Browsing by Author "Mrubata, Ayabulela"

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    Salinity and temperature tolerance of the caridean shrimp, Palaemon peringueyi (Caridea: Palaemonidae)
    (University of Fort Hare, 2023-11) Mrubata, Ayabulela; Vine, N.G.
    Temperature and salinity are two of the most important environmental factors that influence the physiology of aquatic organisms, especially in the estuarine and coastal ecosystems. The interaction of salinity and temperature can be complex, with one variable acting as a modulating factor on the effects of the other and both factors have a huge impact on organisms as they can influence, modify and control an organism’s physiological rates. Studies on the effects of salinity and temperature on the survival of the caridean shrimp, Palaemon peringueyi were conducted for this study. Density experiments of P. peringueyi were first conducted in order to determine shrimp densities to be used in tests. An influence of appropriate densities (5, 10 and 15 individuals per litre) to the survival of adult shrimps (i.e. carapace length ≥ 9 mm) after 96-hour exposure was investigated. Highest survival (80%) was recorded for the density of five individuals per litre, with survival varying between 60 and 80%. The lowest survival was recorded for the highest density (i.e. 15 individuals). Therefore, individual instead of group exposures were used for salinity tolerance tests. P. peringueyi were able to tolerate test salinities (range: 5 to 55 in increments of 5) and highest survival (≥80%) was recorded at salinities of 15–45. Difference in survival between salinities was significant (p = 0.000541) and these were driven mainly by differences between 55 vs all salinities. Temperature tolerance was highest at 15°C, 20°C and 25°C where survival ranged between 73% and 100%. Temperatures of 5°C and 35°C resulted in mortalities. Temperature was thus found to have a more pronounced effect on survival (p = 0.000) while salinity had a less significant effect. The interactive effects of temperature and salinity were found to have a significant influence on the of P. peringueyi (p = 0.002).