scholarly journals Seasonal variability in the diet of juvenile European catfish, Silurus glanis, in the Arno River (Italy) in Florence

2021 ◽  
Vol 29 (1) ◽  
pp. 54-61
Author(s):  
Phillip J. Haubrock
Keyword(s):  
Invasive Species ◽  
Seasonal Variability ◽  
Life Stage ◽  
Ecological Impact ◽  
Biotic Interactions ◽  
Feeding Preferences ◽  
Silurus Glanis ◽  
European Catfish ◽  
The Impact ◽  
Impact Predictions

Abstract While approaches for assessing the impact of invasive species are advancing, fundamental autoecological information such as feeding preferences is often unavailable for many invasive species. The European catfish, Silurus glanis, is a well-known, high-impact invasive predator; however, there remain considerable gaps in knowledge about its feeding preferences and biotic interactions that limit ecological impact predictions for this predator. This study is an investigation of seasonal variability in this predator’s diet during the juvenile life stage using the Arno River, Italy as a model system. This study identified significant differences across seasons, provided further information on the dietary spectrum of this species, and raised important questions for further study.

scholarly journals The Influence of Feeding Level on Growth Performances of European Catfish (Silurus glanis L., 1758) Juveniles under Recirculating Water Conditions

2019 ◽  
Vol 76 (2) ◽  
pp. 109
Author(s):  
Iulia GRECU ◽  
Lorena DEDIU ◽  
Angelica DOCAN ◽  
Victor CRISTEA
Keyword(s):  
Life Stage ◽  
Size Variation ◽  
The Body ◽  
Feed Conversion ◽  
Silurus Glanis ◽  
Feeding Level ◽  
Growth Performances ◽  
Mean Size ◽  
Good Potential ◽  
The Impact

The study was carried out with one summer-old Silurus glanis juveniles, having the mean size 23.04±2.05 cm and weight 73.84±19.12 g, reared in recirculating water condition, in order to assess the impact of feeding level on growth performances and body size variation of fish. Two feeding levels were tested (R1=1.5% BW/day and R2=2.5% BW/day), in duplicate, during 6 weeks, and the biomass gain (BG), feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), morphometric relationship between length-weight (LWR) and coefficient of variation (CV) were assessed. Data revealed that the overall mean weight of the biomass was doubled during the trial, from 14.92 kg to 31.17 kg, and the body growth significantly increases with the increment of the feeding rate (13.48 kg in R1 and 17.70 kg in R2), underlying the good potential of the species, at this life stage, for fast-growing under intense conditions. The calculated SGR in R1 was 1.43%/day and in R2, significantly higher, as 2.05 %/day, for the almost similar values of FCR (0.74 g/g) and PER (2.50 g/g) recorded between the treatments.

scholarly journals Habitat formed by the invasive macroalga Caulerpa filiformis (Suhr) Hering (Caulerpales, Chlorophyta) alters benthic macroinvertebrate assemblages in Peru

2021 ◽  
Author(s):  
Silvia Aguilar ◽  
Pippa J. Moore ◽  
Roberto A. Uribe
Keyword(s):  
Invasive Species ◽  
Benthic Macroinvertebrates ◽  
Ecological Impact ◽  
Ecological Impacts ◽  
Benthic Macroinvertebrate ◽  
Soft Sediment ◽  
Taxonomic Richness ◽  
Macroinvertebrate Assemblages ◽  
Peruvian Coast ◽  
The Impact

Abstract The green macroalga Caulerpa filiformis has been spreading on shallow soft sediment habitats along the Peruvian coast, colonizing previously unvegetated sediments to create monospecific meadows. We examined the nature of the impact of C. filiformis meadows on the density, taxonomic richness and assemblage structure of epifaunal and infaunal benthic macroinvertebrates. Specifically, we tested whether the spread of C. filiformis has resulted in different macroinvertebrate assemblages than those formed by the dominant native macroalgae (i.e., Rhodymenia spp.) and unvegetated sediments. Surveys were undertaken in two bays in each of two locations, in central and southern Peru, during winter 2017 and summer 2018. In general, our results show that macroinvertebrate assemblages were similar across all three habitats, although there were some differences, related to location and season, but with no clear patterns observed. Taxonomic richness and density was generally higher in the vegetated habitats than the unvegetated habitat, and where there were differences between the two vegetated habitats there was no consistent pattern of which habitat supported the highest richness or density. Given invading C. filiformis is primarily colonizing unvegetated habitats it would appear that this species is creating a new niche which supports similar assemblages, but higher taxonomic richness and density than unvegetated habitats. While our study suggests that C. filiformis is having a limited ecological impact we recommend that actions be put in place to limit the spread of this invasive species at the same time as increasing monitoring of the ecological impacts of this species as lags in the ecological impacts of invasive species are common.

