In particular, in the El Nino years of 1997 to 1999, shifts in ocean currents pushed the warm water of the Kuroshio Current further into the Taiwan Strait, past Chiayi and Yunlin, blocking the southward movement of the cold waters from the mainland coast. The water temperature in the mullets 'former spawning grounds rose, and the southward-swimming mullet shoals stopped short of them.
特別一九九七至九九的聖嬰年，東太平洋洋流水溫升高，大海洋流互相牽動結果，南方黑潮暖水加強，衝過雲嘉外海，擋住大陸沿岸冷水團南下，西南外海產卵場水溫驟升，烏魚群因而停滯不前。