Michel Roggo / School of Scaled herring or Scaled sardine (Harengula clupeola), entering from the sea into the freshwater of the Laguna Yal Ku, Quintana Roo, Yucatan Peninsula, Mexico . Photographed for The Freshwat...

Michel Roggo / School of Scaled herring or Scaled sardine (Harengula clupeola), entering from the sea into the freshwater of the Laguna Yal Ku, Quintana Roo, Yucatan Peninsula, Mexico. Photographed for The Freshwate...

Franco Banfi / Pacific flatiron herring (Harengula thrissina) bait ball, Sea of Cortez, Baja California peninsula, Mexico, East Pacific Ocean.

Franco Banfi / Pacific flatiron herring (Harengula thrissina) bait ball, Sea of Cortez, Baja California peninsula, Mexico, East Pacific Ocean.

Franco Banfi / California Sea Lion (Zalophus californianus) hunting fish, Sea of Cortez, Baja California peninsula, Mexico, East Pacific Ocean.

Tony Wu / Japanese angelshark (Squatina japonica) engaged in ambush predation, leaping out of the sand to catch a small silver-stripe round herring (Spratelloides gracilis). The shark's extended jaws are clearl...

Pascal Kobeh / School of Red-ear herrings / Red-ear sardines (Harengula humeralis) Yucatan peninsula, Mexico. Caribbean.