Iberian Sardine Research Articles

What drives the recruitment of European sardine in Atlanto-Iberian waters (SW Europe)? Insights from a 22-year analysis

The European sardine (Sardina pilchardus) is the most abundant and socio-economically important small pelagic fish species in Western Iberia Upwelling Ecosystem. As a result of a long series of low recruitments, sardine biomass off Western Iberia has greatly reduced since the 2000s. Recruitment of small pelagic fish is mainly dependent on environmental factors. In order to identify the key drivers of sardine recruitment, it is essential to understand its temporal and spatial variability. To achieve this goal, a comprehensive suite of atmospheric, oceanographic, and biological variables spanning 1998–2020 (22 years) were extracted from satellite datasets. These were then related to in situ recruitment estimates obtained from yearly spring acoustic surveys carried out along two different hotspots of sardine recruitment of the southern Iberian sardine stock (NW Portugal and Gulf of Cadiz). Sardine recruitment in Atlanto-Iberian waters appears to be driven by distinct combinations of environmental factors, although sea surface temperature was identified as the main driver in both regions. Physical conditions that favour larval feeding and retention, such as shallower mixed layers and onshore transport, were also seen to play a vital role in modulating sardine recruitment. Furthermore, high sardine recruitment in NW Iberia was associated with optimal conditions in the winter (January–February). In contrast, recruitment strength of sardine off the Gulf of Cadiz were associated with the optimal conditions during late autumn and spring. The results from this work provide valuable insights to further understand the dynamics of sardine off Iberia, with potential to contribute to the sustainable management of sardine stocks in Atlanto-Iberian waters, particularly under climate change.

Predictions of sardine and the Portuguese continental shelf ecosystem dynamics under future fishing, forced-biomass and SST scenarios

We used the Ecopath with Ecosim ecosystem model to assess the future effects of multiple stressors on sardine and the Portuguese continental shelf ecosystem. We assessed individual and combined impacts of changes in sardine fishing pressure, biomass of sardine competitors and predators and sea surface temperature (SST). This study demonstrated that the greatest impact on sardine stock is caused by projected SST rise whose effect is dominant and detrimental to sardine stock regardless of other conditions, including sardine fishing at maximum sustainable yield (FMSY). The largest impact on ecosystem stability, maturity and diversity of flows was observed under the forced-biomass scenarios that simulate changes in biomass of sardine predators and competitors. Moreover, these stressors alongside FMSY are projected to play an important role in the future evolution of the sardine stock. Results presented in this study can assist long-term and strategic management of the Iberian sardine stock.

Delayed predator-prey collapses: the case of black-legged kittiwakes and Iberian sardines

