Water temperature, time of exposure and population density are key parameters in Enteromyxum leei fish‐to‐fish experimental transmission

2020 ◽  
Vol 43 (4) ◽  
pp. 491-502 ◽  
Author(s):  
Amparo Picard‐Sánchez ◽  
Itziar Estensoro ◽  
Raquel Pozo ◽  
Oswaldo R. Palenzuela ◽  
Maria Carla Piazzon ◽  
...  
Keyword(s):  
Population Density ◽  
Water Temperature ◽  
Experimental Transmission ◽  
Temperature Time ◽  
Enteromyxum Leei

scholarly journals Limnology of wastewater treatment lagoons at Pagla, Narayanganj

1970 ◽  
Vol 40 (1) ◽  
pp. 35-40
Author(s):  
Md Ataul Gani ◽  
Md Almujaddade Alfasane ◽  
Moniruzzaman Khondker
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Population Density ◽  
Water Temperature ◽  
Significant Positive Correlation ◽  
Secchi Depth ◽  
Gradual Improvement ◽  
Mean Values ◽  
Chl A ◽  
Suspended Matters

Limnology of two wastewater treatment lagoons, (Lagoon numbers 1 and 10 are treated as L-1 and L-2, respectively) at Pagla, Narayanganj considering 15 water quality variables had been carried out for 10 months. Air and water temperature did not vary significantly. Secchi depth (Zs) showed gradual improvement from the lagoon 1 to lagoon 10 due to low loading of suspended matters. Improvement of water quality from L-1 to L-2 has also been observed in respect to alkalinity, conductivity and TDS. Similar trends were also seen for SRS and SRP. In L-1 anoxia occurred three times whereas it was absent in L-2. In the present study, improved DO prompted NO3-N and TDS concentration. However in L-2, mean values of SRP dropped by about 13% than L-1. A significant positive correlation between the density of phytoplankton and SRP in L-2 at 5% level was obtained. A total of 105 species of phytoplankton belonging to 6 different algal classes were recorded from the lagoons. Highest number of species was obtained from Chlorophyceae followed by Euglenophyceae, Bacillariophyceae, Cyanophyceae, Cryptophyceae and Dinophyceae. The population density of phytoplankton and that of zooplankton in L-1 was low compared to L-2. Higher number of genera and species occurred in L-2 than L-1. Chl a and pheopigment concentrations were also higher in L-2. Results indicated that water quality has increased in the treatment pond number 10. Key words: Limnology; Wastewater treatment lagoons; Pagla; Bangladesh DOI: http://dx.doi.org/10.3329/bjb.v40i1.7995 Bangladesh J. Bot. 40(1): 35-40, 2011 (June)

scholarly journals Temporal variation of Nitella furcata subsp. mucronata var. mucronata f. oligospira (Charophyceae) in the Ninféias pond, São Paulo State, southeast Brazil

2006 ◽  
Vol 20 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Norma Catarina Bueno ◽  
Carlos Eduardo de Mattos Bicudo
Keyword(s):  
Population Density ◽  
Temporal Variation ◽  
Water Temperature ◽  
Algal Biomass ◽  
Sao Paulo ◽  
São Paulo ◽  
Dry Period ◽  
Rainy Period ◽  
Reproductive Structures ◽  
Southeast Brazil

Temporal and spatial variation of Nitella furcata (Roxburgh ex Bruzelius) C. Agardh emend. R.D. Wood subsp. mucronata (A. Braun) R.D. Wood var. mucronata f. oligospira (A. Braun) R.D. Wood were studied at the Ninféias pond (23°38'18.9"S, 46°37'16.3"W), a tropical, shallow, mesotrophic reservoir located in the Parque Estadual das Fontes do Ipiranga Biological Reserve, Municipality of São Paulo, southeast Brazil. Water samples were collected monthly from October/1996 to October/1997 for turbidity, electric conductivity, pH, alkalinity, dissolved oxygen, nutrients, biomass, and algal phenology analysis. Spatial distribution pattern of algal biomass showed that all four sampling stations were similar among themselves during the whole study period. Regarding the temporal variation, greatest algal total biomass values (98.35-266.06 g.m-2) were measured during the rainy period whereas the smallest ones (48.86-170.56 g.m-2) were detected during the dry period. Algal population density peaked at all four sampling stations from October/1996 to April/1997 (rainy period) when the greatest values of air and water temperature, precipitation, solar radiation, turbidity, total nitrogen, and ammonium were measured allowing favorable conditions for the algal growth. Period from May/1997 (late fall) to October/1997 (early spring) was favorable to the development of reproductive structures (nucules and globules) with consequent decrease of algal biomass and population density, clearly suggesting the greatest energy allocation towards the development of sexual reproductive structures. This fact was confirmed by the canonic correspondence analysis that indicated strong correlation between nucules length and width, number of nucules per plant, and oospores length and width with the low values of pH and high ones of dissolved inorganic matter detected during the dry period. Consequently, environmental factors such as increasing of water temperature and nutrients availability at the Ninféias pond acted decisively towards growth and accumulation of algal biomass.

