ABSTRACT
Fishermen have long been aware of the influence of environmental changes on the abundance and distribution of fishes. Short-term environmental fluctuations affect the distribution of fishes. For example, the seasonal change from spring to summer marks the return of many commercially important species from winter offshore areas to estuaries such as the Chesapeake Bay. Early Long Island and Virginia fishermen predicted the spring arrival of shad (Alosa) and weakfish (Cynoscion) with environmental indicators such as the flowering of the shad bush and the dogwood (Austin and Ingham, 1978). Long-term climatic changes are known to cause fish stocks to appear and disappear. In 1942, Ottestad reported a high correlation between 85 years of cod catches in the Vest Fjord, in northern Norway, and widths of pine tree rings, which were used as indicators of fluctuations in the climate of the area. Recent laboratory and field investigations by fisheries scientists have resulted in an increasing awareness of the impact of the environment on the stock size of commercially valuable species. If the environmental factors causing fluctuations in stock size were identified, this knowledge could lead to accurate predictions of where and when to fish to maximize a fisherman's catch.
