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Revista de Biología Marina y Oceanografía 44(2): 497-510, agosto de 2009 Distribución de merluza (Merluccius hubbsi Marini, 1933) en el Mar Argentino (41°-48°S) en relación con parámetros oceanográficos durante el invierno (1996-2003)Distribution of the Argentine hake (Merluccius hubbsi Marini, 1933) in the Argentine Sea (41º-48ºS) in relation to oceanographic parameters during winter (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) Abstract.-Salinity and temperature data recorded during 1996-2003 within the distribution area of the Patagonian stock of Argentine hake Merluccius hubbsi were analysed. These oceanographic variables were then related to fluctuations in the abundance of the species by means of a generalized linear model. Mean bottom temperature and salinity fields were graphed and anomalies for this period were estimated. During 1998 and 2002 the highest and lowest mean temperatures were recorded, respectively, showing the most remarkable anomalies. Highest mean salinity was recorded during 1999 and in terms of anomalies during 2003 lowest salinities were recorded for the whole area. Highest juvenile concentrations were found in waters with bottom temperatures between 7ºC and 10ºC and salinities between 33.3 and 33.8 distributed to the north and within the San Jorge Gulf and in midshelf between the 50 m and 100 m isobaths, to the southern zone of the Valdés Peninsula. Adult concentration was higher at the centre of the shelf, decreasing towards the coastal sector, at approximately 6ºC and 9ºC and between 33.4 and 33.9. Regression coefficients evidenced highest juvenile abundances in shallow areas with low salinity, and highest adult abundances in regions with low temperature and high salinity. No spatial shifts in the distribution of the species were observed during marked temperature or salinity anomalies.Key words: Geographical distribution, temperature fields, salinity gradients, Southwest AtlanticResumen.-Se analizaron las variables de temperatura y salinidad en el invierno durante el período 1996-2003 en el área de distribución del efectivo patagónico de la merluza argentina Merluccius hubbsi; estas variables oceanográficas se relacionaron con las variaciones en la abundancia de la especie, a través de un modelo lineal general. Se determinaron los campos medios de fondo y las anomalías de temperatura y salinidad para ese período. El año 1998 presentó la temperatura promedio más alta y el 2002 la más baja, indicando las anomalías más destacadas. La salinidad promedio más alta se registró en 1999 y en términos de anomalías, el 2003 fue, en toda el área, de menor salinidad. Las mayores concentraciones de juveniles se observaron en aguas con temperaturas de fondo entre 7°C y 10°C y salinidades entre 33,3 y 33,8 distribuidas en el interior y norte del Golfo San Jorge y en la plataforma media, entre la isóbata de 50 y 100 m, hasta la zona sur de la Península Valdés. La distribución de adultos se concentró en el centro de la plataforma, disminuyendo hacia el sector costero, aproximadamente entre 6º y...

The Argentine hake Merluccius hubbsi represents the dominant demersal fish and one of the main fisheries in the Argentine Sea. We analyzed over 17 years (September 1997–February 2015) of satellite surface chlorophyll concentration (CHL) and sea surface temperature anomaly (SSTA) data in the main spawning (SUB) and nursery (SJG) areas of the Patagonian stock of M. hubbsi. The variability observed in these environmental conditions was related to interannual differences in the reproductive success of hake. CHL values were maximum during austral spring (October–November) and minimum during winter (June–August). Blooms started in late September and lasted on average 128 and 110 days at SUB and SJG, respectively. At SUB, average CHL at the time of reproduction, the day of occurrence of the maximum chlorophyll concentration, and fall SST anomalies were significantly related to recruitment (RVPA) a year later and to two Larval Survival Indices (LSISSB and LSITEP) considered. At SJG, RVPA, LSISSB, and LSITEP showed negative correlations with fall (March–May) SSTA. Total egg production was not related to fall SSTA or spring phytoplankton dynamics at SUB or SJG. Significant positive trends were observed in the time series of CHL and SSTA in the study area. The trends observed in CHL represent average increases of 40.7% and 35.7% since 1997 at SUB and SJG, respectively. The potential implications of long‐term changes in environmental conditions for hake reproductive success are discussed.

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