Seasonal patterns in trap catches of the crayfish Cambarus bartoni and Orconectes virilis in six south-central Ontario lakes

1993 ◽  
Vol 71 (6) ◽  
pp. 1136-1145 ◽  
Author(s):  
Keith M. Somers ◽  
Roger H. Green
Keyword(s):  
Water Temperature ◽  
Relative Abundance ◽  
Sampling Period ◽  
Smallmouth Bass ◽  
Orconectes Virilis ◽  
Scuba Divers ◽  
South Central ◽  
Baited Traps ◽  
Trap Catches ◽  
Physical And Chemical

Crayfish were trapped in six south-central Ontario lakes to examine seasonal changes in estimates of relative abundance. Baited-trap catches of Cambarus bartoni and Orconectes virilis correlated with changes in water temperature. Cambarid catches increased in the spring until a midsummer maximum, but dropped suddenly as the water temperature began to fall in August. Ovigerous (i.e., egg-bearing) females and recently moulted males were captured by SCUBA divers in August. Trap catches increased, once breeding and moulting periods concluded, and subsequently decreased as water temperatures continued to drop in the autumn. In contrast, catches of male O. virilis increased in the spring and remained relatively constant throughout the summer until water temperatures fell in September. Catches of female O. virilis peaked somewhat later in the summer and then gradually declined in the early fall. Although the two species and the two sexes differed in the length of the midsummer sampling period when trap catches were relatively constant, similar seasonal trends among lakes suggest that midsummer trap catches can be used to estimate crayfish relative abundance. Other factors, such as the presence of smallmouth bass (Micropterus dolomieui), lake physical and chemical characteristics, and the number of co-occurring crayfish species also correlated with trap catches. Both the presence of bass and the number of co-occurring species of crayfish probably affect crayfish behaviour and activity, thereby reducing catches in baited traps, but not necessarily affecting actual population abundance. Comparisons of relative abundance based on catches from baited traps must control for these seasonal behavioural, and environmental factors.

scholarly journals Mollusks (Gastropoda and Bivalvia) of the Multiple-Use Reserve Martín García Island, Río de la Plata River: biodiversity and ecology

2012 ◽  
Vol 72 (1) ◽  
pp. 121-130 ◽  
Author(s):  
II César ◽  
SM Martín ◽  
A Rumi ◽  
M Tassara
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Environmental Variables ◽  
Sampling Period ◽  
Pomacea Canaliculata ◽  
Rio De La Plata ◽  
Multiple Use ◽  
Río De La Plata ◽  
Oxygen Conductivity ◽  
La Plata

The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila , B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma, Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds.

scholarly journals Faecal bacterial composition in horses with and without free faecal liquid: a case control study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katrin M. Lindroth ◽  
Johan Dicksved ◽  
Erik Pelve ◽  
Viveca Båverud ◽  
Cecilia E. Müller
Keyword(s):  
Relative Abundance ◽  
Case Control Study ◽  
Sampling Period ◽  
Rrna Gene ◽  
Bacterial Composition ◽  
Clostridioides Difficile ◽  
Liquid Phases ◽  
And Control ◽  
The 16S Rrna Gene ◽  
Control Study

AbstractFree faecal liquid (FFL) is a condition in horses which manifests as differential defecation of solid and liquid phases of faeces. The etiology of FFL is currently unknown, but deviances in the hindgut microbiota has been suggested to be of importance. The present study aimed to compare the faecal bacterial composition of farm-matched horses with (case, n = 50) and without (control, n = 50) FFL. Samples were collected at three different occasions. The V3 and V4 regions of the 16S rRNA gene were amplified and sequenced using Illumina sequencing. Also, samples were cultivated for detection of Clostridioides difficile and Clostridium perfringens. Analysis revealed similar faecal bacterial composition between case and control horses, but an effect of sampling period (p = 0.0001). Within sampling periods, 14 genera were present in higher or lower proportions in case compared to control horses in at least one sampling period. Compared to controls, case horses had higher relative abundance of Alloprevotella (adjusted p < 0.04) and lower relative abundance of Bacillus spp. (adjusted p < 0.03) in at least two sampling periods. All horses tested negative for C. difficile and C. perfringens by culture of faeces. Further studies are required to establish the clinical relevance of specific bacterial taxa in FFL.

