Trophic niche of Australian cownose rays (Rhinoptera neglecta) and whitespotted eagle rays (Aetobatus ocellatus) along the east coast of Australia.
Ontology highlight
ABSTRACT:
SUBMITTER: Chan AJ
PROVIDER: S-EPMC9310580 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BackgroundAnimal-associated microbiomes can be influenced by both host and environmental factors. Comparing wild animals to those in zoos or aquariums can help disentangle the effects of host versus environmental factors, while also testing whether managed conditions foster a 'natural' host microbiome. Focusing on an endangered elasmobranch species-the whitespotted eagle ray Aetobatus narinari-we compared the skin, gill, and cloaca microbiomes of wild individuals to those at Georgia Aquarium. Whitespotted eagle ray microbiomes from Georgia Aquarium were also compared to those of cownose rays (Rhinoptera bonasus) in the same exhibit, allowing us to explore the effect of host identity on the ray microbiome.ResultsLong-term veterinary monitoring indicated that the rays in managed care did not have a history of disease and maintained health parameters consistent with those of wild individuals, with one exception. Aquarium whitespotted eagle rays were regularly treated to control parasite loads, but the effects on animal health were subclinical. Microbiome α- and β-diversity differed between wild versus aquarium whitespotted eagle rays at all body sites, with α-diversity significantly higher in wild individuals. β-diversity differences in wild versus aquarium whitespotted eagle rays were greater for skin and gill microbiomes compared to those of the cloaca. At each body site, we also detected microbial taxa shared between wild and aquarium eagle rays. Additionally, the cloaca, skin, and gill microbiomes of aquarium eagle rays differed from those of cownose rays in the same exhibit. Potentially pathogenic bacteria were at low abundance in all wild and aquarium rays.ConclusionFor whitespotted eagle rays, managed care was associated with a microbiome differing significantly from that of wild individuals. These differences were not absolute, as the microbiome of aquarium rays shared members with that of wild counterparts and was distinct from that of a cohabitating ray species. Eagle rays under managed care appear healthy, suggesting that their microbiomes are not associated with compromised host health. However, the ray microbiome is dynamic, differing with both environmental factors and host identity. Monitoring of aquarium ray microbiomes over time may identify taxonomic patterns that co-vary with host health.
| S-EPMC9128078 | biostudies-literature
Project description:Suicide is an increasing global concern with multiple risk factors, yet location-based understanding is limited. In Australia, surf lifesavers (SLS) and lifeguards patrol the coast, performing rescues and assisting injured people, including people who suicide. This study is a descriptive epidemiological analysis of Australian coastal suicide deaths. The results will be used to inform training and support surf lifesaving personnel and suicide prevention organisations. This is a population-based cross-sectional study of suicide deaths at Australian coastal locations (between 1 January 2005 and 31 December 2019). Data were sourced from the National Coronial Information System and SLS Australia's Incident Report Database. Analyses explored decedent, incident, and risk factors by sex and method. Across the study period, there were 666 coastal suicide deaths (71.0% male, 43.4% jumping from high places [X80]). Males were more likely to suicide by other means (hanging, self-poisoning, firearm discharge; n = 145, 83.8%), compared to females who were more likely to suicide by drowning ([X71]; n = 77, 37.7%). In one third (n = 225, 38.3%) toxicology was a contributing factor. The risk of coastal suicides was 10.3 times higher during the seven-days prior to their birthday (p<0.001). Evidence of mental ill health was reported in 61.4% (n = 409) of cases and evidence of suicidal behaviour was reported for 37.4% of decedents (n = 249), more prevalent in females. SLS responded in 10.7% (n = 71) of coastal suicides (most jumps from high places; n = 36, 50.7%). Coastal suicides differ to national trends suggesting that location-based differences should be considered during development of preventative and protective measures, especially at a community level. Accessibility, availability, perceived lethality and symbolic qualities are proposed to influence suicide location decisions. These results will guide support and education strategies for surf lifesaving personnel, contributes to established, ongoing suicide surveillance efforts (including hot-spot identification) and add to the limited literature exploring place-based suicide.
