Rahway River migrations. Fish ladders are inundated structures with small underwater steps that allow fish to navigate around a dam and continue their migration. Other approaches include removing obstructions that are inoperative or no longer serve their purpose, or improving water quality and reducing debris that obstructs passage. The fish targeted for upstream passage at the Rahway River Water Supply Dam are alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), gizzard shad (Dorosoma cepedianum), white perch (Morone Americana) and the endangered American eel (Anguilla rostrate). Alewife and blueback herring are collectively referred to as river herring due to their similarity in appearance, range,
Fish as food "fiscas") which was pronounced as it is today. English also has the term seafood, which covers fish found in the seas and oceans as well as other marine life used as food. Over 32,000 species of fish have been described, making them the most diverse group of vertebrates. In addition, there are many species of shellfish. However, only a small number of species are commonly eaten by humans. Fish can be prepared in a variety of ways. It can be uncooked (raw) ("e.g.," sashimi). It can be cured by marinating ("e.g.," ceviche), pickling ("e.g.," pickled herring), or smoking ("e.g.," smoked