes in North and Central Vietnam.

Liver and intestinal flukes (LIF) are important groups of foodborne zoonotic trematodes (FZTs) in Southeast Asia, including Vietnam. Their complex life cycles require specific freshwater snail species as the obligatory first intermediate hosts. In 2019, we conducted a longitudinal study in Yen Bai and Thanh Hoa provinces in North and Central Vietnam, respectively, to investigate the diversity of LIF and their infection prevalence in relation to snail host abundance and environmental factors. Using a combination of morphological and molecular identification techniques, we identified 10 LIF species infecting 11 snail host species. We observed significant seasonal variation in the mean abundance of several snail host species, with the majority of snails collected during the spring. We also detected seasonal changes in LIF species composition, with the highest species richness reported in the spring. Clonorchis sinensis and Fasciola gigantica, two medically important human liver flukes in Asia, were found only in the spring in Yen Bai. Our study revealed that not all snail host species have the same probability of becoming infected, and we recorded seasonal variations in the prevalence of LIF infection in different snail species in relation to water parameters.

Effects of Season, Habitat, and Host Characteristics on Ectoparasites of Wild Rodents in a Mosaic Rural Landscape.

Despite the large number of studies on rodent ectoparasites-most of them vectors of epidemiologically important pathogens-infestation patterns remain poorly understood in various ecological contexts, such as the highly patchy agricultural landscapes. We aimed to relate the infestation of rodents to temporal, habitat, and host variables. We assessed the difference in parasite prevalence and mean abundance depending on host sex, age, and body weight, season, and land use intensity. Furthermore, we analysed the effect of host species abundance and the differential responses of parasites in main and minor host species. The field survey was conducted in a rural landscape in southern Transylvania (Romania) between June and September 2010-2011. We live-trapped small mammals, collected the ticks and fleas, and recorded the presence of lice and mites. Overall, we found the same infestation patterns largely reported in the literature: higher prevalence and mean abundance in heavier adult males, significant seasonality and differences among host species, and evidence of the dilution effect. The uniqueness of our study system was the negative effect of the land use intensity on the prevalence and mean abundance of parasites, explained by the highly patchy mosaic landscape.

Survey of mosquitoes larvae at Bayero University, Kano students’ hostels (Old Campus) (Culicidae: Diptera)

The risk of contracting mosquito-borne diseases upon being bitten by an infected mosquitoraises serious health concerns for both staff and students in educational settings. Consequentlya survey was conducted to identify various mosquito species and breeding sites within the oldcampus hostels of Bayero University, Kano, during January and February 2023. The surveyencompassed breeding sites such as stagnant pools of water, drainages, gutters, and discardedcontainers. Mosquito larvae were sampled using dippers and scoops, and their enumerationwas performed with a Pasteur pipette. Three genera were identified: Anopheles, Aedes, andCulex spp. A total of 1,115 larvae were sampled from six locations, per volume of water comprising three each from female hostels and three from male hostels respectively. Theprevalence of mosquitoes was higher in female hostels (785 larvae, 69.4%) compared to malehostels (370 larvae, 32.7%). In female hostels, Aedes sp. exhibited greater abundance (400, 50.9%) than Culex sp. (337, 42.9%), with Anopheles sp. being the least abundant (48, 6.11%).Conversely, in male hostels, Culex sp. dominated with 186 (50.2%), followed by Aedes sp. with 179 (48.3%), while Anopheles sp. was the least abundant with 5 (1.35%). Consequently, the mean abundance of mosquitoes between male and female hostels demonstrated a significantdifference. This study contributes valuable insights into the larval habitats of mosquitoes in thestudents’ hostels of Bayero University, Kano, specifically during the dry season. Factors suchas student activities, inadequate sensitization, and poor sanitation were identified as majorcontributors to the creation of breeding sites for mosquitoes in the hostels.

