From what I understand, Bivalvia (oysters, clams, etc.) can be considered plants as far as ethics goes. Insects probably don't feel much pain, but even if they do, factory farming them would be ethically raising them. Does that also apply to krill or shrimp? Are there any other animals that we don't have to worry about eating?

It doesn't really make much of a practical difference for me, as every animal that I might be ethically okay with eating is also something that I really don't want to eat. I could take krill oil pills, though.

Hi Daniel

DanielLC wrote:Insects probably don't feel much pain, but even if they do, factory farming them would be ethically raising them.

I don't agree. Slaughter on insect farms may not be humane and in some cases involves boiling alive (e.g., the Kreca company). There can also be problems prior to death. Insect attrition rates on farms are always nonzero; I would guess they're higher than for any other factory-farmed animal.

DanielLC wrote:From what I understand, Bivalvia (oysters, clams, etc.) can be considered plants as far as ethics goes ... Does that also apply to krill or shrimp? Are there any other animals that we don't have to worry about eating?

One important consideration is that many of these creatures are harvested in a way that can have effects on other species or the environment.

For example, one technique, (trawling) is using a net that can, as a bycatch kill 10-20x as many other creatures.

Another technique, (or as a result of trawling) is scraping the floor (damaging coral reefs and/or hurting larger creatures).

These reasons can be enough to avoid eating many (most? I'm sorry I don't have specifics here) of the creatures you mention.

Another good reason to avoid eating Bivalvia (oysters, clams, etc.), on top of erring on the side of caution, is the risk of mercury contamination. The following videos by Dr. Michael Greger shed some light on the risk of mercury poisoning that intake of fish and shellfish seems to pose, and the case for taking vegan capsules if anything:
http://www.youtube.com/watch?v=3l9T9t4s3uk
http://www.youtube.com/watch?v=X_RKtP4D9uI

His page is an excellent resource in general, always referencing studies directly, and often evaluating their methodology, strength and implications.