Batch fecundity, spawning frequency and size at maturity of the Argentine anchovy (Engraulis anchoita) in the southwest Atlantic Ocean

LEONARDUZZI, E.; PÁJARO, M.; MACCHI, G.J.; HANSEN, J.

Lisboa

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

NAFO

The Argentine anchovy (Engraulis anchoita) is the most abundant pelagic species in the Argentine sea, with a extensive geographical distribution ranging 34° and 48°S. E. anchoita is batch spawner with indeterminate annual fecundity. Batch fecundity (BF), spawning frequency (SF) and size at maturity (L50%) of this species inhabiting waters off the Buenos Aires Province, from 34°S to 40°S, were estimated by using samples collected during the spawning peak (October) between 1993 and 2006. BF was fitted to a power function of total length (TL) and age, and to a linear function of ovary-free female weight (TW*), ranging from 1,034 (96 mm TL) to 34,505 (181 mm TL) hydrated oocytes. Significant differences were observed between the coefficients of the relationship BF vs TL and BF vs TW* estimated from different years. Inter annual comparison of the relative fecundity estimates showed similar results, with values ranging from 128 to 1,111 hydrated oocytes per female gram (without ovaries). Spawning frequency for the different sampled years was similar, ranging from 0.09 to 0.15. At these frequencies, a female anchovy spawned once every 11 or 6 days. L50% values showed variability among years ranging from 84.4 mm to 106.8 mm TL. Fluctuations of BF and L50% could be associated to variations in the availability of food, temperature, eggs size or age-size composition of the stock. On the other hand, SF did not show statistical difference between years, but it may be consequence of the higher variation coefficients estimated for this variable.