Please check your Bible. Leviticus DOES indeed list eating shellfish as an abomination along with a lot of other things I'm sure folks today wouldn't go along with -- slavery, illegal to wear blended fabrics, women's periods and killing disobedient children. So please, if you're going to quote your Bible, at least know what's in it.
"But all in the seas or in the rivers that do not have fins and scales, all that move in the water or any living thing which is in the water, they are an abomination to you." (Leviticus 11:10)
"They (shellfish) shall be an abomination to you; you shall not eat their flesh, but you shall regard their carcasses as an abomination." (Leviticus 11:11)
"Whatever in the water does not have fins or scales; that shall be an abomination to you." (Leviticus 11:12)
"For everyone who curses his father or his mother shall surely be put to death. He has cursed his father or his mother. His blood shall be upon him." (Leviticus 20:9)
"If a man lies with a woman during her sickness and uncovers her nakedness, he has discovered her flow, and she has uncovered the flow of her blood. Both of them shall be cut off from her people." (Leviticus 20:18)
"Your male and female slaves are to come from the nations around you; from them you may buy slaves. You may also buy some of the temporary residents living among you and members of their clans born in your country, and they will become your property." (Leviticus 25:44-45)
"...do not plant your field with two kinds of seed. Do not wear material woven of two kinds of material." (Leviticus 19:19)