Veganism & food ethics: input, anyone?
For many, veganism seems to be a journey... maybe I'm on that track; I’m not sure. For now, I identify as an 'ecovegavore'. I'm not vegan -- though I'm 99% herbivorous, and avoid leather, wool, products that test on animals, etc. I grew up in a veg-friendly family, so have been more plant-based than not for most of my life... I eat no mammals or birds, no factory farmed animal anything, and no dairy from any source; eggs only rarely (maybe once or twice a month, in the summertime) -- from pet-chicken eggs when my friend's family has more (leftover after slow farmers'-market-days) than they can use. I also eat local honey sometimes, from eco-friendly local beekeepers I know personally. About... mmm, once a month? something like that... I might eat local catfish/ tilapia/ mussels/ oysters, or (when I'm on the coast) clams or local (nonthreatened-species) saltwater fish that I catch myself.
Here's my current thinking, though I'm open to ideas & debate...
Premise 1: I don't think it's inherently wrong for a creature to eat another creature -- *if* it's necessary. A cougar's attack on a deer isn't immoral: cougars are obligate carnivores, doin' what they gotta do. My human body needs omega-3s and B-12; if I (not a corporation, but *me* myself, just another creature) go out and get those from the lowest on the food chain I can find them (i.e. mussels, oysters, etc.), how is that different? I do eat a good bit of nutritional yeast, but most sources agree one shouldn't count on one food exclusively, for B-12; I don't live near a good source of sea veggies... so, what's the fundamental moral difference between a shellfish becoming prey to me (who needs it), instead of an otter (who needs it)?
Premise 2: I try to eat 'real food'/ whole food, vs. processed food, as much as possible -- about 85% of my food purchases consist of 1-ingredient foods (nuts, seeds, fruits, veggies, legumes, flour, cornmeal, etc.) -- and I look for local sources, whenever possible. I think reliance on processed/ highly transported food is not desirable, for both health & environmental reasons. In the cultivation, processing, packaging, and transportation of items such as B-12 fortified products, B-12 & omega-3 supplements, and vegan sweeteners... it seems to me there would be MORE animal death and environmental degradation (insects, nematodes, & amphibians affected by pesticides; habitat loss from agriculture and processing plants; CO2 emissions from processing & transport, of both product & packaging) than ‘1-ingredient’, naturally occurring things like honey and oysters. Wouldn’t the artificial production of these nutrients do more damage, overall, to *more* living things?
Premise 3: I think 'food-for-profit', as an exclusive model of production, has been a harmful shift in human sociology, over the last few decades... I think at least a partial shift back to 'backyard agriculture'/ partial self-sustainability as the norm (rather than 100% for-profit/ conventional agriculture) would have huge benefits -- on human health and on other creatures' well-being (wild & domestic), as well as on reduced environmental degradation. I think backyard chicken-keeping for eggs, and individual bee-keeping for honey -- both very sustainable/ low-eco-impact food-production strategies -- have ethical/ environmental advantages over, say, buying prepackaged seitan from a corporation 17 states away, or vegan sugar from another continent. With eggs especially... I know some very happy and personable pet hens, who are as loved and content as any cherished pet dog or cat; unfertilized eggs thrown out, for vegan 'non-exploitation' principles? ... that just doesn't seem right, to me -- it seems wasteful. And beekeepers (like oyster farmers) tend to be fierce advocates for environmental non-trashing... bees need an environment without indiscriminate artificial pesticides (like oysters need crystal-clean water), so those who raise them tend to advocate for conditions that benefit the creature in question. Isn't there a fundamental difference between symbiosis and exploitation?
In embracing the goal of ‘less harm to other living things,’ there seem to me to be some gray areas in food ethics... maybe I’m just not an absolutist by nature; I tend to look for the ‘big picture,’ not necessarily just the close-up... However, I’m also not interested in rationalization -- for the past few years, my diet has been steadily evolving, as I continue to think things through. I’m not looking to justify or demonize any pre-selected conclusions; rather I’m in the process of considering my own particular world view, regarding the choices that do the least harm to the world around me.
I’m interested in arguments from all sides, as long as they are thoughtfully presented... I look forward to considering others’ viewpoints on this topic.

Hello Evz
I read your post a couple of times to try and get a sense of what you are saying/asking. I'm not going to try and cover everything you said but want to say something. I think it's fabulous that you are conscientious about your food choices and that you are making purchases prudently with a view to reducing your negative impact on the environment , me too!
On premise 1) you said: "so, what's the fundamental moral difference between a shellfish becoming prey to me (who needs it), instead of an otter (who needs it)?".......An otter needs it and can't/doesn't have the ability to ask the question you just asked. The shellfish may be eaten by you or the otter, so it may not ultimately make a difference to the life of the shellfish either way. That said, your choice has as I see it two impacts, one on yourself the other on those viewing you.
If I ate shellfish because I like to or for the nutritional benefit, I feel I'm doing so because I can, because I have the power to, after all who can stop me. In actuality I can get the nutritional benefits from other sources e.g. hemp which is a complete protein which has all 9 essential amino acids my body doesn't make and omega fatty acids in the right balance of 3s 6s & 9s. For me that means not taking the life of another earthling. Does that mean no other animal died or suffered in the production/shipping of hemp, most likely, and to be truthful it probably did. Which brings me to those viewing me, and perhaps touches on your point about the bigger picture.
One difference I can make to those around me (which is very/more important to me) is showing that we humans can live a healthy fulfilled life without taking the life of other sentient beings. Yes a shellfish can be viewed as just a shellfish, but where does someone observing me (the public in general) draw the line, if a shellfish is ok to eat what about a chicken, what about a pig, what about a dog, what about a horse. It becomes a slippery slope to acquiescing to all those other 'food' choices and can easily lead to other areas of life for example should I wear leather, fur , wool, silk etc.
My personal view as a vegan is that by example I can show that mankind can make compassionate choices that aren't based on cultural/social approval, but rather on egalitarian values that extend to all other creatures on this planet.
I'd be happy to respond again to any further comments you may have and thanks for taking the time to share your thoughts with all of us :)