scholarly journals The effects of cold shock on freshwater fish larvae and early-stage juveniles: implications for river management

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Laura E Michie ◽  
Jason D Thiem ◽  
Craig A Boys ◽  
Simon M Mitrovic
Keyword(s):  
Freshwater Fish ◽  
Cold Shock ◽  
Fish Larvae ◽  
Early Stage ◽  
Age Groups ◽  
Freshwater Ecosystems ◽  
Fish Populations ◽  
Swimming Ability ◽  
Temperature Changes ◽  
Rapid Temperature

Abstract Temperature is essential to the maintenance of optimal physiological functioning in aquatic organisms. Fish can manage natural fluctuations in temperature; however, in freshwater ecosystems acute and rapid temperature changes can originate from sources such as large dams and industrial effluents. These rapid temperature changes may induce several physiological and behavioural responses that can result in lethal and sub-lethal consequences. The present study assessed immediate sub-lethal and short-term (10 days) lethal responses of three species of Australian freshwater fish larvae and early-stage juveniles to a range of different ‘field-relevant’ cold shocks (−4, −6, −8 and −10°C). Murray cod (Maccullochella peelii), silver perch (Bidyanus bidyanus) and golden perch (Macquaria ambigua) were tested at two age groups to elucidate the interaction between ontogeny and sensitivity to cold shock. Cold shock caused mortality and reductions in swimming ability (time to exhaustion and lines crossed) in all species of fish at both age groups. Sensitivity was correlated to the magnitude of cold shock; a 10°C drop in temperature caused the highest mortalities. Ontogeny interacted with the severity of cold shock; the younger fish experienced higher mortalities and greater impairment to swimming ability. This study demonstrates the potential lethal and sub-lethal impacts of cold shock on freshwater fish at a critical life-history stage. Understanding the impacts of cold shock will aid management of freshwater ecosystems for the benefit of fish populations, with the current study identifying critical life stages to be considered in remediation and guiding thresholds necessary to reduce the impact of cold shock on native fish populations.

Green synthesis of nanomaterials for early lung cancer detection

2018 ◽  
pp. 1-1
Keyword(s):  
Lung Cancer ◽  
Green Synthesis ◽  
Cancer Detection ◽  
World Wide ◽  
Early Stage ◽  
Age Groups ◽  
Early Lung Cancer ◽  
Lung Cancer Detection ◽  
Synthesis Of Nanomaterials

Lung cancer is the foremost cause of cancer-related deaths world-wide [1]. It affects 100,000 Americans of the smoking population every year of all age groups, particularly those above 50 years of the smoking population [2]. In India, 51,000 lung cancer deaths were reported in 2012, which include 41,000 men and 10,000 women [3]. It is the leading cause of cancer deaths in men; however, in women, it ranked ninth among all cancerous deaths [4]. It is possible to detect the lung cancer at a very early stage, providing a much higher chance of survival for the patients.

scholarly journals Comparison of Invasive Apple Snail (Pomacea canaliculata) Behaviors in Different Water Temperature Gradients

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1149
Author(s):  
Mi-Jung Bae ◽  
Eui-Jin Kim ◽  
Young-Seuk Park
Keyword(s):  
Water Temperature ◽  
Farming Systems ◽  
Freshwater Snail ◽  
Freshwater Ecosystems ◽  
Pomacea Canaliculata ◽  
Activity Levels ◽  
Self Organizing Map ◽  
Apple Snail ◽  
Temperature Changes ◽  
Organic Farming Systems

Pomacea canaliculata (known as invasive apple snail) is a freshwater snail native to South America that was introduced into many countries (including Asia and North America) as a food source or for organic farming systems. However, it has invaded freshwater ecosystems and become a serious agricultural pest in paddy fields. Water temperature is an important factor determining behavior and successful establishment in new areas. We examined the behavioral responses of P. canaliculata with water temperature changes from 25 °C to 30 °C, 20 °C, and 15 °C by quantifying changes in nine behaviors. At the acclimated temperature (25 °C), the mobility of P. canaliculata was low during the day, but high at night. Clinging behavior increased as the water temperature decreased from 25 °C to 20 °C or 15 °C. Conversely, ventilation and food consumption increased when the water temperature increased from 25 °C to 30 °C. A self-organizing map (an unsupervised artificial neural network) was used to classify the behavioral patterns into seven clusters at different water temperatures. These results suggest that the activity levels or certain behaviors of P. canaliculata vary with the water temperature conditions. Understanding the thermal biology of P. canaliculata may be crucial for managing this invasive snail.

scholarly journals Effect of the SARS outbreak on visits to a community hospital emergency department

CJEM ◽  
2006 ◽  
Vol 8 (05) ◽  
pp. 323-328 ◽  
Author(s):  
Michael Heiber ◽  
W.Y. Wendy Lou
Keyword(s):  
Emergency Department ◽  
Community Hospital ◽  
Early Stage ◽  
Age Groups ◽  
Respiratory Illness ◽  
Hospital Emergency Department ◽  
Infants And Toddlers ◽  
Hospital Emergency ◽  
Ed Visits ◽  
Number Of Visits

