Whatever you do, keep the flow of people steady. Just a few days without proper food could ruin your shark's pleasant, non-ramming attitude and make mopping up your day job.
Another problem facing the person who must feed humans to a shark is that unlike cows, most humans will not sit docilely (though there are a few) as you lower them on a massive gurney held by chains attached to a pneumatic engine into a shark-occupied body of water, no matter how many times you ask. In fact, most will threaten you.
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Try not to take these last threats personally, as it is all part of nature's system of self-defense. As adrenaline speeds through their bodies for the last time, their heightened reaction time causes many people to speak before thinking if what they're saying is going to hurt you. Also, by this time, you should have suitably distanced yourself emotionally from the intended meal in order that these remarks don't permanently scar you. A friend of mine once made the mistake of spending one last "quality day" with his wife and 6 year-old twins before feeding them to his Great White, POKEY. He spent most of the next afternoon a little upset.
Since you don't want the pet adversely affected, poisons and anesthetics are generally discouraged in subduing a meal. That leaves you three options to get a person into your shark:
1. overt violence
2. carefully concealed trap doors, and
3. very well-thought out arguments in favor of being eaten.