Response of benthic macroinvertebrate communities to El Niño related drought events in six upland streams in south-central Ontario

2008 ◽  
Vol 65 (5) ◽  
pp. 890-905 ◽  
Author(s):  
Beth Gilbert ◽  
Peter J Dillon ◽  
Keith M Somers ◽  
Ron A Reid ◽  
Lem Scott
Keyword(s):  
Relative Abundance ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Benthic Macroinvertebrate ◽  
Macroinvertebrate Communities ◽  
South Central ◽  
Effects Of Drought ◽  
One Year ◽  
The Impact

We examined the effects of extreme drought events on benthic macroinvertebrate (BMI) community structure in six forested upland streams in south-central Ontario, Canada, during a 9-year period. Variation in the mean winter El Niño – Southern Oscillation Index was strongly correlated with drought conditions (zero flow days) in the study streams. Drought onset and duration varied among study streams and among years. Below-average precipitation coincided with the occurrence of drought, although it remains unclear if snowfall and rainfall contributed equally to the impact of decreased precipitation. Increased relative abundance of Ephemeroptera, Plecoptera, and Trichoptera (EPT) one year following drought and decreased relative abundance two years after drought indicated high resistance but poor resilience. In contrast, chironomids showed poor resistance and high resilience. Although these patterns were not consistent across all streams, temporal coherence among streams was found in percent EPT, percent chironomids, and percent dipterans, suggesting that drought acts as a disturbance mechanism that simplifies benthos community assemblages. Biocriteria developed from 22 nearby reference streams indicated that abnormal BMI communities occurred only after recurring episodes of drought, indicating that the effects of drought are cumulative. Headwater streams may prove to be sentinel ecosystems for monitoring the impacts of climate change.

scholarly journals Olfactory Preference of Drosophila suzukii Shifts between Fruit and Fermentation Cues over the Season: Effects of Physiological Status

Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 200 ◽  
Author(s):  
Rik Clymans ◽  
Vincent Van Kerckvoorde ◽  
Eva Bangels ◽  
Wannes Akkermans ◽  
Ammar Alhmedi ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Physiological Status ◽  
Drosophila Suzukii ◽  
Apple Cider ◽  
Baited Traps ◽  
Full Complement ◽  
Protein Rich ◽  
Trap Catches ◽  
Olfactory Behaviour ◽  
Preference Experiment

Worldwide monitoring programs of the invasive fruit pest Drosophila suzukii Matsumura (Diptera: Drosophilidae), using fermentation baits like apple cider vinegar (ACV), revealed a counterintuitive period of low trap catches during summer, followed by an autumn peak. In this study, we demonstrate that ACV baited traps indeed provide a distorted image of the D. suzukii population dynamics as it is possible to capture higher numbers during this “low capture period” with synthetic lures. It was hypothesised that the preference of D. suzukii populations for fermentation cues like ACV is most pronounced during autumn, winter and spring, while the flies prefer fresh fruit cues during summer and that this seasonal preference is related to the changing physiology of the flies over the season. To test this hypothesis, the preference between fermentation cues (ACV) and host fruits (strawberries) and the effect of physiology (sex, seasonal morphology and feeding, mating and reproductive status) was investigated both in olfactometer laboratory experiments and a year-round field preference experiment. In olfactometer experiments we demonstrated that protein deprived females, virgin females with a full complement of unfertilised eggs and males show a strong preference for fermentation cues while fully fed reproductive summer morph females generally prefer fruit cues. These findings indicate that D. suzukii is attracted to fermentation volatiles in search of (protein-rich) food and to fruit volatiles in search of oviposition substrates. Winter morph and starved females displayed indiscriminating olfactory behaviour. In the field preference experiment, the hypothesised seasonal shift between fermentation and fruit cues was confirmed. This shift appeared to be highly temperature-related and was similarly observed for summer and winter morphs.

