“In his new book, What A Fish Knows: The Inner Lives Of Our Underwater Cousins, Balcombe presents evidence that fish have a conscious awareness — or “sentience” — that allows them to experience pain, recognize individual humans and have memory. He argues that humans should consider the moral implications of how we catch and farm fish.
“We humans kill between 150 billion and over 2 trillion fishes a year. … And the way they die — certainly in commercial fishing — is really pretty grim, ” Balcombe says. “There’s a lot of change that would be needed to reflect an improvement in our relationship with fishes.”
In humans, sensory nerve fibres send electrical signals from the site of the stimulus to the spinal cord and then to the brain. Signals reached the thalamus, via the brain stem. The thalamus, a sort of relay station, which forwards signals for processing in different areas of the brain. One of these areas is the limbic system, which is the emotional centre of the brain. The neocortex, which is on the outer surface of the brain, handles conscious thought in the perception of pain.
All of these areas are present in fish, or the fish have the same function elsewhere in their brain.
- Fish have human-equivalent areas for pain processing
- Fish have areas for emotion, learning, memory, fear, social behaviour
- The pallium may be equivalent to the human neocortex for feeling pain
See also http://m.huffpost.com/us/entry/8881656
and: Aquatic animals, cognitive ethology, and ethics: questions about sentience and other troubling issues that lurk in turbid water: