1. The organs to be examined are spleen, anterior kidney, and encephalon.

2. In animals, the brain, or encephalon (Greek for "in the head"), is the control center of the central nervous system, responsible for thought.

3. Trisomy 13 is associated with multiple Abnormalcies, including terrible mental defects and defects of the encephalon that lead to ictuss, hearing loss, and optic Abnormalcies

4. Thus, whole alevin (body length < 4 cm), viscera including kidney (4 cm < body length < 6 cm) or, for larger size fish, kidney, spleen, heart and/or encephalon, and ovarian fluid from brood fish at the time of spawning shall be the tissues to be sampled.