| S-EPMC8136651 | biostudies-literature
Project description:The efficacy of fisheries management strategies depends on stock assessment and management actions being carried out at appropriate spatial scales. This requires understanding of spatial and temporal population structure and connectivity, which is challenging in weakly structured and highly connected marine populations. We carried out a population genomics study of the heavily exploited snapper (Chrysophrys auratus) along ~2600 km of the Australian coastline, with a focus on Western Australia (WA). We used 10,903 filtered SNPs in 341 individuals from eight sampling locations to characterize population structure and connectivity in snapper across WA and to assess if current spatial scales of stock assessment and management agree with evidence from population genomics. Our dataset also enabled us to investigate temporal stability in population structure as well as connectivity between WA and its nearest, eastern jurisdictional neighbour. As expected for a species influenced by the extensive ocean boundary current in the region, low genetic differentiation and high connectivity were uncovered across WA. However, we did detect strong isolation by distance and genetic discontinuities in the mid-west and south-east. The discontinuities correlate with boundaries between biogeographic regions, influenced by on-shelf oceanography, and the sites of important spawning aggregations. We also detected temporal instability in genetic structure at one of our sites, possibly due to interannual variability in recruitment in adjacent regions. Our results partly contrast with the current spatial management of snapper in WA, indicating the likely benefits of a review. This study supports the value of population genomic surveys in informing the management of weakly structured and wide-ranging marine fishery resources.
| S-EPMC9309437 | biostudies-literature
Project description:It is deemed important to understand cetacean occurrence and distribution to comprehend their ecological roles. The geographical occurrence of species' niche can be used to better describe their potential distribution. The niche can be defined using environmental variables. Those variables are considered static and not affected by biological activities. The present study goal was to assess the occurrence and distribution of cetaceans along the southeastern Brazilian coast, as well as to define the fundamental and realized niche of each species and to investigate niche overlap at local scale. The environmental requirements for each species were also investigated throughout statistical tests. Sighting data were obtained through oceanographic surveys conducted between 2012 and 2015. The environmental variables available on MARSPEC and the software NicheA were used for the ecological niche modeling. A total of twelve cetacean species were identified and the potential distribution areas of the six commonest ones were defined. Even though the species presented different environmental preferences, most of them had partial overlap among niches and potential distribution areas. The environmental heterogeneity of the study area might support the co-occurrence of different species with different environmental requirements.
| S-EPMC7543724 | biostudies-literature
Project description:Hette-Tronquart (2019, Ecol. Lett.) raises three concerns about our interpretation of stable isotope data in Sheppard et al. (2018, Ecol. Lett., 21, 665). We feel that these concerns are based on comparisons that are unreasonable or ignore the ecological context from which the data were collected. Stable isotope ratios provide a quantitative indication of, rather than being exactly equivalent to, trophic niche.
| S-EPMC6851704 | biostudies-literature
Project description:Generalist species commonly have a fundamental role in ecosystems as they can integrate spatially distinct habitats and food-web compartments, as well as control the composition, abundance and behavior of organisms at different trophic levels. Generalist populations typically consist of specialized individuals, but the potential for and hence degree of individual niche variation can be largely determined by habitat complexity. We compared individual niche variation within three generalist fishes between two comparable lakes in the Czech Republic differing in macrophyte cover, i.e. macrophyte-rich Milada and macrophyte-poor Most. We tested the hypothesis that large individual niche variation among generalist fishes is facilitated by the presence of macrophytes, which provides niches and predation shelter for fish and their prey items. Based on results from stable nitrogen (δ15N) and carbon (δ13C) isotopic mixing models, perch (Perca fluviatilis L.) and rudd (Scardinius erythrophthalmus (L.)) showed larger individual variation (i.e., variance) in trophic position in Milada as compared to Most, whereas no significant between-lake differences were observed for roach (Rutilus rutilus (L.)). Contrary to our hypothesis, all the three species showed significantly lower individual variation in the relative reliance on littoral food resources in Milada than in Most. Rudd relied significantly more whereas perch and roach relied less on littoral food resources in Milada than in Most, likely due to prevalent herbivory by rudd and prevalent zooplanktivory by perch and roach in the macrophyte-rich Milada as compared to macrophyte-poor Most. Our study demonstrates how the succession of macrophyte vegetation, via its effects on the physical and biological complexity of the littoral zone and on the availability of small prey fish and zooplankton, can strongly influence individual niche variation among generalist fishes with different ontogenetic trajectories, and hence the overall food-web structures in lake ecosystems.