Ecology of juvenile and adolescent banana prawns, Penaeus merguiensis, in a mangrove estuary and adjacent off-shore area of the Gulf of Carpentaria. I. Immigration and settlement of postlarvae

1980 ◽  
Vol 31 (5) ◽  
pp. 635 ◽  
Author(s):  
DJ Stapels
Keyword(s):  
Water Temperature ◽  
River Mouth ◽  
Flood Tide ◽  
Trade Wind ◽  
Wet Season ◽  
Annual Cycles ◽  
North West ◽  
Immigration And Settlement ◽  
Physical And Chemical ◽  
The Relationship

The hydrology of the Norman River and adjacent off-shore region in the Gulf of Carpentaria is dominated by the alternation of a summer north-west monsoon and a winter south-east trade wind. The seasonality in both air temperature and rainfall is reflected in marked annual cycles of water temperature, salinity, and dissolved oxygen and nutrient (nitrate and silicate) levels. Near the mouth of the river; water temperature ranged from 15.0�C in June to 32.7�C in February, while salinity ranged from c. 0‰, in December and February to 38.2‰, in September. Postlarval banana prawns, P. merguiensis, were found in the river from November to May. but immigration was essentially restricted to the period immediately preceding the wet season (mid November). Maximum numbers ofjuvenile prawns occurred approximately 2 weeks later. A marked tidal periodicity in the movement of postlarvae was observed; postlarvae were present in the water column at the mouth of the river only during the flood tide with maximum numbers moving into the river at the time of maximum flood tide velocity. Incoming postlarvae settled out in the shallow water along the banks of the river (within 10 m of the shoreline), inland as far as 85 km. A lager catch of smaller prawns 48-72 km up-stream (salinity 10-20‰,) suggested that this area was the main settlement area for postlarvae. The population, however, contracted towards the river mouth during the wet season. concentrating the prawns in an area extending only a few kilometres up-river. Most prawns were caught on the muddy substrate adjacent to the mangrove (Avicennia sp.) fringe which lines the numerous bends in the river. Mechanisms for transporting larvae into the estuary and the relationship between the seasonality of physical and chemical parameters and immigration of postlarvae are discussed.

scholarly journals Aedes vector–host olfactory interactions in sylvatic and domestic dengue transmission environments

2019 ◽  
Vol 286 (1914) ◽  
pp. 20192136 ◽  
Author(s):  
David P. Tchouassi ◽  
Juliah W. Jacob ◽  
Edwin O. Ogola ◽  
Rosemary Sang ◽  
Baldwyn Torto
Keyword(s):  
Aedes Aegypti ◽  
Yellow Fever ◽  
Disease Vectors ◽  
Domestic Environment ◽  
Practical Applications ◽  
Baited Traps ◽  
Dengue Transmission ◽  
Trap Catches ◽  
Human Primate

Interactions between Aedes ( Stegomyia ) species and non-human primate (NHP) and human hosts govern the transmission of the pathogens, dengue, zika, yellow fever and chikungunya viruses. Little is known about Aedes mosquito olfactory interactions with these hosts in the domestic and sylvatic cycles where these viruses circulate. Here, we explore how the different host-derived skin odours influence Aedes mosquito responses in these two environments. In field assays, we show that the cyclic ketone cyclohexanone is a signature cue for Aedes mosquitoes to detect the NHP baboon, sykes and vervet, whereas for humans, it is the unsaturated aliphatic keto-analogue 6-methyl-5-hepten-2-one (sulcatone). We find that in the sylvatic environment, CO 2 -baited traps combined with either cyclohexanone or sulcatone increased trap catches of Aedes mosquitoes compared to traps either baited with CO 2 alone or CO 2 combined with NHP- or human-derived crude skin odours. In the domestic environment, each of these odourants and crude human skin odours increased Aedes aegypti catches in CO 2 -baited traps. These results expand our knowledge on the role of host odours in the ecologies of Aedes mosquitoes, and the likelihood of associated spread of pathogens between primates and humans. Both cyclohexanone and sulcatone have potential practical applications as lures for monitoring Aedes disease vectors.

