Comparing cognition across vertebrate groups illuminates the basis of moral consideration — marine mammals and fish both show sophisticated behaviour, but differ substantially in neural architecture and the likely richness of their experiences.
Welfare science increasingly recognises that neural architecture alone does not determine the moral weight of an animals experiences. Fish, despite lacking a mammalian cortex, show consistent evidence of nociception and stress responses. Marine mammals, with their rich cognitive and social lives, are at the higher end of the welfare consideration spectrum. The practical implication is that both groups deserve welfare consideration, scaled to the evidence for experiential richness.