Avian Diversity in and around Wetland of National Importance ‘Pariyej Community Reservoir’, Gujarat, India

The Pariyej Community Reservoir (PCR) is a freshwater reservoir in the Kheda district of Gujarat State, India. The PCR is also listed in Asian Directory of Wetlands. It is an important water storage reservoir; falls in the 4-B Gujarat Rajwara region of Central Gujarat, India. The present study was carried out for the period of one year (March, 2021 to February, 2022) to assess the status of avian diversity in terms of its species richness, abundance, and density. 116 bird species from 20 orders, 51 families, and 100 genera were documented. 75 species (64.4%) were resident, whereas 41 (35.3%) were migratory or seasonal. With respect to abundance, 41species (35.34%) were abundant, 39 species (33.6%) common, and 36 rare species (31.0%). The maximum total abundance (1707 individuals) was found at Site 1 in winter season with mean abundance of 427 individuals, total density (114 individuals/sq.km)and mean density (29 individuals/sq.km). The minimum total abundance (288 individuals) was recorded at Site2 in monsoon season with mean abundance of 72 individuals, total density (19individuals/sq.km) and mean density (5 individuals/sq.km).The present investigation reflects the good species richness of avian specieswith respect to order: family: genera: species ratioi.e., 1: 2.55: 5.0: 5.8. This indicates the flourishing harboring capability of PCR during peak winter period, which could be due to sustenance of rich biotic elements. The PCR has been declared as Sanctum sanctorumfor the refuge of migratory as well as local migrant birds, which is proved to be a wetland of national importance.

The first record of ostrich feather louse (Struthiolipeurus struthionis) collected from farmed ostriches (Struthio camelus) in the United Arab Emirates.

Ostrich (Struthio camelus) farming in the United Arab Emirates (UAE) is a relatively new field of farming. Farmed ostriches are susceptible to ectoparasite infestation, which affects their production. This study was conducted to estimate the prevalence of ectoparasites on ostriches raised on a farm in Abu Dhabi Emirate. The feathers of 42 ostriches (26 females and 16 males) were collected and morphologically examined for ectoparasites. In total, 283 lice (89 males and 194 females) were collected from birds. However, there were no ticks or other ectoparasites. Lice were preserved in 1.5 mL tubes containing 70% ethanol and were later identified using taxonomic keys. The prevalence, mean intensity of infection, and mean abundance were estimated. One louse species, Struthiolipeurus struthionis was identified. To the best of our knowledge, this is the first report of S. struthionis in ostriches raised in the UAE with an overall prevalence of 88%. The prevalence of lice was significantly higher in July (100%) than that in May (66.7%). Likewise, the mean intensity and abundance of lice were significantly higher in June (10.6 and 9.94, respectively) than in May (3.25 and 2.2, respectively). The high prevalence of lice poses a serious risk to ostrich farming by negatively affecting the health and productivity of ostriches.

Variation in the levels of anisakid infection in the European anchovy Engraulis encrasicolus (Linnaeus) from the Bay of Biscay during the period 2000-2023 (ICES Subarea 8).

The European anchovy Engraulis encrasicolus is one of the most important commercial species in the Bay of Biscay (ICES Subarea 8), and our analysis focused on the analysis of the temporal mean abundance, prevalence, and intensity of Anisakis spp. larvae species in anchovies from ICES Subarea 8 in the years 2000, 2001, 2014-2016, and 2019-2023. Prevalence in adult individuals of anchovy was only 1% in 2000 but increased to 90% in 2014. Since 2015, the prevalence has decreased, and the number of individuals affected in 2023 accounted for 17.6%. The mean abundance showed a similar trend, with a peak of 3.79 nematodes/anchovy in 2014, falling to 0.21 in 2023. The species A. simplex sensu stricto and A. pegreffii were identified by PCR/SANGER sequencing and PCR/RLFP techniques in 2019 and 2020. Anisakis simplex (s.s.) was the most abundant species and, according to the results returned by these two techniques, it accounted for an average of 62.4% and 52.1% of total nematodes in 2019 and 2020, respectively. The results of studies monitoring infection levels in anchovies showed that the mean abundance and prevalence changed over the course of the study period and that the proportion of different species of Anisakis is also subject to variation from year to year.

