Cross-frontal variations in recruitment and adult abundance of the Patagonian scallop (Zygochlamys patagonica) in the SW Atlantic Shelf Break Front

MAUNA C.; FRANCO B.; BALDONI A.; ACHA E.M.; LASTA M.; IRIBARNE O.

ICES JOURNAL OF MARINE SCIENCE

Año: 2008 vol. 67 p. 1184 - 1190

1054-3139

We studied cross-frontal variations in recruitment and adult abundance of the Patagonian scallop (Zygochlamys patagonica) and its relationship with the Shelf Break Front variability and the satellite derived chlorophyll a in the South Western Atlantic between 38°S and 39°30´S. Integrated data from commercial fleets (CF, 1996-2005), research cruises (RC, 1998-2005), sea surface temperature (SST; 1985-1997) and satellite derived chlorophyll a (CSAT; 1998-2004) were included in our analysis. One-way ANOVA was used to assess differences in recruitment and scallop abundance in the cross-frontal direction. The results show that the highest scallop abundances (RC >200 kg h-1) were located mainly closer to the onshore side of the front or beneath it and the scallop beds E-W extensions (~ 40 km) matched the seasonal zonal displacement of the front (~ 37 km). The highest CSAT gradients are located at west or match with the front position. The annual frontal mean position is correlated with the spatial variability in recruitment within areas where this species was successful (RC >2000 ind h-1). The spatial variability in scallop recruits and adults abundance is strongly related to spatial variability in the position of front and to of the highest CSAT concentrations associated with that front. Keywords: abundance, marine fronts, recruitment, scallops, spatial pattern, Zygochlamys patagonica, Southwest Atlantic.