Thermal tolerance and standard metabolic rate of juvenile gilthead seabream (Sparus aurata) acclimated to four temperatures.

Abstract

Temperature variation affects the growth, maturation and distribution of fish species due to increasing constraints on physiological functions therefore, the aim of the present study is to evaluate effect of temperature on thermal tolerance and standard metabolic rate (SMR) of gilthead seabream (Sparus aurata). For this purpose, tolerable temperature ranges of juvenile gilthead seabream acclimated at 15, 20, 25, and 30°C for 30 days were estimated using dynamic and static thermal methodologies. The SMRs of the fish were also determined based on oxygen consumption rate (OCR). The dynamic and static thermal tolerance zones of gilthead seabream were calculated as 737 °C2 and 500 °C2, respectively, with a resistance zone area of 155.5 °C2. The SMR of the fish at the above acclimation temperatures (AT) was determined as 138, 257, 510, and 797mg O2 h-1 kg-1, respectively and were significantly different (P<0.01, n=10). The temperature quotient (Q10) in relation to the SMR of the fish was calculated as 3.45, 3.91, and 2.44 for acclimation temperature ranges of 15-20, 20-25, and 25-30°C, respectively. The fact that the SMR increased with rising temperatures and then decreased gradually after 25°C indicates that the temperature preference of juvenile gilthead seabream lies between 25 and 30°C. This study shows that gilthead seabream tolerates a relatively narrow temperature range, and consequently, a low capacity for acclimatisation to survive in aquatic systems characterised by temperature variations.