Spatial and temporal distribution patterns of pelagic fish eggs and larvae are analyzed in relation to physical, chemical and biological properties of continental shelf waters off Argentina. Pelagic species are the predominant component of the ichthyoplankton assemblages of each of seven different ecosystems analyzed. Spawning strategies of most species appear to be distinctly related to topographic features, circulation patterns and production cycles. In contrast, the anchovy, Engraulis anchoita, located off Buenos Aires and Uruguay maintains high densities of eggs and larvae over a wide temporal and spatial range, thus enabling this population to proliferate rapidly in response to episodic favourable conditions. Over the last 25 years, there has been a decrease of the regional egg production of some pelagic stocks, not subjected to fisheries exploitation. |