Parasitos de peixes de um rio costeiro neotropical dentro de um hotspot de biodiversidade

Abstract: Aim We investigated the ichthyofauna parasite component community across a gradient of anthropogenic pressures of the Guaraguaçu River, south Brazil, a Neotropical river of central importance for biodiversity conservation. Methods After fish sampling, all fish were identified, measured, weighed and eviscerated. The viscera and gills were inspected for parasite screening and subsequent identification. Parasite diversity estimators were calculated for the most abundant host species. Results A total of 159 host specimens from 12 species were examined, being 140 (88.05%) found to be infected with at least one parasite, including 14 new parasite occurrences. The most widely distributed parasite was the nematode Contracaecum sp., found in 8 host species. The highest mean infection intensity and mean abundance was observed for the monogenean Aphanoblastella mastigatus, infecting the Silver catfish Rhamdia quelen. The Shannon-Wiener, Jost and Simpson indexes were higher for the more abundant fishes, except for the Trahira Hoplias malabaricus. Most host species harbored parasites in poorly aggregated distribution, according to the discrepancy index. The Berger-Parker index showed monogenean dominance in all hosts except for H. malabaricus. We found little evidence for parasite infracommunity changes across the gradient of the river. Conclusions We described the infection patterns in an important Neotropical river. The new parasite occurrences highlight the contribution of our study. Fish-parasite interactions changed throughout the river stretches, and we argue that it does not necessarily means changes in diversity and abundance of parasite within species, but the rearrange of interactions. Moreover, it seems that parasites are more abundant in most impacted sites, another reason to continue the monitoring.

Assessing the influence of abiotic factors on small pelagic fish distribution across diverse water layers in the Northwest Pacific Ocean through acoustic methods

The Northwest Pacific Ocean is one of the most productive fisheries in the world, with small pelagic fish constituting a substantial portion of its fishery resources. Changes in abiotic factors can affect the distribution of marine fish, but there are limited studies on the relationship between abiotic factors and fish density in a vertical direction. This study used acoustic measurement data collected by the scientific research vessel “Songhang” equipped with a Simrad EK 80 scientific echosounder from June to July 2022, to estimate the small pelagic fish resource density in different water layers from 0 to 200 m. Furthermore, Generalized Additive Models (GAMs) were established for various water layers, combined with remote sensing data such as temperature (Temp), salinity (Sal), net primary productivity (Nppv), as well as latitude (Lat) and longitude (Lon) data, to analyze the influence of abiotic factors on abundance density of small pelagic fish species. The results showed that mean abundance and biomass densities estimated based on the acoustic method were 3.12×105±1.42×106 ind/n mile2 and 5768.39±26224.76 kg/n mile2, respectively. Small pelagic fish resources exhibited a predominant concentration within the 0–50 m layers and displayed a significant accumulation phenomenon near the Kuroshio Extension area in each water layer. The GAMs results indicated that abiotic factors affecting fish density vary across different water layers. Temp and Lon factors appeared in optimal GAMs for all water layers and significantly contributed to fish density. Variations in temperature lead to differences in the vertical distribution of fishery resources. Our results emphasized the necessity of exploring the relationship between abiotic factors and fish density within different water layers. This research can provide scientific support for developing and managing fishery resources in the Northwest Pacific Ocean.

Infection of guppies (Poecilia reticulata) with the Asian fish tapeworm Schyzocotyle acheilognathi in an urban stream in Brazil.

Schyzocotyle acheilognathi is a fish tapeworm native to Asia but has been reported as an alien species on practically all other continents. Its invasive potential is due to its low host specificity and high adaptability to different environments, and its spread to new areas can result in economic and ecological impacts. Studies reporting this species in South America are still scarce, indicating the need to monitor its dispersion to new areas. Herein, tapeworms found in guppies, Poecilia reticulata, from an urban stream located in Belo Horizonte, Minas Gerais, Brazil, in April 2021 were subjected to morphological and molecular characterization. As a result, 5/13 (38.5%) of the P. reticulata specimens evaluated were infected with intestinal tapeworms. It was verified a mean intensity of infection of 7.8 (1-25) and a mean abundance of infection of 3 (0-25). The morphology of the cestodes obtained was compatible with that of S. acheilognathi. Moreover, genetic analysis based on cytochrome c oxidase subunit 1 gene (Cox-1) revealed 97.89-99.77% similarity to isolates of this species from different localities. The possibility that S. acheilognathi is expanding to new regions of South America is discussed.

