Volume 58

Changes in the Spatial Reproductive Pattern of Argentine Hake (Merluccius hubbsi) off Patagonia


Authors
Macchi, G., M. Pájaro
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Date: November, 2005


Pages: 506


Event: Proceedings of the Fifty Eighth Annual Gulf and Caribbean Fisheries Institute


City: San Andres


Country: Colombia

Abstract

The composition of maturity stages and movement of spawning hake females of the Argentine nor-Patagonian area (43° - 46° S) were analysed during a reproductive season (November 2004 – February 2005). In addition , variations of the length structure and sex rate were studied. In general, spawning females were concentrated inshore at the beginning of the reproductive season (November), but later they expanded to deeper waters reaching the most scattered distribution in January. During February, spawning activity was mainly observed offshore (near the 100 m isobath), but the increase of the spent maturity stage in this region suggests the movement of females to deep waters after spawning. Reproductive schools were characterised by a high proportion of males, which stayed in the spawning area for a long time in comparison with females. The analysis of the length distributions evidenced that larger females (> 50 cm total length) have a longer reproductive season than young specimens. In general, an expansion of the spawning area of Patagonian hake to deeper waters was observed during 2004 - 2005. In contrast to that observed in others years, spawning was not associated to the bottom thermal front and the water temperature in the offshore breeding area was lower than 9°C, which was previously considered as a limit value for the reproduction of the Patagonian hake.

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