Preferred Temperature, Critical Thermal Maximum, and Metabolic Response of the Black Sea UrchinArbacia stellata(Blainville, 1825; Gmelin, 1791)

Abstract

ABSTRACT Populations of the black sea urchin Arbacia stellata present in the Gulf of California and outer Pacific Coast area are probably the result of colonization from the Panamic region. In the Pacific Coast of Baja California, this species experiences seasonal fluctuations of temperature. It was determined the preferred temperature (PT), critical threshold limits represented for Critical Thermal Maximum (CTMax) and oxygen consumption rate in organisms acclimated to 16°C, 19°C, 22°C, and 25°C in controlled conditions. The PT of A. stellata was determined in organisms using the acute method. As the acclimation temperature increases, the PT also increases significantly (P < 0.05) and decreases to 22.8°C. In the acclimation temperature of 25°C, PT for black sea urchins was 23.3°C ± 0.3°C. A direct relation was determined between the CTMax and acclimation temperatures being of 36.48°C ± 0.6°C, 37.64°C ± 0.76°C, 38.08°C ± 0.94°C, 38.42°C ± 0.71°C. The end point of CTMax was stage E4, where the sea urchins s...