Unseasonal warm temperatures caused by El Niño have a profound effect on the fish populations of coral reefs in the South Pacific, scientists have found. An international team of biologists studied the arrival of young fish to the atoll of Rangiroa in French Polynesia for four years and compared their results with satellite and oceanographic data. They found that the El Niño event caused a sudden collapse in the plankton community and this led to a near absence of the young fish that are required to replenish adult stocks.