Sampling efficiency and screening of Aedes albopictus for yellow fever virus in Niger Delta region of Nigeria.

Aedes albopictus, like Aedes aegypti, is a virulent vector of arboviruses especially the well-documented spread of yellow fever around the world. Although yellow fever is prevalent in Nigeria, there is a paucity of information in the Niger Delta region on the distribution of Aedes mosquito vectors and molecular detection of the virus in infected mosquitoes. This study sampled Aedes mosquitoes around houses associated with farms from four communities (Otolokpo, Ute-Okpu, Umunede, and Ute Alohen) in Ika North-East Local Government Area of Delta State, Nigeria. various sampling methods were used in Aedes mosquito collection to test their efficacy in the survey. Mosquitoes in holding cages were killed by freezing and morphologically identified. A pool of 15 mosquitoes per Eppendorf tube was preserved in RNAi later for yellow fever virus screening. Two samples were molecularly screened for each location. seven hundred and twenty-five (725) mosquitoes were obtained from the various traps. The mean abundance of the mosquitoes was highest in m-HLC (42.9) compared to the mosquitoes sampled using other techniques (p<0.0001). The mean abundance of mosquitoes was lowest in Center for Disease Control (CDC) light traps without attractant (0.29). No yellow fever virus strain was detected in all the mosquitoes sampled at the four locations. this study suggests that Aedes albopictus are the mosquitoes commonly biting around houses associated with farms. More so, yellow fever virus was not detected in the mosquitoes probably due to the mass vaccination exercise that was carried out the previous year in the study area. More studies are required using the m-HLC to determine the infection rate in this endemic area.

A study of changes in nitrogen and phosphorus patterns and microplastic characteristics in sediment-water systems

Abstract The main objective of this study was to characterize the distribution of microplastics and nitrogen and phosphorus forms in the surface sediments of Lake Luoma, where samples were collected from August 2022 to March 2024 from 32 sampling sites. The enrichment factor method and pollution load index were used extensively to analyze the environmental characterization of heavy metals in Lake Luoma’s sediments. Shape differences were used to estimate individual particle volume and mass, and microplastic storage calculations per sediment were calculated by combining the percentage of microplastics in each shape. The results showed that the average ammonia nitrogen content in the water of Luoma Lake was 346.49 mg/kg, and the average nitrate nitrogen content was 9.75 mg/kg. Phosphorus was mostly present in the form of iron and phosphorus, with a detection rate of 85.67%. Most of the area’s nitrogen and phosphorus are in line with the Ⅲ water quality standard in the “Environmental Quality Standard for Surface Water”, but the total phosphorus content of individual sampling points is more than 0.1mg/L, which is more serious pollution. The mean abundance of microplastics in the sediments of Lake Luoma was 5506.45±2537.21 n·m−3 , showing the trend of in-lake &gt; confluent tributaries &gt; out-lake. Microplastics were released into the upstream surface sediments by the water flow, moved downstream, and settled again.

Diversity and Distribution of Avifauna in the Northeast of Addis Ababa, Central Ethiopia.

