Sockeye salmon are blue tinged with silver in color while living in the ocean. When they return to spawning grounds, their bodies become red and their heads turn green. Sockeye can be anywhere from in length and weigh from . Two distinguishing features are their long, serrated gill rakers that range from 30 to 40 in number, and their lack of a spot on their tail or back. Sockeye salmon range as far south as the Columbia River in the eastern Pacific (although individuals have been spotted as far south as the 10 Mile River on the Mendocino Coast of California) and
Pain in fish birds, frogs, salamander, reptiles, fish, and crustaceans. A recent article by Howard Browman and colleagues provides an overview of what different perspectives regarding fish pain and welfare mean to in the context of aquaculture, commercial fisheries, recreational fisheries, and research. It has been argued that fish can not feel pain because they do not have a sufficient density of appropriate nerve fibres. A typical human cutaneous nerve contains 83% GroupC nerve fibres, however, the same nerves in humans with congenital insensitivity to pain have only 24–28% C-type fibres. Based on this, James Rose, from the University of Wyoming, has argued