POSSIBLE MECHANISMS UNDERLYING FLUCTUATIONS IN THE FAR-EASTERN SARDINE POPULATION INFERRED FROM TIME-SERIES OF 2 BIOLOGICAL TRAITS

A cycle of fluctuation in the Far Eastern sardine, Sardinops sagax, po pulation is accompanied by an abrupt drop and recovery of fish size an d lipid content of parent fish, which may reflect a phase variation fr om coastal to oceanic and its reverse. The cycle begins with die survi val success of a smaller number of eggs produced by high-quality paren ts, which is triggered by a global climate change (density independent process), and finally ends in the survival failure resulting from an overexpansion of an enormous number of fish produced by low-quality pa rents (density-dependent process).