Are we not supposed to eat shellfish because it’s described as an abomination in Leviticus?
There are a number of gastronomical abominations in the eleventh chapter of Leviticus, not just shell fish. However, all of these proscriptions were part of the Law of Moses. The Law of Moses was imposed on the Children of Israel until the expiation of the Lord, Jesus Christ.
When the resurrected Lord appeared to the Apostles, as recorded in the twenty fourth chapter of Luke, he told them that
all things must be fulfilled, which were written in the law of Moses, and in the prophets, and in the Psalms, concerning me.
Alma in the Book of Mormon (Alma 34:13) is more explicit in declaring the completeness of the fulfilment of the law of Moses through the great atoning sacrifice of the Savior. He recorded,
then shall the law of Moses be fulfilled; yea, it shall be fulfilled, every jot and title.
The law of Moses, or the law of carnal commandments, was as a schoolmaster to lead the children of Israel who had lived as slaves in bondage for four hundred years to an understanding of the Savior and his mission. When the Savior lived in mortality upon the earth, He taught the people his higher law, to live the spirit of righteousness, and demonstrated by the example of his life how it could be accomplished. As he said in 3 Nephi 27:27,
What manner of men ought ye to be? Verily I say unto you, even as I am.
.We must be quick to affirm that the law of the gospel of Jesus Christ includes all of the moral, spiritual aspects of the law of Moses, i.e. the Ten Commandments were never abolished.. But the outward signs that were used to govern the activities of the people were no longer needed, and were done away. So, it’s OK to eat shellfish.