Seasonal changes in environmental conditions have a substantial impact on shellfish metabolism and physiology. Metabolic activities are the result of complex interactions between food availability, environmental conditions, growth, and reproduction, as well as interspecies and intraspecies relationships. In this study, scallops were collected and kept in captivity in order to study the impact of environmental variables without addressing intraspecific relationships. The queen scallop Aequipecten opercularis, a commercially sought-after shellfish harvested in nature with towed fishing gear such as dreadlocks and trawls, was the subject of this study. Scallops were gathered from the Medulin Bay area in the northern Adriatic and cultured for a year in pools with continuous seawater to analyze the seasonal impact of environmental variables on growth, physiological state, and biochemical parameters. In addition to daily maintenance and feeding, shellfish were monitored for parameters that correspond to seasonal fluctuations of seawater in a year-round cycle. The acquired results show changes in somatic (muscle, gonadosomic and condition) indices as well as in morphological (total body mass, wet tissue mass, shell's height, length, and thickness) and biochemical parameters (the tissues' water, protein, fat, sugar, and ash content) during four seasons in captivity. Temperature, pH, and the amount of dissolved oxygen affected the scallops' condition index, protein, and carbohydrate content, while all environmental parameters of seawater influence the quantity of water in their tissues: the positive influence of temperature, pH, and dissolved oxygen, as well as the negative influence of conductivity and the oxidoreduction potential.