Patrones de distribución de las anomalías de temperatura superficial en el Mar Argentino. Su relación con la distribución de especies de interés comercial
The present research studies the spatial-temporal distribution patterns of the sea surface temperature anomalies (SSTA) and its relation with some of the most relevant commercial species in the Argentine Sea (SW Atlantic). The analysis is based on a monthly and weekly temporal series of the ATSM data and the sea surface temperature (SST) covering the period of December 1981 through November 2004, using the Reynolds/NCEP database as data source. The spatial scope of the study covers an area from the 33° S to 59° N, and includes the area within the coastal line and the 50 W, including the whole continental shelf, the shelf break zone, and the adjacent oceanic region. In order to assess the consistency of Reynolds/NCEP data for the purposes of this research a correlation and regression analysis was performed to compare these data with in situ data of TSM available from the SIAVO (INIDEP National Institute of Fisheries Research and Development databases). The correlation and regression values obtained supported the use of the Reynolds/NCEP. Correlation values ranged between 0.8 and 0.9 while the regression showed a R2 = 0,992. The SST and SSTA data were depicted spatially in a series of maps to identify singular events, and allow for the visualization of the range of variability of the SSTA distribution. In some particular cases it was also possible to identify homogeneous patterns of the SSTA distributions. The maps showed some years where the absolute values of the SSTA were unusually high, with occurrence of warm or cold event of variable spatial and temporal extension. In particular, positive anomalies of the SST were identified during 1998 -considered as the warmest of the last 400 years- that covered almost the whole area under study. March of 2004 also showed positive SSTA that influenced the hake Merluccius hubbsi and squid Illex argentinus fisheries. Ten grid points within the area under study were selected to study the behaviour of the temperature in the Argentinean shelf. A wavelets analysis was performed using the temporal series for these 10 grid-points, finding that dominant main frequencies were distributed in range from 1.6 to 2 years. The same analysis was conducted for the temporal series of three climatic indicators (SAM, TPI and SOI), which showed that there are similar frequencies between the IOA and those found in the grid points. Captures per unit effort (CPUE) and/or biomass for four commercial species (anchovy Engraulis anchoita; mackerel Scomber japonicus, hake M. hubbsi> and squid I. argentinus) were analyzed against the temporal series of ATSM and TSM. In some cases there was a strong correlation between TSM and biomass and/or CPUE for each species. In other cases no significant relation was observed.