Exploring avian species diversity and distribution patterns is vigorous for conservation efforts in biodiversity-rich countries such as Ethiopia. Compared to other species, birds are relatively well-known and easily observed, making them great markers of productivity or biodiversity. Although bird species are found all across the world, their survival and range have been negatively impacted by habitat loss, fragmentation, and destruction. Thus, the goal of this study is to provide baseline data on avifaunal diversity in the Northeast of Addis Ababa, including species richness, distribution, and relative abundance in various habitats conducted from January 2023 to September 2023 using a stratified sampling design into three habitat types: settlement, farmland, and abattoir. A fixed-width line transect sampling method was used at the farmland and settlement, and a point transect was employed at the abattoir site to collect the bird data. The data were compared using Mann-Whitney and Kruskal-Wallis statistical tests in both seasons and habitat types. A total of 42 bird species belonging to twenty-three families, and nine orders were recorded during the study period. Of these, blue-winged goose and wattled ibis are endemic to Ethiopia. Hooded vultures and White-backed vultures are critically endangered species. The mean abundance of bird species significantly varied in the three habitat types (χ2 = 13.6, df = 2, p=0.001). The abundance of bird species was nonsignificant difference between wet and dry seasons (U = -0.874, p=0.381). The highest diversity (H' = 2.74) was recorded at settlement, and the lowest diversity index (H' = 1.09) was recorded at the abattoir in the dry season. In the wet season, the highest diversity (H' = 2.66) was recorded in the farmland, and the lowest (H' = 1.08) was recorded at the abattoir. The highest evenness (J = 0.94 and J = 0.93) was recorded on the farmland in the wet and dry seasons, respectively. In the study area, urbanization is extremely impacting the environment and altering ecosystem services upon which human civilization depends. Most of the avian species observed in the study area are capable and tolerant of human-induced habitats in the city. Therefore, city planners must consider conserving urban bird species' habitats and feeding sites.

Enhanced phylogenetic insights into the microbiome of chronic rhinosinusitis through the novel application of long read 16S rRNA gene amplicon sequencing.

16S rRNA next generation sequencing (NGS) has been the de facto standard of microbiome profiling. A limitation of this technology is the inability to accurately assign taxonomy to a species order. Long read 16S sequencing platforms, including Oxford Nanopore Technologies (ONT), have the potential to overcome this limitation. The paranasal sinuses are an ideal niche to apply this technology, being a low biomass environment where bacteria are implicated in disease propagation. Characterising the microbiome to a species order may offer new pathophysiological insights. Cohort series comparing ONT and NGS biological conclusions. Swabs obtained endoscopically from the middle meatus of 61 CRSwNP patients underwent DNA extraction, amplification and dual sequencing (Illumina Miseq (NGS) and ONT GridION). Agreement, relative abundance, prevalence, and culture correlations were compared. Mean microbiome agreement between sequencers was 61.4%. Mean abundance correlations were strongest at a familial/genus order and declined at a species order where NGS lacked resolution. The most significant discrepancies applied to Corynebacterium and Cutibacterium, which were estimated in lower abundance by ONT. ONT accurately identified 84.2% of cultured species, which was significantly higher than NGS. ONT demonstrated superior resolution and culture correlations to NGS, but underestimated core sinonasal taxa. Future application and optimisation of this technology can advance our understanding of the sinonasal microenvironment.

Amphibians of the genus Rana in the steppe zone of Ukraine: population status, distribution, and ecological features

Frogs of the genus Rana Linnaeus, 1758 are represented in the steppe zone of Ukraine by their southernmost populations. The distribution of brown frogs in the steppe zone of Ukraine is closely related to the floodplain forests of major rivers (Dnipro, Dnister, Danube, Southern Bug, Oril, Samara, Donets, etc.). The paper presents for the first time data on the distribution, ecological and population features, habitats, specifics of reproduction and development of brown frogs. New habitats of R. arvalis were found in the floodplain habitats of the lower reaches of the Dnipro River in Kherson Oblast and populations were confirmed in Dnipropetrovsk and Kirovohrad oblasts. The southern border is intrazonal. The new southernmost localities are described from Kherson Oblast (the villages of Pravi Solontsi and Krynky). The habitats belong to forest type habitats (G). The mean abundance of frogs is 5–10 individuals per 1 km of route and can reach 50 individuals per 10 m2 during the spawning season (Black Forest Reserve, Kirovohrad Oblast). The breeding season is in late March to early April at air temperatures of +3–4 to 8–12°C and water temperatures of +7–9°C. The mating process is short. The Dnipro isolates of R. arvalis may be of relict nature, form a series of refugia and be of important historical and indicator value. Given the overall reduction in the range of R. arvalis within its core area, active populations in the south can be valuable reserves for the conservation of the species and the sustainability of steppe biodiversity. Two other species, R. temporaria and R. dalmatina, were not found and their habitat within the steppe zone has not yet been confirmed. As typical forest species, they are common closer to the forest-steppe zone. Given the current state of brown frog populations in the steppe zone of Ukraine, their low numbers and isolation, they need regional protection along with their habitats. The issue of determining the origin of the identified populations in order to form an idea of the historical and genetic value of the southernmost populations of brown frogs in Ukraine remains promising.

