Evolutionary speaking, all the animals that care for their young or form bonds with other animals (same species) for cooperation have a higher likelihood of fee

Evolutionary speaking, all the animals that care for their young or form bonds with other animals (same species) for cooperation have a higher likelihood of feeling emotions that you mentioned in your comments. Pain might be universal but things like "love", "play", "excitement", "boredom" etc. are highly unlikely in crustaceans or even fish. So it's very clear that eating mammals and birds is ethically not okay but apart from the environmental reasons, eating sea food is probably not as bad as eating mammals/birds.