High predatory efficiency and abundance drive expected ecological impacts of a marine invasive fish

2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
Ecological Impact ◽  
Marine Species ◽  
Ecological Impacts ◽  
Negative Effects ◽  
Marine Predator ◽  
Eastern Gulf Of Mexico ◽  
Red Grouper ◽  
Per Capita

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.

scholarly journals Ontogenetic shift in the trophic role of the invasive killer shrimp Dikerogammarus villosus: a stable isotope study

2021 ◽  
Author(s):  
Francesco Mancini ◽  
Raffaele De Giorgi ◽  
Alessandro Ludovisi ◽  
Salvatrice Vizzini ◽  
Giorgio Mancinelli
Keyword(s):  
Dietary Habits ◽  
Trophic Position ◽  
Ecological Impact ◽  
Central Italy ◽  
Local Conditions ◽  
Dikerogammarus Villosus ◽  
Isotopic Signatures ◽  
Depth Analysis ◽  
Stable Isotope Study ◽  
The Impact

AbstractThe introduction of the amphipod Dikerogammarus villosus in European fresh waters is to date recognized as a threat to the integrity of invaded communities. Predation by D. villosus on native benthic invertebrates is assumed as the key determinant of its ecological impact, yet available information describe the species as a primary consumer as well as a carnivore depending on local conditions. Here, we assessed the trophic position (TP) of D. villosus in Lake Trasimeno, a recently invaded lentic system in central Italy, using the CN isotopic signatures of individuals captured in winter spanning two orders of magnitude in body size. TP estimations were compared with those characterizing the native amphipod Echinogammarus veneris and other representative invertebrate predators. On average, D. villosus showed a trophic position higher than E. veneris, and comparable with that of odonate nymphs. An in-depth analysis revealed that large-sized individuals had a trophic position of 3.07, higher than odonates and close to that of the hirudinean predator Erpobdella octoculata, while small-sized specimens had a trophic position of 2.57, similar to that of E. veneris (2.41). These findings indicate that size-related ontogenetic shifts in dietary habits may per se vary the nature of the interaction between Dikerogammarus villosus and native invertebrates from competition to predation. Information collated from published isotopic studies corroborated the generality of our results. We conclude that intra-specific trophic flexibility may potentially amplify and make more multifaceted the impact of the species on other invertebrate species in invaded food webs.

scholarly journals Measuring capability wellbeing in adults at different stages of life for use in economic evaluation of health and care interventions: a qualitative investigation in people requiring kidney care

2021 ◽  
Author(s):  
Paul Mark Mitchell ◽  
Samantha Husbands ◽  
Sabina Sanghera ◽  
Fergus John Caskey ◽  
Jemima Scott ◽  
...  
Keyword(s):  
Life Stage ◽  
Structured Interview ◽  
Health Conditions ◽  
Economic Evaluations ◽  
Qualitative Investigation ◽  
Key Factors ◽  
Younger Adults ◽  
Patient Groups ◽  
The Life Course ◽  
The Impact

Abstract Purpose Capability wellbeing measures, such as the ICECAP measures, have been proposed for use in economic evaluations to capture broader outcomes of health and care interventions. The ICECAP measures have been developed to reflect capabilities at different stages of life. Some patient groups include patients of different ages and at different stages of life, so it is not always apparent which ICECAP measure is most relevant. This study explores the impact of age and life stage on completion, where both ICECAP-A and ICECAP-O were completed by the same patient. Methods A think-aloud study, and an associated semi-structured interview were conducted with people receiving kidney care as a renal outpatient, kidney transplant outpatient, or through receiving facility-based haemodialysis. Qualitative analysis focused on (1) differences in responses across measures by individuals, where attributes had conceptual overlap, (2) key factors in self-reported capability levels, and (3) measure preference. Results Thirty participants were included in the study, with a mix of older and younger adults. Attributes with similar wording across measures produced similar responses compared to attributes where wording differed. Age and health were key factors for self-reported capability levels. ICECAP-A was slightly preferred overall, including by older adults. Conclusion This study suggests use of ICECAP-A in patients with certain chronic health conditions that include a mix of adults across the life course. This study highlights the importance of considering the stage of life when using capability measures and in economic evaluations of health and care interventions more generally.

