scholarly journals Bio-Ecological Traits of Western Tubenose Goby Proterorhinus semilunaris (Heckel, 1837): A Key to Understand Its Invasion Success

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1247 ◽  
Author(s):  
Gülşah Saç
Keyword(s):  
Standard Length ◽  
Natural Habitat ◽  
Invasion Success ◽  
Biological Traits ◽  
Relative Importance ◽  
Ecological Traits ◽  
Tubenose Goby ◽  
Significant Difference ◽  
Index Of Relative Importance ◽  
Proterorhinus Semilunaris

This study aims to contribute to the limited knowledge on the bio-ecological traits of the native Western tubenose goby, Proterorhinus semilunaris, which is considered to invade many inland waters in Europe and North America. During monthly sampling surveys from March 2012 to June 2013, the species was collected from the four stations in the Istranca River (Turkey) by electrofishing. The standard length and body weight of 310 samples varied between 1.4–6.1 cm and 0.08–7.09 g, respectively. The sex ratio of female to male was found to be 1.7:1.0, with a significant difference. The values of the exponent b in the length–weight relationship were approximately 3 for females, males, and all individuals, indicating an isometric growth. The size at first sexual maturity was 2.44 cm standard length (SL) for females and 2.29 cm SL for males. Absolute fecundity ranged from 56 to 344 eggs with a mean of 164 eggs. The food composition of the species comprised of 8 major groups: Insecta (Diptera, Ephemeroptera, Plecoptera, Odonata, Trichoptera, Coleoptera), Arachnida, Annelida, Gastropoda, Crustacea, Pisces, plant, and detritus. According to the results of modified index of relative importance (MI) and index of relative importance (IRI), insect and Diptera were the most prevalent prey for this fish. The present study has provided baseline information on the basic biological traits of the fish in its natural habitat for further understanding of this species success of invasion.

scholarly journals Diet of the rasptail skate, Rostroraja velezi (Rajiformes: Rajidae), off Piura, Peru

2021 ◽  
Vol 47 (2) ◽  
Author(s):  
Pamela Molina-Salgado ◽  
Joanna Alfaro-Shigueto ◽  
Adriana González-Pestana
Keyword(s):  
Feeding Behavior ◽  
Trophic Position ◽  
Stomach Contents ◽  
Relative Importance ◽  
Peruvian Coast ◽  
Significant Difference ◽  
Specific Index ◽  
Northern Peru ◽  
Index Of Relative Importance

Batoids are among the least studied group of vertebrates and one of the most vulnerable to fishing. The rasptail skate, Rostroraja velezi, is a bycatch species in northern Peru for which there are no studies on its diet. This research aims to document the diet of R. velezi on the northern Peruvian coast and to determine if there are sex-based differences in the diet. A total of 74 R. velezi stomachs were collected, 59 of which had stomach contents. The cumulative prey curve showed reliability in the number of samples collected. According to the prey-specific index of relative importance, diet was dominated by Acanthephyra sp. (31%), other unidentified Caridea (15%), and unidentified teleosts (17%). A low significant difference in diet between sexes was found (R = 0.21, P < 0.01). The trophic position of R. velezi was 3.9 ± 0.7. This species displays bentopelagic feeding behavior and it is a secondary predator in northern Peru.

scholarly journals Influence of preemergently applied herbicides on the yield and quality of caraway achenes (Carum carvi L.)

2008 ◽  
Vol 56 (2) ◽  
pp. 255-266
Author(s):  
Antonín Vaculík
Keyword(s):  
Essential Oil ◽  
Standard Length ◽  
Oil Content ◽  
Competitive Ability ◽  
Weed Species ◽  
Yield And Quality ◽  
Significant Difference ◽  
Positive Effect ◽  
Different Doses

Caraway has very low competitive ability against most of weed species. Therefore, it is important to choose a suitable herbicide control, especially at biennial caraway. The experiments with the herbicides applied in caraway were found in pure growth, with variety Kepron (with standard length of ve­ge­ta­ti­ve period). The aim of the trials was to find out the differences at achenes yiled and essential oil content after the treatment by the various herbicides, applied preemergently. Also, the selective ac­ti­vi­ty of individual herbicides was tested, including the different doses. The herbicides used in the ex­pe­ri­ments had enough level of selektivity on the plants of caraway. They had a positive effect on the yiled comparing to non-treated control variant in all observed years. There was no statistically significant difference in essential oil kontent between the treated variants and non-treated control. On the basis of these results, the most suitable herbicide was chosen for the „minor“ registration for caraway.

scholarly journals The Sediment Selectivity of Perinereis aibuhitensis Larvae: Active or Passive?