Short term antibiotic effects on gut microbiome in Indian preschoolers: A 16S rRNA analysis

Objectives: Antibiotic use is associated with dysbiosis of the gut microbiome. The objective of this study is to investigate the effect of antibiotics on gut composition in children aged 3–5 years receiving antibiotics compared to children who did not receive antibiotics. Materials and Methods: A total of 54 participants aged 3–5 years were included in this multi-centric cohort study. Participants were divided into two equal groups, that is the treatment-experienced group (Group 1, n = 27, antibiotic) and the treatment-not-experienced group (Group 2, n = 27, non-antibiotic). Stool samples of study participants were collected on days 0 and 5 (± 1 day) and analyzed using 16Svedberg ribosomal ribonucleic acid (16S rRNA) gene sequencing. Statistical Analysis: The Kruskal-Wallis H-test and Benjamini-Hochberg FDR correction were applied to determine the differentially abundant pathways across the zones using Statistical Analysis of Metagenomic Profiles (STAMP) (v2.1.3). Results: A non-significant increase in the mean abundance of the Phyla Bacteroidota, Proteobacteria, Actinobacteria, and Verrucomicrobiota was observed in both groups from day 0 to day 5. An alteration in the Firmicutes/Bacteroidetes ratio was observed. A significant (P &lt; 0.05) abundance of genus Enterobacteriaceae, Enterococcaceae, and Lactobacillaceae was observed in the participants with antibiotic treatment. The relative abundance of families Enterococcus, Lactobacillus, Sellimonas, Ruminococcus, Torques, and Eggerthella groups was observed to be significantly higher (P &lt; 0.05) in participants with antibiotic treatment. Beta-diversity indices revealed significant differences at group and subgroup levels regarding the bacterial counts. Conclusions: It was observed that a short-term course of 5 days of antibiotic usage is associated with altered microbial abundance and diversity.

Assessing the Diversity of Metazoan Parasites of Sarotherodon melanotheron (Cichlidae) from Inlands Waters in Southern Benin (West Africa)

Aims: This paper presents a snapshot of the metazoan parasite fauna of Sarotherodon melanotheron collected from two stations across lake Nokoué.&#x0D; Study Design: Fish samplings were done at the landing stage of Lake Nokoué (sampling site 1) and Tota (sampling site 2) from october 2016 to march 2017. Water physicochemical parameters such as pH, salinity, temperature, and conductivity were measured monthly. &#x0D; Methodology: A total of 246 specimens of Sarotherodon melanotheron comprising 149 males and 97 females were investigated. Size and weight were measured. Then,fish were dissected and parasites were checked in several organs. Collected parasite were identified using adequate keys of identification. The chi square test was used to compare the prevalence of different parasite groups whereas Student T-test was applied to assess difference between parasite mean abundance within the two sampling stations. The pearson correlation coefficient was used to appraise possible influence of water parameters on parasite prevalence.&#x0D; Results: The total prevalence was 86.58%. Eight parasite species were collected belonging to Myxosporidia, Monogena, Digena, Cestoda, Acanthocephala and Copepoda. Epidemiological parameters were calculated in order to appreciate the diversity of the parasitofauna according to sampling site, sex, and fish size. Females were significantly more infected than males (χ2 = 10.093; p &lt; .05). Among the parasites, only monogenean prevalence (41.46%) was significantly different (χ2 = 149.645; p &lt; .05). Correlation between physicochemical parameters and the prevalence of parasite groups showed that monogenea and cestoda were the most abundant in rainy season in opposite to the Digena that are mainly recorded in the dry season.