scholarly journals Seasonal variability of SST fronts and winds on the southeastern continental shelf of Brazil

2019 ◽  
Vol 69 (11-12) ◽  
pp. 1387-1399 ◽  
Author(s):  
Huan-Huan Chen ◽  
Yiquan Qi ◽  
Yuntao Wang ◽  
Fei Chai
Keyword(s):  
Continental Shelf ◽  
Wind Stress ◽  
Seasonal Variability ◽  
Detection Algorithm ◽  
Coupling Coefficients ◽  
Seafloor Topography ◽  
Wind Stress Curl ◽  
Large Coupling ◽  
The Impact ◽  
Sst Fronts

Abstract Fourteen years (September 2002 to August 2016) of high-resolution satellite observations of sea surface temperature (SST) data are used to describe the frontal pattern and frontogenesis on the southeastern continental shelf of Brazil. The daily SST fronts are obtained using an edge-detection algorithm, and the monthly frontal probability (FP) is subsequently calculated. High SST FPs are mainly distributed along the coast and decrease with distance from the coastline. The results from empirical orthogonal function (EOF) decompositions reveal strong seasonal variability of the coastal SST FP with maximum (minimum) in the astral summer (winter). Wind plays an important role in driving the frontal activities, and high FPs are accompanied by strong alongshore wind stress and wind stress curl. This is particularly true during the summer, when the total transport induced by the alongshore component of upwelling-favorable winds and the wind stress curl reaches the annual maximum. The fronts are influenced by multiple factors other than wind forcing, such as the orientation of the coastline, the seafloor topography, and the meandering of the Brazil Current. As a result, there is a slight difference between the seasonality of the SST fronts and the wind, and their relationship was varying with spatial locations. The impact of the air-sea interaction is further investigated in the frontal zone, and large coupling coefficients are found between the crosswind (downwind) SST gradients and the wind stress curl (divergence). The analysis of the SST fronts and wind leads to a better understanding of the dynamics and frontogenesis off the southeastern continental shelf of Brazil, and the results can be used to further understand the air-sea coupling process at regional level.

scholarly journals Temperature rise and parasitic infection interact to increase the impact of an invasive species

2017 ◽  
Vol 47 (5) ◽  
pp. 291-296 ◽  
Author(s):  
Ciaran Laverty ◽  
David Brenner ◽  
Christopher McIlwaine ◽  
Jack J. Lennon ◽  
Jaimie T.A. Dick ◽  
...  
Keyword(s):  
Invasive Species ◽  
Temperature Rise ◽  
Parasitic Infection ◽  
The Impact

A New Integrated Grey Water Footprint Assessment Method

2015 ◽  
Vol 671 ◽  
pp. 412-418
Author(s):  
Lu Lu Xu ◽  
Li Zhu Chen ◽  
Hugh Gong ◽  
Xue Mei Ding
Keyword(s):  
Water Footprint ◽  
Ecological Impact ◽  
Water Environment ◽  
Assessment Method ◽  
Water Volume ◽  
Accurate Assessment ◽  
Ambient Water ◽  
Grey Water ◽  
The Impact ◽  
Comprehensive Indicator

Water footprint is a volumetric indicator of freshwater appropriation. The grey water footprint (GWF) provides a tool to assess the water volume needed to assimilate a pollutant. However, evaluating the impact on water environment cannot rely solely on volumetric consumption of freshwater. It demands accurate assessment criteria to reflect its environmental and ecological effects on ambient water resource. In this paper, a new assessment method is proposed: the effluent toxicity and the Potential Eco-toxic Effects Probe (PEEP) index of aquatic environment are taken into consideration. This method provides a comprehensive indicator for evaluating water footprint, specified in effluents’ ecological impact on ambient water sources.

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