2021 ◽  
Vol 8 ◽  
Author(s):  
Jinghui Fang ◽  
Wei He ◽  
Shan Meng ◽  
Zengjie Jiang ◽  
Jianguang Fang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Habitat ◽  
Organic Matter Content ◽  
Experimental Period ◽  
Matter Content ◽  
Active Selection ◽  
Sediment Types ◽  
Significant Difference ◽  
Perinereis Aibuhitensis ◽  
Sampling Times

The selectivity of Perinereis aibuhitensis larvae on different sediment types was studied using an experimental behavioral device in the lab. There were six types of sediment with different organic matter content: 2.19, 2.30, 2.86, 3.25, 3.51, and 5.52%. The results indicated significant differences in the six treatments’ organic matter content (p &lt; 0.05). When the P. aibuhitensis larvae initially attached to the sediment, the larvae’s density showed no significant difference among the six treatments. The density of larvae decreased gradually during the experimental period. It increased with the increasing organic matter content in sediment at every sampling time, but there was no significant difference (p &gt; 0.05). The larvae’s specific growth rate in the first month was significantly higher than those in the second and third months (p &lt; 0.05). The mortality showed no significance at different sediments in equal sampling times, but the mortality was lower in high organic matter content sediments. This study showed that the P. aibuhitensis larvae did not make an active selection; random selection happened when initially attached to the sediment with different organic matter contents. Higher organic matter content in the sediment was more conducive to larvae survival, and the organic matter content is the limitation factor on the mortality and the density. The different densities in the natural habitat of P. aibuhitensis might occur due to the passive selection by the environment.

scholarly journals Influence of individual biological traits on GPS fix-loss errors in wild bird tracking

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ruth García-Jiménez ◽  
Antoni Margalida ◽  
Juan M. Pérez-García
Keyword(s):  
Loss Rate ◽  
Satellite Telemetry ◽  
Foraging Strategy ◽  
Biological Traits ◽  
Ecological Traits ◽  
Location Data ◽  
Global Positioning ◽  
Satellite Transmitters ◽  
Technical Factors ◽  
Solar Powered

AbstractIn recent decades, global positioning system (GPS) location data and satellite telemetry systems for data transmission have become fundamental in the study of basic ecological traits in wildlife biology. Evaluating GPS location errors is essential in assessing detailed information about the behaviour of an animal species such as migration, habitat selection, species distribution or foraging strategy. While many studies of the influence of environmental and technical factors on the fix errors of solar-powered GPS transmitters have been published, few studies have focussed on the performance of GPS systems in relation to a species’ biological traits. Here, we evaluate the possible effects of the biological traits of a large raptor on the frequency of lost fixes—the fix-loss rate (FLR). We analysed 95,686 records obtained from 20 Bearded Vultures Gypaetus barbatus tracked with 17 solar-powered satellite transmitters in the Pyrenees (Spain, France and Andorra), between 2006 and 2019 to evaluate the influence of biological, technical, and environmental factors on the fix-loss rate of transmitters. We show that combined effects of technical factors and the biological traits of birds explained 23% of the deviance observed. As expected, the transmitter usage time significantly increased errors in the fix-loss rate, although the flight activity of birds revealed an unexpected trade-off: the greater the proportion of fixes recorded from perched birds, the lower the FLR. This finding seems related with the fact that territorial and breeding birds spend significantly more time flying than non-territorial individuals. The fix success rate is apparently due to the interactions between a complex of factors. Non-territorial adults and subadults, males, and breeding individuals showed a significantly lower FLR than juveniles-immatures females, territorial birds or non-breeding individuals. Animal telemetry tracking studies should include error analyses before reaching any ecological conclusions or hypotheses about spatial distribution.