| S-EPMC5423621 | biostudies-literature
Project description:The trophic niche is a life trait that identifies the consumer's position in a local food web. Several factors, such as ontogeny, competitive ability and resource availability contribute in shaping species trophic niches. To date, information on the diet of European Hydromantes salamanders are only available for a limited number of species, no dietary studies have involved more than one species of the genus at a time, and there are limited evidences on how multiple factors interact in determining diet variation. In this study we examined the diet of multiple populations of six out of the eight European cave salamanders, providing the first data on the diet for five of them. In addition, we assessed whether these closely related generalist species show similar diet and, for each species, we tested whether season, age class or sex influence the number and the type of prey consumed. Stomach condition (empty/full) and the number of prey consumed were strongly related to seasonality and to the activity level of individuals. Empty stomachs were more frequent in autumn, in individuals far from cave entrance and in juveniles. Diet composition was significantly different among species. Hydromantes imperialis and H. supramontis were the most generalist species; H. flavus and H. sarrabusensis fed mostly on Hymenoptera and Coleoptera Staphylinidae, while H. genei and H. ambrosii mostly consumed Arachnida and Endopterygota larvae. Furthermore, we detected seasonal shifts of diet in the majority of the species examined. Conversely, within each species, we did not find diet differences between females, males and juveniles. Although being assumed to have very similar dietary habits, here Hydromantes species were shown to be characterized by a high divergence in diet composition and in the stomach condition of individuals.
| S-EPMC6193653 | biostudies-literature
Project description:Small-scale fisheries of the Brazilian Atlantic Forest Coast (BAFC) depend on fish resources for food and income. Thus, if the catch diminishes or if fish species that are a target for fishers are overexploited or impacted, this could affect fishers' livelihoods. The exclusion of threatened fish species from the catch is believed to be a threat to small-scale fisheries, which is likely to be the case along the BAFC. Many fish species are currently listed as threatened or vulnerable, whereas there is not enough biological information available to determine the status of the majority of the other species. Failure to protect the BAFC biodiversity might negatively impact fishers' income and the regional economy of local small-scale fisheries. We collected data from 1986 to 2009 through 347 interviews and 24-h food recall surveys at seven southeastern coastal sites of the Atlantic Forest. We show that important species of consumed fish are currently threatened: of the 65 species mentioned by fishers as the most consumed fishes, 33% are decreasing and 54% have an unknown status. Thus, biological and ecological data for BAFC marine species are urgently needed, along with co-management, to promote fish conservation.
| S-EPMC5639802 | biostudies-other
Project description:Human presence and activity in tropical forest is thought to exert top-down regulation over the various 'green-world' pathways of plant-based foodwebs. However, these effects have never been explored for the 'brown-world' pathways of fecal-detritus webs. The strong effects of humans on tropical game mammals are likely to indirectly influence fecal detritivores (including Scarabaeine dung beetles), with subsequent indirect impacts on detrivore-mediated and plant-facilitating detrital processes. Across a 380-km gradient of human influence in the western Brazilian Amazon, we conducted the first landscape-level assessment of human-induced cascade effects on the fecal detritus pathway, by coupling data on human impact, game mammal and detritivore community structure, and rate measurements of a key detritus process (i.e. dung beetle-mediated secondary seed dispersal). We found evidence that human impact indirectly influences both the diversity and biomass of fecal detritivores, but not detritivore-mediated processes. Cascade strength varied across detritivore groups defined by species' traits. We found smaller-bodied dung beetles were at higher risk of local decline in areas of human presence, and that body size was a better predictor of cascade structure than fecal resource manipulation strategy. Cascade strength was also stronger in upland, unflooded forests, than in seasonally flooded forests. Our results suggest that the impact of human activity in tropical forest on fecal-detritus food web structure is mediated by both species' traits and habitat type. Further research will be required to determine the conditions under which these cascade effects influence fecal-detritus web function.
| S-EPMC3797778 | biostudies-literature
Project description:The genus Kogia, which comprises only two extant species, Kogia sima and Kogia breviceps, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution) have been confirmed to pose a particular threat to the Kogia species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST), water depth, and chlorophyll-a, correlate to Kogia stranding events along the Brazilian coast. The results of our statistical analyses suggest that K. sima is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, K. breviceps appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting Kogia strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both Kogia species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of Kogia stranding data in relation to environmental conditions along the Brazilian coast.
| S-EPMC4701718 | biostudies-literature