Coma Abundances of Volatiles at Small Heliocentric Distances: Compositional Measurements of Long-period Comet C/2020 S3 (Erasmus)

We report production rates of H2O and nine trace molecules (C2H6, CH4, H2CO, CH3OH, HCN, NH3, C2H2, OCS, and CO) in long-period comet C/2020 S3 (Erasmus) using the high-resolution, cross-dispersed infrared spectrograph (iSHELL) at the NASA Infrared Telescope Facility, on two pre-perihelion dates at heliocentric distances R h = 0.49 and 0.52 au. Our molecular abundances with respect to simultaneously or contemporaneously measured H2O indicate that S3 is depleted in CH3OH compared to its mean abundance relative to H2O among the overall comet population (Oort Cloud comets and Jupiter-family comets combined), whereas the eight other measured species have near-average abundances relative to H2O. In addition, compared to comets observed at R h < 0.80 au at near-infrared wavelengths, S3 showed enhancement in the abundances of volatile species H2CO, NH3, and C2H2, indicating possible additional (distributed) sources in the coma for these volatile species. The spatial profiles of volatile species in S3 in different instrumental settings are dramatically different, which might suggest temporal variability in comet outgassing behavior between the nonsimultaneous measurements. The spatial distributions of simultaneously measured volatile species C2H6 and CH4 are nearly symmetric and closely track each other, while those of CO and HCN co-measured with H2O (using different instrument settings) are similar to each other and are asymmetric in the antisunward direction.

Multivariate study of lice (Insecta: Psocodea: Phthiraptera) assemblages hosted by hummingbirds (Aves: Trochilidae).

Lice were collected from 579 hummingbirds, representing 49 species, in 19 locations in Brazil, Costa Rica, Honduras, Paraguay and Peru, at elevations 0–3000 m above sea level. The following variables were included in an ecological analysis (1) host species' mean body mass, sexual size dimorphism, sexual dichromatism, migratory behaviour and dominance behaviour; (2) mean elevation, mean and predictability of temperature, mean and predictability of precipitation of the host species' geographic area; (3) prevalence and mean abundance of species of lice as measures of infestation. Ordination methods were applied to evaluate data structure. Since the traits are expressed at different scales (nominal, interval and ratio), a principal component analysis based on d-correlations for the traits and a principal coordinates analysis based on the Gower index for species were applied. Lice or louse eggs were found on 80 (13.8%) birds of 22 species. A total of 267 lice of 4 genera, Trochiloecetes, Trochiliphagus, Myrsidea and Leremenopon, were collected, with a total mean intensity of 4.6. There were positive interactions between migration behaviour and infestation indices, with elevational migrants having a higher prevalence and abundance of lice than resident birds. Further, we found weak negative correlations between host body mass and infestation indices and positive correlations between mean elevation and prevalence and abundance of Trochiliphagus. Thus, formerly unknown differences in the ecological characteristics and infestation measures of Trochiliphagus and Trochiloecetes lice were revealed, which allows a better understanding of these associations and their potential impacts on hummingbirds.

Microplastics and other anthropogenic fibres in large apex shark species: Abundance, characteristics, and recommendations for future research

Microplastics and microfibres are found ubiquitously in global oceans as well as marine organisms from different trophic levels. However, little is known about the presence of microplastics and microfibres in marine megafauna, such as sharks. This study provided the first investigation of the presence of microplastics and other anthropogenic fibres (i.e., cellulose based fibres) in intestine and muscle samples of four large apex shark species in Australian coastal waters. Microplastics and other anthropogenic fibres were found in 82% of the analysed intestine samples. The mean abundance in intestine samples was 3.1 ± 2.6 particles/individual, which corresponded to 0.03 ± 0.02 particles/g of intestine, across all shark species. The size of particles ranged from 190 to 4860 μm in length with 92% being fibrous in shape and the rest fragments. FTIR spectroscopy identified that 70% of fibres were cellulose-based followed by polyethylene terephthalate (PET), while the fragments were polyethylene and polypropylene. In shark muscles, 60% of samples contained microplastics and other anthropogenic fibres, again with the majority being cellulose-based fibres followed by PET fibres. Methodological differences hinder a more comprehensive assessment of microplastic contamination across studies. Additionally, we identified some challenges which should be factored in for future studies looking at the presence of microplastics as well as other anthropogenic fibres in these large marine organisms. Overall, the findings provide first evidence of microplastics and other anthropogenic fibres not only in the intestines, but also in muscle tissues of large apex shark species.