The Effect of two different protein sources in the diet upon the incidence and prevalance of lameness in dairy cattle

1989 ◽  
Vol 1989 ◽  
pp. 66-66
Author(s):  
D N Logue ◽  
A Lawson ◽  
D J Roberts ◽  
E A Hunter
Keyword(s):  
Dairy Cattle ◽  
Crude Protein ◽  
Economic Consequences ◽  
Relative Importance ◽  
The West ◽  
Significant Difference ◽  
Series Of Experiments ◽  
Relationship Of ◽  
The Relationship ◽  
Locomotion Score

The importance of lameness in dairy cattle in UK in terms of its economic consequences and welfare considerations is well documented (Russel and others, 1982). While such epidemiological work has identified factors of importance in the aetiology of the various conditions associated with lameness it has been less successful in apportioning their relative importance, particularly for those conditions affecting the hoof. A series of experiments has been conducted at the West of Scotland College over the period 1983 to 1989 mainly investigating the relationship of nutrition and lameness. In one of these Manson and Leaver (1988) found a significant difference in the prevalence of lameness between two groups of cattle fed complete diets containing either 16.1 or 19.8% crude protein. They also found a significant increase in mean locomotion score (LS) and commented that further studies were needed to understand the dietary processes by which the hoof of the cow was predisposed to such problems.The objective of this experiment was to investigate the influence of the type of protein source in the concentrate upon the locomotion of the cows, the incidence and prevalence of lameness and finally on hoof hardness, shape, growth and wear.

scholarly journals Spatial and seasonal changes in the diet of Oligosarcus hepsetus (Characiformes, Characidae) in a Brazilian Reservoir

2005 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
F. G Araújo ◽  
C. C Andrade ◽  
R. N Santos ◽  
A. F. G. N Santos ◽  
L. N Santos
Keyword(s):  
Seasonal Changes ◽  
Prey Capture ◽  
Gut Contents ◽  
Relative Importance ◽  
Food Items ◽  
Dietary Shifts ◽  
Index Of Relative Importance ◽  
Almost All ◽  
Previous Autumn ◽  
Very High

We assessed spatial and seasonal changes in the diet of Oligosarcus hepsetus in order to describe the strategy developed by this species that allows their very high abundance in Lajes reservoir, Rio de Janeiro, Brazil. Fish samplings were carried out using gill nets, deployed during ca. 12 and 24 hours, between April 2001 and May 2002. A total of 289 individuals were examined, of which 97 showed gut contents. We used the index of relative importance (IRI) to compare probable dietary shifts, and the frequency of occurrence (% OC) to analyze possible ontogenetic influences on feeding. O. hepsetus showed carnivorous habits, feeding preferably on fish and insects, the latter of which occurred in 71.0% of the guts presenting contents. O. hepsetus consumed different items along the three reservoir zones: insects (61.0% IRI) and Cichla monoculus (38.9% IRI) in the lower zone; Lepidoptera (57.0% IRI) in the middle zone; and C. monoculus (77.0% IRI) in the upper zone. Food items changed seasonally with C. monoculus predominating in autumn 2001, and Hymenoptera and Lepidoptera in the winter. In spring almost all food was Lepidoptera (99.8% IRI), while in the summer Hemiptera dominated in the diet. In autumn 2002 Hemiptera (97.0% IRI) was dominant, in significant contrast with the previous autumn. Individuals smaller than 190 mm SL fed heavily on insects, while fishes predominated in the diet of individuals larger than 190 mm SL. Shifts in prey-capture ability among length classes suggest decreasing intraspecific competition. A higher food plasticity seems to be the strategy employed by this opportunist species, which used food resources available in the reservoir.

scholarly journals The Relative Importance of the Small Intestine and the Liver in Phase II Metabolic Transformations and Elimination of p-Nitrophenol Administered in Different Doses in the Rat

2020 ◽  
Vol 88 (4) ◽  
pp. 51
Author(s):  
Attila Almási ◽  
Pál Perjési ◽  
Emil Fischer
Keyword(s):  
High Pressure ◽  
Small Intestine ◽  
Phase Ii ◽  
Hepatic Function ◽  
Intestinal Lumen ◽  
Jejunal Loop ◽  
Relative Importance ◽  
Significant Difference ◽  
Metabolic Reactions ◽  
Different Doses

