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,
Pickled herring fur coat'), which are usually prepared with vegetables and seasoned with mayonnaise dressing. Brined herring is common in Ashkenazi Jewish cuisine, perhaps best known for vorschmack salad known in English simply as "chopped herring" and as schmaltz herring in Yiddish. In Israel it is commonly known as "dag maluach" which means "salted fish". Pickled herring can also be found in the cuisine of Hokkaidō in Japan, where families traditionally preserved large quantities for winter. In Nova Scotia, Canada, pickled herring with onions is called "solomon gundy" and is quite popular. (Not to be confused with the Jamaican pickled fish pâté