After landing a shark for eating purposes, do you bleed the fish after you land it. Sharks have a high ammonia content associated with it's urine. It's a good idea to soak the fillets in milk, vinegar water or lemon water for about 4 hours prior to cooking.

I soak mine in milk over night and grill them on a hot fire.

how do you bleed them?

Cut deep, but not all the way through, just above the tail fin and let it hang in the water tail down to bleed out.

from the top or bottom?

I usually just cut through till you pass the spinal column, depending on shark species you may need the tail for length or ID. once you get the fillets, soak the cutup portions in in either salt water or vinegar water. I try to cut up before soaking, on the idea of the more surface area the better it drains out the impunities. I try to leave as much red meat on the skin,it more for looks in that one gets a whiter fillet. We usually grill with either Italian dressing or a mixture of mangos, salt, pepper, and a bit of olive oil. Top with cilantro/onions a minute before removing from the heat.

I've never bled a shark but I have bled plenty of Blue Fish. I cut them behind the head.