ABSTRACTObjectives:To examine the effect of severe acute respiratory syndrome (SARS) on visits to a community hospital emergency department (ED) during the early stage of the Toronto outbreak in 2003 and for the same period in 2004. We focused on visits for respiratory illness (SARS-like symptoms) and different age groups.Methods:This study is a retrospective review of ED discharge diagnoses obtained from a computerized database, examining the 4-week period starting March 28 for the years 2001-2004. We obtained the discharge diagnosis, age and visit date for each ED patient during the relevant time intervals, then compared visit data from 2003 and 2004 with a baseline derived from the average number of visits during 2001 and 2002. We constructed groupings based on age and respiratory-illness symptoms.Results:During the SARS outbreak in 2003, ED visits declined by 21% (95% confidence interval [CI], 18%–24%) over the 4-week study period. The greatest reduction was for combined infant and toddler visits (69%; 95% CI, 58%–79%); these did not recover the following year. However, during the SARS outbreak there was a large increase in the number of visits for respiratory illnesses in adults (61%; 95% CI, 46%–75%) and in teenagers (132%; 95% CI, 82%–182%).Conclusions:During the SARS outbreak, total ED visits fell. The relative decline was most notable for infants and toddlers. By contrast, there was an increase in respiratory illness–related visits for adults and teenagers. In 2004, the year following the SARS outbreak, visit patterns shifted toward baseline levels, but ED visits by infants and toddlers remained depressed.

scholarly journals Effects of multigenerational exposure and phenotypic variation on a freshwater fish species exposed to elevated carbon dioxide (CO2)

2021 ◽  
Author(s):  
◽  
Jenna Laurel Fleet
Keyword(s):  
Carbon Dioxide ◽  
Freshwater Fish ◽  
Elevated Co2 ◽  
Phenotypic Variation ◽  
Mrna Abundance ◽  
Fish Populations ◽  
High Co2 ◽  
Filial Generation ◽  
Behavioural Phenotypes ◽  
Carbon Dioxide Co2

The amount of dissolved carbon dioxide (CO2) and the acidity of aquatic ecosystems is increasing as atmospheric CO2 concentrations increase due to human activities. Changes in pH and dissolved CO2 can have considerable aversive effects on fish physiology and behaviour, which can result in negative effects on fish populations. Multigenerational studies have found that the conditions experienced by parents can have significant effects on the performance of their offspring and understanding these effects can help to predict how fish populations will cope in future conditions. Additionally, repeatable behavioural phenotypes are good predictors of trends in behaviour, can be useful predictors of other physiological and life history traits, and can be subject to selection pressures. Unfortunately, the effects of elevated CO2 on freshwater fishes over multiple generations, and the effects of behavioural phenotypes, are poorly understood. In my thesis, freshwater Japanese Medaka (Oryzias latipes) were used to investigate the influence of phenotypic variation and differences in time of exposure (generational) on biological responses to elevated CO2. Lab-reared medaka were divided into ‘responsive’ and ‘non-responsive’ groups based on behavioural differences from the population mean during acute exposure to high CO2 in a common shuttling and novel tank behavioural assay. Responsive and non-responsive fish in parental generation (P) were subdivided and exposed to either control (~480 ppm) or high CO2 (~1250 ppm) conditions over a 6-week period. Following this time, eggs from this generation were collected and randomly selected into either high or control conditions, where they were hatched and reared until maturation (filial generation one (F1), 18 weeks). Eggs from F1 were collected and hatched and reared in the same conditions as their parents until adulthood (filial generation two (F2), 24 weeks). Body condition (size, weight and length), behaviour (total distance moved, time spent in the outer zone of the behavioural arena, and swimming direction), reproductive (number of eggs, size of eggs, and survival to hatch) performance, and the relative abundance of various mRNA transcripts in whole brain tissue of fish was measured across these three generations. Behavioural phenotypes influenced reproduction for P and F2 generation fish, and growth for F1 and F2 fish; suggesting that intraspecific variation in behavioural phenotypes may influence how medaka respond to elevated CO2. However, behavioural phenotypes did not have a significant effect on mRNA abundance on genes targeted in my study. Multigenerational exposure to elevated CO2 were shown to improve the performance of offspring in some measures and resulted in changes of mRNA abundance of several genes. Transgenerational exposure, where a parent or grandparent was exposed to elevated CO2 but the offspring were not exposed to elevated CO2, resulted in some deleterious effects suggesting that, generally, exposure to environmental conditions that differ from that of their parents may put fish especially at risk. In my thesis, current CO2 exposure appeared to be the best predictor of overall condition, where fish exposed to elevated CO2 were worse off than fish exposed to control CO2 conditions. The results of this research contribute to filling a current gap of knowledge in understanding how freshwater fish will respond to future conditions over an ecologically-relevant time scale. Importantly, this information will contribute to generating more informed decisions on freshwater ecosystem management and future research directions. Marine and freshwater environments offer food and water security and are of high importance to the economy and the health of our planet, making my research relevant to our broader society.

Genetic introgression on freshwater fish populations caused by restocking programmes

2005 ◽  
pp. 117-125
Author(s):  
María José Madeira ◽  
Benjamín J. Gómez-Moliner ◽  
Annie Machordom Barbe
Keyword(s):  
Freshwater Fish ◽  
Fish Populations ◽  
Genetic Introgression
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