Effet de certains paramètres physico-chimiques sur les relations prédateurs–proies dans les populations de copépodes cyclopoïdes des mares temporaires d'eau douce

1986 ◽  
Vol 64 (1) ◽  
pp. 8-11
Author(s):  
Louise Vallières ◽  
Antoine Aubin
Keyword(s):  
Organic Matter ◽  
Body Size ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Feeding Ecology ◽  
Mineral Content ◽  
Abiotic Factors ◽  
Size Class ◽  
Regression Analyses ◽  
Physical And Chemical

Copepod populations of three temporary freshwater pools (Alnus unit, Carex unit, and Molinia unit) were studied using a standard approach (species versus abiotic factors) and a holistic one (body size and feeding ecology). Multiple regression analyses of data indicate that the physical and chemical features of water (temperature, pH, dissolved oxygen, mineral content, and depth) explain 62 to 98% of the variability of carnivorous copepods, while the abundance of their prey accounts for much less. No size class of prey seems to be preferred. The abundance of decaying organic matter, typical of such pools, would result in an overabundance of prey. Predators would then be under the control of nonalimentary factors.

scholarly journals Distribution of benthic centric diatom Pleurosira laevis (Compère, 1982) in different substrate type and physical and chemical variables

2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Moslem Sharifinia ◽  
Zohreh Ramezanpour ◽  
Javid Imanpour Namin
Keyword(s):  
Relative Abundance ◽  
Pearson Correlation ◽  
Growth Conditions ◽  
Centric Diatom ◽  
Substrate Type ◽  
Field Surveys ◽  
Physical And Chemical Variables ◽  
Phosphate Silicate ◽  
Physical And Chemical ◽  
Substrate Types

Abstract: Aim This contribution reports the first regional occurrence of Pleurosira laevis in the Masuleh River, Iran and additionally describes the pattern of occurrence along the Masuleh River and among four substrate types. The aim of this study was to assess the effects of substrate type and physical and chemical variables on distribution of centric diatom P. laevis. Methods At each station, triplicate samples were collected from 4 substrata. Epilithic (assemblages on rock), epidendric (assemblages on wood), epipsammic (assemblages on sand), and epipelic (assemblages on mud) diatom and water quality sampling was done four times at 5 stations. Physical and chemical variables including total nitrate, total phosphate, silicate, Fe2+, EC, and pH were also determined. Samples preserved in 2% for formalin solution and transferred to the laboratory, boiled with acid (HNO3: H2SO4; 2:1), centrifuged, identified, and counted. Cluster analysis was performed to indicate the main differences and similarities in diatom abundance amongst substrates sampled and amongst sampling stations. Results The highest (12.54 ± 1.54) and lowest (0.74 ± 0.10) abundance was obtained from wooden and muddy substrates at stations S5 and S4, respectively. The highest abundance was observed in the wooden substrate among all of sampling stations where showed significant differences (P < 0.05) with the other substrates. The hierarchical clustering based on relative abundance of P. laevis distinguished two clusters amongst the four substrate types. Rougher and more stable substrates (wood, sand, and stone) clearly separated from smooth and unstable substrates (mud). Based on relative abundance of P. laevis on rougher substrates, epidendric and epipsammic species had the highest similarity. Results of Pearson correlation showed that relative abundance of P. laevis had a significant correlation with EC, TN, TP, and Fe2+ concentrations (P < 0.05) whilst no significant correlation was observed with pH, temperature, and SiO2 concentration (P > 0.05). Conclusion We conclude that wood substrata can be substituted for one another during field surveys. Results from this study demonstrate that the type and roughness of the substrate both influence the attachment of P. laevis and its subsequent growth conditions.

CHANGES IN RELATIVE ABUNDANCE OF THE FLEA BEETLES PHYLLOTRETA STRIOLATA AND PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE) IN SASKATCHEWAN PARKLAND WITH INCREASING DISTANCE FROM THE BOREAL FOREST

1984 ◽  
Vol 116 (4) ◽  
pp. 653-656 ◽  
Author(s):  
L. Burgess
Keyword(s):  
Boreal Forest ◽  
Relative Abundance ◽  
Allyl Isothiocyanate ◽  
Phyllotreta Cruciferae ◽  
Phyllotreta Striolata ◽  
Flea Beetles ◽  
Baited Traps ◽  
Sweep Net

AbstractMean catches of Phyllotreta striolata (F.) in allyl isothiocyanate baited traps decreased southwards from the boreal forest and northern parkland to the central parkland of Saskatchewan, while the opposite was true for Phyllotreta cruciferae (Goeze). Similar trends in the relative numbers of the two species were evident in sweep net catches in canola crops.

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