Spawning strategy of Engraulis anchoita (Pisces, Engraulidae) in the continental shelf waters off Argentine

PÁJARO, M.; MARTOS, P.; LEONARDUZZI, E.; MACCHI, G.J.

Lisboa

Simposio; Symposium Reproductive and Recruitment Processes of Exploited Marine Fish Stocks; 2007

NAFO

Engraulis anchoita eggs were analyzed with the aim of describing the relation with the physical processes observed in the spawning area. Argentine anchovy is the most abundant fish resource in the Southwest Atlantic OceanSouth of 34°S at least two populations of E. anchoita exist separately at approximately 41°S. During spring the Northern stock is found in coastal sectors of the northern Argentine continental shelf (34-41°S), where massive spawning occurs. Southern stock spawns along the Patagonian coast (41-48°S) during late spring-early summer. From 1993 to 2004 a series of 16 surveys were carried out in order to assess the spawning biomass of argentine anchovy. Anchovy eggs were collected from 1681 vertical hauls using a Pairovet net. Temperature and salinity were recorded with a CTD sensor. Annual mean anchovy eggs density ranged from 660 to 2162 eggs m for the Northern stock and from 425 to 1023 eggs for the Patagonian stock. The spawning area varied between 88516 and 148822 km for the Northern stock and between 39063 and 78440 km for the Patagonian stock. In the Northern area, spawning was associated with several oceanographic regimes; the higher egg densities were mainly observed in relation to the 50 m isobath and to a near-shore area east of an estuarine system. On the other hand, spawning in the Southern area was coupled with the Patagonian tidal front system and the higher egg abundance were observed in both sides, homogenous and stratified waters, of the front.