Influence of environmental conditions on the reproductive success and recruitment of the Argentine hake Merluccius hubbsi (southwestern Atlantic Ocean)

Abstract

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.

Evaluating the role of endogenous and exogenous features on larval hake nutritional condition

“…In agreement with our results, Marrari et al. (2019) suggested that the years with higher egg production lead to high densities of early developmental stages and consequently to higher density‐dependent mechanisms reducing the survival of juveniles and later recruitment to the adult stage.…”

“…Such densities of prey present in the stratified zone would allow greater efficiency in larval feeding since the energy costs associated with food search would be reduced. Supporting our results, Marrari, Macchi, Santos, and Leonarduzzi (2019) observed that the most favorable conditions for M. hubbsi recruitment and its larval survival were cold temperatures (colder than average fall temperatures) in combination with high spring chlorophyll concentrations. They suggested that the higher survival associated with colder seasons might be the result of less competition for food between hake larvae and other plankton predators.…”

Evidence of ocean warming in Uruguay’s fisheries landings: the mean temperature of the catch approach

“…Linear model relating the mean temperature of the catch (MTC) with the sea surface temperature anomaly (SSTA) and the fishing fleet diversity (Simpson index). **p < 0.01 more, recent reports from a nearby region concluded that the reproductive success indexes of Argentine hake were negatively correlated with SST, particularly in autumn (late larval or early juvenile phase; Marrari et al 2019). In contrast, the wide thermal niche of whitemouth croaker and its affinity for warm waters mean that this species may be less sensitive to an increase in regional SST.…”

Sensitivity of Shelf Sea Marine Ecosystems to Temporal Resolution of Meteorological Forcing

“…Phytoplankton phenology is known to be strongly impacted by meteorological variables, particularly wind and solar irradiance. The timing of spring and autumn phytoplankton blooms have consequences that cascade through the food web (Edwards & Richardson, 2004) and have been shown to affect fish stocks and spawning, copepod reproduction and shrimp survival (Kodama et al, 2018;Leaf & Friedland, 2014;Marrari et al, 2019;Platt et al, 2003;Richards et al, 2016). If high-resolution meteorological data is not available, the ability of hydrodynamic-ecosystem models to capture the impact of short-term fluctuations in wind stress, light availability and other key meteorological variables on bloom phenology and carbon cycling is limited.…”