Assessment of Water Quality and Thermal Stress for an Artificial Fish Shelter in an Urban Small Pond during Early Summer

Abstract

This study evaluated water quality variations in an artificial deep pool (ADP), which is an underground artificial structure built in a shallow pond as a fish shelter. The water temperature, pH, dissolved oxygen (DO), and electrical conductivity (EC) were measured on an hourly basis in the open space and inside the ADP, and a phenomenological study was performed, dividing seasons into normal and rainy seasons and environments into stagnant and circulating conditions. The results showed that the water quality parameters inside the ADP exhibit lower fluctuations and diurnal variations compared with the open space. On average, the water temperature inside the ADP is lower than outside it by 1.7-3.7 • C in stagnant conditions, and by 0.6-0.7 • C in circulating conditions during early summer. Thermal stratification occurs inside the ADP but is temporarily disturbed due to the mixing from the forced circulation and the rainwater input through rainfall events. The ADP provided a constant and optimal water temperature for living and spawning for bitterling (i.e., 15.0-21.0 • C), which dominated in experimental pond during spring to summer. Most importantly, the ADP was able to significantly reduce the thermal stress of the fish in the study site, and as a result, the bitterling, a cool water fish species, could successfully become dominant. Finally, the deployment of the ADP appears to provide a practical alternative for effective fishery resources management to improve species diversity and fish communities in an artificial freshwater ecosystem (garden pond, park pond, other artificial wetlands, etc.).

Captivating Colors, Crucial Roles: Astaxanthin’s Antioxidant Impact on Fish Oxidative Stress and Reproductive Performance

“…Rapid temperature changes can stress fish and impact their metabolism. [67] Pollutants (heavy metals)…”

The physiological ups and downs of thermal variability in temperate freshwater ecosystems

“…Quantitatively assessing the cumulative potential of thermal stress requires the knowledge of the magnitude of thermal stress induced by preceding exposures. This may be derived from theoretical heat stress prediction models that predict the degree of stress using mathematical indices (Ahn et al ., 2019; Bevelhimer & Bennett, 2000), but these have never been empirically related to a real physiological response. To date, most indicators of heat stress during thermal variation are measured at the tissue/cellular level ( e.g ., lactate and HSPs) as factors that vary with time (Callaghan et al ., 2016; Corey et al ., 2017; Eldridge et al ., 2015; Gallant et al ., 2017; Tunnah et al ., 2016).…”