“Depressed,” with regard to a marine fishery, means the condition of a fishery for which the best available scientific information, and other relevant information that the commission or department possesses or receives, indicates a declining population trend has occurred over a period of time appropriate to that fishery. With regard to fisheries for which management is based on maximum sustainable yield, or in which a natural mortality rate is available, “depressed” means the condition of a fishery that exhibits declining fish population abundance levels below those consistent with maximum sustainable yield.