“White River Fish Kill” (2017) by Nina Chanel Abney.   PROSPECT.4 OPENS TO THE PUBLIC on Saturday. The international triennial features major exhibitions and inventive installations by more than 70 artists, including prominent artists of African descent, the late Barkley L. Hendricks, Derrick Adams, John Akomfrah, Hank Willis Thomas, Njideka Akunyili Crosby, Kahlil Joseph, Odili...