scholarly journals Variability of hydrometeorological situation during fish kill events in the summer seasons of 2010–2018 in the Sea of Azov

Trudy VNIRO ◽  
2020 ◽  
Vol 180 ◽  
pp. 116-127
Author(s):  
A. T. Kochergin
Keyword(s):  
Water Temperature ◽  
Wind Velocity ◽  
Summer Season ◽  
Sea Surface ◽  
Background Characteristics ◽  
Fish Kill ◽  
Typical Pattern ◽  
Satellite Imaging ◽  
Air Temperatures ◽  
Wind Activity

Hydrometeorological situations during the fish kill events that took place in the Belosaray, Obitochny and Kazantip Bays in the summer seasons of 2010–2018 have been analyzed. Average monthly background water and air temperatures and wind velocity are considered, as well as their average daily values before, during and after a fish kill event. It is shown that background characteristics of water temperature and wind velocity influenced the development of a fish kill event more directly and definitely than air temperature, which influence was only indirect. In the majority of cases, hydrometeorological situation, leading to fish kill event, developed according to the typical pattern with increasing air and water temperature and decreasing wind activity. In the northern bays, the Belosaray and Obitochny Bays, fish kill events were recorded during the first half of summer season, and in the southern bay, the Kazantip Bay, they occurred in the second half of it. Since 2012, due to significant decrease in vertical thermohaline stability and increase in water homogeneity, no significant fish kill events were recorded under various temperature and wind conditions. Satellite imaging of sea surface temperature confirmed typical course of fish kill event development: the temperature increased in the pre-event period and then, after the event, stayed high in the southern bays and decreased in the northern ones.

Skinfolds and resting heat loss in cold air and water: temperature equivalence

1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna
Keyword(s):  
Heat Transfer ◽  
Water Temperature ◽  
Heat Loss ◽  
Air Temperature ◽  
Indirect Calorimetry ◽  
Cold Water ◽  
Heat Conductance ◽  
Air Temperatures ◽  
Body Core ◽  
Male Subjects

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).

scholarly journals Predicting harvest of non-native signal crayfish in lakes — a role for changing climate?

2016 ◽  
Vol 73 (5) ◽  
pp. 785-792 ◽  
Author(s):  
Patrik Bohman ◽  
Lennart Edsman ◽  
Alfred Sandström ◽  
Per Nyström ◽  
Marika Stenberg ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Water Temperature ◽  
Temperature Data ◽  
Adult Survival ◽  
Winter Mortality ◽  
Freshwater Crayfish ◽  
Catch Per Unit Effort ◽  
Signal Crayfish ◽  
Cool Water ◽  
Air Temperatures

The signal crayfish (Pacifastacus leniusculus) was introduced to Sweden in 1960, and it has a high commercial and recreational value, but it may also have negative effects on native ecosystems. To better predict how climate warming will affect population dynamics of this cool-water crayfish, we explored the role of temperature and density dependence as explanatory factors of the subsequent years’ catch rates of commercially sized signal crayfish in four Swedish lakes. We found air temperatures to be good proxies for water temperatures in all lakes, except during winter. We could only obtain water temperature data for Lake Vättern, and winter temperature data were therefore only included in the analysis of catch-per-unit-effort patterns in this lake. Our results indicate that increasing mean air temperatures will potentially affect the population dynamics of cool-water freshwater crayfish species such as the signal crayfish. Based on data from four lakes, it seems that the population dynamics of signal crayfish are lake-specific and could be affected by either recruitment during the juvenile stage, the survival and growth of adults, or both. Increased fluctuations in water temperature during winter may potentially influence adult survival. To better predict the effects of global warming on the dynamics of cool-water crayfish populations, we suggest that future studies should investigate recruitment in crayfish along temperature gradients and the influence of variations in water temperature on winter mortality.

scholarly journals Sea surface temperature variations in the south-eastern BalticSea in 1960–2015

Baltica ◽  
2018 ◽  
Vol 30 (2) ◽  
pp. 75-85 ◽  
Author(s):  
Viktorija Rukšėnienė ◽  
Inga Dailidienė ◽  
Loreta Kelpšaitė-Rimkienė ◽  
Tarmo Soomere
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Air Temperature ◽  
Weather Conditions ◽  
Sea Surface ◽  
South Eastern ◽  
Air Temperatures ◽  
Joint Application ◽  
Open Sea ◽  
And Cluster Analysis

This study focuses on time scales and spatial variations of interrelations between average weather conditions and sea surface temperature (SST), and long-term changes in the SST in south-eastern Baltic Sea. The analysis relies on SST samples measured in situ four times a year in up to 17 open sea monitoring stations in Lithuanian waters in 1960–2015. A joint application of non-metric multi-dimensional scaling and cluster analysis reveals four distinct SST regimes and associated sub-regions in the study area. The increase in SST has occurred during both winter and summer seasons in 1960–2015 whereas the switch from relatively warm summer to colder autumn temperatures has been shifted by 4–6 weeks over this time in all sub-regions. The annual average air temperature and SST have increased by 0.03°C yr–1 and 0.02°C yr–1, respectively, from 1960 till 2015. These data are compared with air temperatures measured in coastal meteorological stations and averaged over time intervals from 1 to 9 weeks. Statistically significant positive correlation exists between the SST and the average air temperature. This correlation is strongest for the averaging interval of 35 days.

scholarly journals Studies on gonadosomatic index, fecundity and hatchability of domesticated stock of asala Schizothorax richardsonii (Gray) from Nallu River of Lalitpur District

Our Nature ◽  
2015 ◽  
Vol 12 (1) ◽  
pp. 19-27
Author(s):  
Suresh Kumar Wagle
Keyword(s):  
Water Temperature ◽  
Egg Size ◽  
Gonadosomatic Index ◽  
Winter Season ◽  
Summer Season ◽  
Reproductive Capacity ◽  
Schizothorax Richardsonii ◽  
Breeding Seasons ◽  
Frequent Observation ◽  
Hatching Rates

The present work embodies studies on the reproductive capacity of captive stock of asala Schizothorax richardsonii collected from Nallu River of Lalitpur district. Gonadosomatic index (GSI) estimates ranged from 3.08±0.9% in May to 26.55±1.8% in November. Positive correlation (r=0.667) was found between egg size and GSI. The egg size (2.7 to 2.9 mm) in October and November was significantly (P<0.01) larger than the eggs measured in other months. Based on peak GSI level, S. richardsonii spawned by manual stripping in two breeding season i.e. winter (October-November) and summer (Mach-April) in Godawari (1500 masl). Mean incubation period of fertilized eggs was 259 h and 248 h during winter and summer season at 14.2 to17.5 oC and 14.5 to15.5 oC water temperature, respectively. Percent hatching rates of eggs ranged between 38 to 90% and were not significantly different (P>0.05) between breeding seasons. Overripe eggs obtained during winter season breeding (16.5%) were significantly higher (P<0.01) than the summer season breeding (3.6%).  This suggests that more frequent observation of the spawner is necessary during winter season for recognizing their appropriateness to ovulation. DOI: http://dx.doi.org/10.3126/on.v12i1.12253Our Nature (2014), 12(1): 19-27

Sign in / Sign up

Export Citation Format

Share Document