Intestinal and hepatic function have been investigated in phase II metabolic reactions and elimination of p-nitrophenol (PNP) in the rat. A jejunal loop was cannulated and recirculated with isotonic solutions containing PNP in different concentrations (0, 20, 100, 500, 1000 µM). Samples were obtained from the perfusate at given intervals. To investigate the metabolic and excretory functions of the liver, the bile duct was cannulated, and the bile was collected. Metabolites of PNP were determined by validated HPLC (high pressure liquid chromatography) methods. The results demonstrated the relative importance of the small intestine and the liver in phase II metabolic transformations and elimination of PNP. There were significant differences between the luminal and biliary appearances of p-nitrophenol-glucuronide (PNP-G) and p-nitrophenol–sulfate (PNP-S). The PNP-G appeared in the intestinal lumen at the lower PNP concentrations (20 µM and 100 µM) at higher rate than in the bile. No significant difference was found between the intestinal and the biliary excretion of PNP-G when PNP was administered at a concentration of 500 µM. However, a reverse ratio of these parameters was observed at the administration of 1000 µM PNP. The results indicated that both the small intestine and the liver might play an important role in phase II metabolic reactions and elimination of PNP. However, the relative importance of the small intestine and the liver can be dependent on the dose of drugs.

Relative Importance of Indicators of Teachers’ Professional Skills as Perceived by Senior High School Economics Teachers in Ghana

2017 ◽  
Vol 7 (3) ◽  
pp. 79-93
Author(s):  
Mumuni Baba Yidana
Keyword(s):  
High School ◽  
Teaching Experience ◽  
Senior High School ◽  
Survey Method ◽  
Instructional Planning ◽  
Relative Importance ◽  
Professional Skills ◽  
Instructional Assessment ◽  
Significant Difference ◽  
Descriptive Survey

AbstractThe study examined differences in perception among Senior High School Economics teachers on the relative importance of indicators of teachers’ professional skills, based on teaching experience. The study employed the descriptive survey method and comprised a sample of 115 professional Economics teachers drawn from the Central Region of Ghana. A self-designed questionnaire was administered on the respondents. The data were analysed using the t-test. The findings of the study showed that highly experienced Economics teachers perceive indicators of teachers’ skills of instructional planning as more important, relative to the experienced Economics teachers. Again, the finding showed a significant difference in perception between the highly experienced and experienced Economics teachers about the relative importance of the skills of instructional assessment. The study recommends the organisation of in-service workshops for sensitisation as well as the creation of a community of learners among SHS Economics teachers for the sharing of knowledge and experiences.

Relative phytotoxicity of parthenium weed (Parthenium hysterophorus L.) residues on the seedling growth of a range of Australian native and introduced species

2018 ◽  
Vol 69 (8) ◽  
pp. 837 ◽  
Author(s):  
Boyang Shi ◽  
Steve Adkins
Keyword(s):  
Seedling Growth ◽  
Invasion Success ◽  
Parthenium Hysterophorus ◽  
Grass Species ◽  
Pasture Grass ◽  
Lettuce Seedling ◽  
Non Invasive ◽  
Significant Difference ◽  
Phytotoxic Effect ◽  
Parthenium Weed

The invasive herbaceous species Parthenium hysterophorus L. (Asteraceae), commonly known as parthenium weed has rapidly become a significant weed in more than 30 countries. Parthenium weed litter taken from the introduced biotypes was relatively more phytotoxic than that taken from biotypes coming from the native range when tested on lettuce and this may indicate one reason for invasion success. However, no significant difference was observed in phytotoxicity to lettuce seedling growth when two Australian biotypes of parthenium weed were compared, one invasive and one non-invasive, indicating that invasiveness was not associated with litter phytotoxicity in all cases. Residue from the invasive parthenium weed biotype had a greater phytotoxic effect upon Australian native pasture grass species relative to the introduced pasture grass species with buffel grass (Cenchrus ciliaris L.) and bull Mitchell grass (Astreble sequarrosa C.E.Hubb) showing the greatest tolerance to parthenium weed phytochemicals. When compared with residue taken from plants that has a range of phytotoxic capacity, parthenium weed residue was considered to be only moderately phytotoxic suggesting that the phytotoxicity of its residue may not be the main reason for the plants invasive trait.

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