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

Abstract

Mauna, A. C., Franco, B. C., Baldoni, A., Acha, E. M., Lasta, M. L., and Iribarne, O. O. 2008. Cross-front variations in adult abundance and recruitment of Patagonian scallop (Zygochlamys patagonica) at the SW Atlantic Shelf Break Front. – ICES Journal of Marine Science, 65: 1184–1190. We studied cross-front variations in adult abundance and recruitment of Patagonian scallop (Zygochlamys patagonica) and their relationship with the Shelf Break Front and satellite-derived chlorophyll a in the Southwest 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 the analysis. One-way ANOVA was used to assess differences in recruitment and scallop abundance in a cross-front direction. The abundance of scallops was greatest (RC > 200 kg h−1) closer to the onshore side of the front or beneath it, and the East–West extension of scallop beds (∼40 km) matched the seasonal zonal displacement of the front (∼37 km). The highest CSAT gradients were west of or matched the position of the front. The annual mean position of the front correlated with the spatial variability in recruitment within areas where the species recruited successfully (RC > 2000 h−1). The spatial variability in adult abundance and recruitment of scallops is strongly related to the spatial variability in the position of the front and with the high CSAT concentrations associated with it.

Frontal circulation induced by up-front and coastal downwelling winds

“…In view of the importance of frontal processes to nutrient distribution and biological productivity in the East China Sea (Liu et al 1992) and other frontal systems (e.g., Govoni and Spach 1999;Mauna et al 2008), this work continues that of Chang et al (2010) to better understand the physics of windinduced frontal circulation. Cross-frontal circulation and mixing processes inferred from a set of high-resolution numerical experiments (0.25 km horizontal grid and 0 (1 m) vertical grid) are studied.…”

Satellite-derived SST data as a proxy for water temperature in nearshore benthic ecology

“…Temperature is a key factor controlling the distribution of species and physiological processes (Schils & Wilson 2006, O'Connor et al 2007, Byrne et al 2009, Staehr & Wernberg 2009, and easily accessible temperature data for the global ocean has facilitated considerable progress in our understanding of broad-scale biological patterns. As satellite-derived SSTs are now collected at high spatial and temporal resolutions and are readily available, their use as proxies for water temperature in nearshore benthic habitats has become increasingly popular (Donner et al 2005, Broitman et al 2008, Mauna et al 2008. While this application of SSTs has been useful in explaining ecological patterns, there have been very few detailed comparisons of satellite-derived data and in situ temperature data collected from shallow subtidal habitats.…”

Distribution and intensity of bottom trawl fisheries in the Patagonian Shelf Large Marine Ecosystem and its relationship with marine fronts

“…In six of the 7 years studied, the SBF concentrated more trawling activity than expected, suggesting this front as a relevant area for fishing demersal resources. Our results are in accordance with several studies showing the importance of the SBF on demeral (e.g., Podestá, ; Lucifora et al ., ; Alemany et al ., ) and benthic species (e.g., Bogazzi et al ., ; Mauna et al ., , ). The SBF is a large area that follows the continental slope for more than 1500 km (Piola, ) and is responsible for the high primary production of the region (Lutz et al ., ).…”

“…(e.g., Bogazzi et al, 2005;Mauna et al, 2008Mauna et al, , 2011. The SBF is a large area that follows the continental slope for more than 1500 km (Piola, 2008) and is responsible for the high primary production of the region (Lutz et al, 2010).…”

“…In that sense, there would be an energy flow between frontal areas and adjacent habitats due to organism's movement to forage and/or to defecate. The shelf-break front results from the meeting of two water masses (Malvinas Current and shelf water) and its position shows spatial variability, moving onshore and offshore seasonally (Carreto et al, 1995;Mauna et al, 2008). There is also evidence of water intrusions (nutrient-rich Malvinas Current waters) onto the continental shelf that potentially enhances nutrient enrichment over the region (Piola et al, 2010).…”