JUBILEE!
"Jubilee is the name used locally for a natural phenomenon that occurs sporadically on the shores of Mobile Bay, a large body of water on Alabama's Gulf Coast. During a jubilee many species of crab and shrimp, as well as flounder, eels, and other demersal fish will leave deeper waters and swarm—in large numbers and very high density—in a specific, shallower coastal area of the bay. A jubilee is a celebrated event along the Eastern Shores of Mobile Bay, and it attracts large crowds, many drawn by the promise of abundant and easy-to-catch seafood. Although similar events have been reported in other bodies of water, Mobile Bay is the only place where the regular appearance of this phenomenon has been documented. The oldest recorded jubilee dates back to the 1860s." Source: http://en.wikipedia.org/wiki/Mobile_Bay_jubilee