Marine stickleback populations live and breed strictly in the ocean. Sea-run stickleback fish are. anadromous, meaning that they are born in fresh water, spend most of their lives in the ocean, and. return to fresh water to breed. Freshwater stickleback fish live entirely in fresh water.
Among patients with Crohn's disease, 4% will have an anal fissure as the first manifestation of their Crohn's disease, and half of all patients with Crohn's disease eventually will develop an anal ulceration that may look like a fissure.
LINK / CITE ADD TO WORD LIST. noun. The definition of a fissure is an opening in the Earth, or a disagreement or split on an issue. 1  A long and narrow crack in the earth that forms an opening is an example of a fissure.2  When two members of a group have a disagreement and split on an issue, this is an example of a fissure.he definition of a fissure is an opening in the Earth, or a disagreement or split on an issue.