Impact of a winter upwelling event on the distribution and transport of sardine (Sardina pilchardus) eggs and larvae off western Iberia: a retention mechanism

Santos, A. Miguel P.; Peliz, Álvaro; Dubert, Jesús; Oliveira, Paulo B.; Angélico, Maria Manuel; Ré, Pedro

doi:10.1016/j.csr.2003.10.004

Cited by 161 publications

(128 citation statements)

References 16 publications

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“…Several works have suggested the existence of some mechanism that might aVect the larval dispersion in Aveiro (Santos et al 2004(Santos et al , 2007Peliz et al 2007). Santos et al (2007) found that the upwelling events could signiWcantly change the distribution of early larval stages of Sardina pilchardus, and Peliz et al (2007) working with a dispersal model for larvae crab obtained a good Wt between the release of Xoats from Aveiro and a large part of the Xoats retained in the shelf zone near the emission points.…”

Section: Discussionmentioning

confidence: 99%

Strong genetic differentiation among east Atlantic populations of the sword razor shell (Ensis siliqua) assessed with mtDNA and RAPD markers

et al. 2010

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The sword razor shell Ensis siliqua (Linnaeus, 1758) is a bivalve with a high commercial value being appreciated in fresh and processed markets. However, the genetic studies carried out in populations of E. siliqua are scarce. In this work, the genetic variability and diVerentiation of the sword razor shell was assessed using PCRRFLPs of a fragment of the 16S rRNA mitochondrial gene and random ampliWed polymorphic loci (RAPD) in nine localities from Ireland, Spain, and Portugal. In the 314 individuals examined for the mitochondrial fragment, 12 composite haplotypes were observed; meanwhile, a unique phenotype was observed for each of the 242 individuals analyzed with 61 RAPD loci. Two of the mitochondrial composite haplotypes accounted for the majority of individuals (89.81%) and showed a remarkably disjoint distribution between Irish and Iberian samples, with the exception of Aveiro which exhibited as the most frequent haplotype the same found in Ireland. The level of variability observed for each sample was generally correlated with both types of markers and the results obtained suggest the existence of a strong population diVerentiation between Irish and Iberian localities, except for the Portuguese sample from Aveiro which is surprisingly closer to Irish individuals, although it is probably highly diVerentiated.

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Section: Discussionmentioning

confidence: 99%

Strong genetic differentiation among east Atlantic populations of the sword razor shell (Ensis siliqua) assessed with mtDNA and RAPD markers

et al. 2010

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“…The northwest Portuguese waters encompass the main nursery area of the Iberian Peninsula sardine stock (Silva et al 2009, ICES 2014. The concentration of juvenile fish in the area appears to result from the combination of retention mechanisms and high productivity associated with upwelling and river runoff (Álvarez and Alemany 1997, Santos et al 2004, Bernal et al 2007). Like most small pelagic fishes, sardine recruitment fluctuates extensively between years, partly driven by environmental conditions (Santos et al 2012 and references therein).…”

Section: Introductionmentioning

confidence: 99%

Predicting the age of sardine juveniles (<em>Sardina pilchardus</em>) from otolith and fish morphometric characteristics

2015

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Summary: An age prediction model based on individual morphometric characteristics (total length; weight) and otolith morphometric characteristics (diameter; weight) was investigated for juvenile sardine, Sardina pilchardus (Walbaum, 1792). Juveniles were collected from northern Portugal between May 2004 and January 2005. Daily growth rings were counted on the otoliths of 114 juveniles of 7-16 cm total length. The sample was divided into a training sample used to develop the age prediction model and a test sample used to evaluate the predictive ability of the model. The best model for predicting the logarithm of age was a linear regression with otolith diameter. The prediction of daily age was more accurate for younger (<200 days) juveniles. Overall, ages predicted from the model were unbiased in relation to ages determined from otolith microincrement counts. Moreover, predicted daily ages reproduced the overall shape of the observed age distribution and provided comparable growth estimates (0.041 cm day -1 ). The back-calculated birthdate period ranged from 29 September 2003 to 22 July 2004, with a peak in January 2004, which is consistent with the spawning season. The model presented here could be used as a method for increasing the volume of juvenile daily age data. Since growth and survival varies spatially and temporally, relationships between age and otolith/fish morphometry should not be extrapolated outside sampled periods, areas and fish size/age.

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“…The above examples show that the presence of MW eddies is responsible for the large offshore excursion of some of the upwelling filaments generated in the area and that these have no need for strong wind forcing. Although considered as a typical summer phenomenon, wind-induced upwelling along the Portuguese coast can occur sporadically in winter (Fiúza, 1982;Haynes et al, 1993;Santos et al, 2004). The winter development of an extremely long filament (about 400 km) off the Portuguese west coast, as reported by Peliz et al (2004) using satellite data, could not be related to wind-driven dynamics since the winds were from southwest.…”

Section: Relation Between Model Mw Properties and Surface Variablesmentioning

confidence: 89%

Surface expression of Mediterranean Water dipoles and their contribution to the shelf/slope – open ocean exchange

2010

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Abstract. The generation of dipolar eddies within the Mediterranean Water (MW) layers, at the Portuguese continental slope, was observed using subsurface RAFOS floats. The surface expression of these mid-depth dipoles is here characterized with remote sensing data, namely with sea surface temperature, chlorophyll concentration and sea surface height measurements. Two cases are presented demonstrating the remote detection of these underwater structures in the Gulf of Cadiz during 1998 and 2001. The presence of subsurface MW dipoles in the Iberian coastal zone is shown to influence the development of coastal upwelling filaments. The surface circulation induced by the dipoles causes the upwelling filaments to extend offshorewards and thus to enhance the transport of physical, chemical and biological properties into the open ocean. A numerical model simulation of the ocean circulation around the Iberian Peninsula forced by heat and freshwater fluxes (computed using the NCEP reanalysis atmospheric state) and by the overflow of MW at the Strait of Gibraltar, corroborates the connection between the surface and the mid-depth flows. The highresolution numerical experiment is used to help clarifying the occurrence of the MW dipoles surface expression and the impact of these dipoles on the eddy kinetic energy of the upper ocean and on the exchange of volume and salt between the shelf/slope and the open ocean.

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Impact of a winter upwelling event on the distribution and transport of sardine (Sardina pilchardus) eggs and larvae off western Iberia: a retention mechanism

Cited by 161 publications

References 16 publications

Strong genetic differentiation among east Atlantic populations of the sword razor shell (Ensis siliqua) assessed with mtDNA and RAPD markers

Strong genetic differentiation among east Atlantic populations of the sword razor shell (Ensis siliqua) assessed with mtDNA and RAPD markers

Predicting the age of sardine juveniles (<em>Sardina pilchardus</em>) from otolith and fish morphometric characteristics

Surface expression of Mediterranean Water dipoles and their contribution to the shelf/slope – open ocean exchange

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