Aspects of the population dynamics of the western rock lobster, Panulirus cygnus George. II. Seasonal changes in the catchability coefficient

1974 ◽  
Vol 25 (2) ◽  
pp. 249 ◽  
Author(s):  
GR Morgan
Keyword(s):  
Population Dynamics ◽  
Population Density ◽  
Water Temperature ◽  
Linear Combination ◽  
Seasonal Changes ◽  
Stock Assessment ◽  
Water Salinity ◽  
Rock Lobster ◽  
Highly Correlated ◽  
Panulirus Cygnus

The catchability coefficient, q, of a population of the western rock lobster P. cygnus was calculated monthly from November 1969 to January 1973 using measurements of catch, effort, population density, and area of reef. The catchability coefficient varied significantly during this time and was positively correlated with water temperature and water salinity, and negatively correlated with the percentage of rock lobsters in a premoult condition. A linear combination of these three factors was highly correlated with the catchability coefficient (P < 0.001) and appears to offer a method of adjusting the catchability coefficient and so leading to an improved stock assessment for this species.

scholarly journals Growth of Xenopus laevis under different laboratory rearing conditions.

1995 ◽  
Vol 29 (2) ◽  
pp. 152-162 ◽  
Author(s):  
G. Hilken ◽  
J. Dimigen ◽  
F. Iglauer
Keyword(s):  
Population Density ◽  
Xenopus Laevis ◽  
Water Temperature ◽  
Water Level ◽  
South African ◽  
Optimal Growth ◽  
Growth Data ◽  
Laboratory Rearing ◽  
Research And Education ◽  
The One

Since the European frogs ( Rana spp.) have fallen under the German endangered species regulation, Xenopus laevis (South African Clawed Frog) is being used increasingly in animal research and education. Optimal growth rates and homogeneity of groups have not necessarily been attained as little statistical analysis of growth data has been available. Following metamorphosis, an as yet not understood variability of growth is exhibited by X. laevis. In this study the effect of environmental factors on this variability was determined. Feeding, population density, background colouring, water temperature, the availability of hiding places, water level and water care were each examined separately. Development of body weight and body length were recorded. A definite correlation between the feeding programme, population density, cover and water care on the one hand and growth on the other were seen. Of lesser importance were water temperature, water level and background colouring. The observed variability of growth is assumed to also be of ethological origin.

scholarly journals Environmental Study of Zooplankton in the Middle Part of the Shatt Al-Arab River, Basrah, Iraq

2019 ◽  
Vol 32 ◽  
pp. 85-96
Author(s):  
Alaa A.A. Maytham ◽  
Naeem S. Hammadi ◽  
Jassim M. Abed
Keyword(s):  
Population Density ◽  
Water Temperature ◽  
Dominant Species ◽  
Middle Part ◽  
Environmental Study ◽  
Ph Values

An environmental study of zooplankton on the Shatt al-Arab River was carried out in two stations from July until November 2018. A total of 34 taxa of zooplankton were recorded in this study, belong to Cladocera, Copepoda and Rotifera. Some species have disappeared and others have emerged during the study period but varying numbers of dominant species found during the search such as Acarocalanus gibber, and recorded in the station 1 in July and station 2 for all months such as cyclopoid nauplii of Copepoda. Water temperature ranged between (19-35) °C station 1 and between (18- 32) °C at station 2, Salinity values fluctuated between (4.05 and 15.42 ‰), (6.47- 12.2 ‰) at stations 1, 2 respectively. pH values ranged was between (7.3 to 7.9) and (7.1 to 8.5) at stations 1 and 2 respectively. Copepoda density ranged between (0.12 to 88.23) ind. l-1 at station 1 and between (0.94 to 69.73) ind. l-1 at station 2. Density of Cladocera fluctuated between (0.06 and 1.45) ind. l-1. Maximum and minimum densities were at station 1. The population density of Rotifera ranged between (0.06 ind. l-1 to 20.44) ind. l-1 at second station.

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