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 631:201-207 (2019) - DOI: https://doi.org/10.3354/meps13164 Delayed predator-prey collapses: the case of black-legged kittiwakes and Iberian sardines A. Martínez-Abraín1,*, P. Santidrián Tomillo2, J. Mouriño3, S. Tenan4, D. Oro5,6 1Universidade da Coruña, Facultad de Ciencias, Evolutionary Biology Group, Campus da Zapateira s/n, 15071 A Coruña, Spain 2The Leatherback Trust, Goldring-Gund Marine Biology Station, Playa Grande, Costa Rica 3Arcea, Xestión de Recursos Naturais S.L., Velázquez Moreno 9, oficina 305, 36201 Vigo, Spain 4MUSE - Museo delle Scienze, Sezione di Zoologia dei Vertebrati, Corso del Lavoro e della Scienza, 3, 38122 Trento, Italy 5Instituto Mediterráneo de Estudios Avanzados IMEDEA (CSIC-UIB), Miquel Marquès 21, 07190 Esporles, Spain 6Centre d’Estudis Avançats de Blanes CEAB (CSIC), Acces Cala Sant Francesc 14, 17300 Blanes, Spain *Corresponding author: a.abrain@udc.es ABSTRACT: We analysed the long-term (1975-2017) population response of a colony of a marine top predator, the black-legged kittiwake Rissa tridactyla, to the population dynamics of sardine Sardina pilchardus, its main local prey. The study site (Sisargas Islands, Spain) is located at the southernmost edge of the geographical distribution of the predator. Kittiwake counts of breeding pairs started with the discovery of the colony (1975), likely close to the actual year of first colonization. Sardine landings by age class (1978-2016) were taken from the International Council for the Exploration of the Sea (ICES) database. Sequential t-test analysis revealed that a regime shift of the oldest sardine age class (age 6+) took place in 1991 and that kittiwakes experienced a regime shift in the number of breeding pairs in 1993, 2 yr after the prey shift. Multiple autocorrelation functions for the detrended time series of sardines and kittiwakes indicated an autocorrelation with a time lag of 2 yr. Despite much reduced fishing effort, sardine densities have not recovered since the collapse, likely due to changes in large-scale atmospheric circulation in the Northern Hemisphere in the late 1990s. Kittiwakes at Sisargas have not recovered demographically, remaining nearly extinct during the last ca. 20 yr. Although we lack detailed demographic data for the studied kittiwake population, we suggest that massive breeding failure and subsequent dispersal to higher-quality patches might explain the rapid non-linear collapse in breeding population density. We discuss some behavioural social responses that may have occurred during and after the collapse to explain the dynamics of the study colony. KEY WORDS: Population crash · Black-legged kittiwakes · Time delay · Non-linearities · Predator-prey dynamics · Food availability · Iberian sardine · Fisheries collapse Full text in pdf format Supplementary material PreviousNextCite this article as: Martínez-Abraín A, Santidrián Tomillo P, Mouriño J, Tenan S, Oro D (2019) Delayed predator-prey collapses: the case of black-legged kittiwakes and Iberian sardines. Mar Ecol Prog Ser 631:201-207. https://doi.org/10.3354/meps13164 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 631. Online publication date: November 21, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Study of sardine (Sardina pilchardus) regime shifts in the Iberian Atlantic shelf waters

AbstractSardine fisheries in the Iberian Atlantic shelf (36°N–44.5°N) show decadal‐scale cycles. In the late 1990s, a positive phase in sardine stock was expected; on the contrary, catches have declined until now. Regime shifts in climatic and oceanographic variables on different scales (as forcing factor) and shifts in sardine stock (as result) have been used with the aim of identifying the physical variables that explain most of the sardine population variance in the region. Circa 1998, when last sardine regime shift was detected, the main patterns of large‐scale atmospheric circulation in the Northern Hemisphere with influence in the study area namely Northern Atlantic Oscillation (NAO) and East Atlantic (EA) pattern changed and coupled in a combination that led to a rise in sea surface temperature and a decline in the coastal upwelling intensity. Several years with a downwelling situation in average in the main spawning and feeding Iberian sardine areas would have affected the stock abundance, averting the return to the projected positive regime. The sardine negative regime shift was detected first in the regions of the study located further north. The regional variable latent heat flux that groups a set of environmental processes related to the ocean–atmosphere heat exchanges and so with the turbulence manages to explain the 72% of sardine recruitment.

Essential habitat for sardine juveniles in Iberian waters

In a period when the Iberian sardine stock abundance is at its historical minimum, knowledge of the sardine juvenile’s distribution is crucial for the development of fishery management strategies. Generalized additive models were used to relate juvenile sardine presence with geographical variables and spawning grounds (egg abundance) and to model juvenile abundance with the concurrent environmental conditions. Three core areas of juvenile distribution were identified: the Northern Portuguese shelf (centred off Aveiro), the coastal region in the vicinity of the Tagus estuary, and the eastern Gulf of Cadiz. Spatial differences in the relationship between juvenile presence and egg abundances suggest that essential juvenile habitat might partially differ from the prevailing spawning grounds. Models also depicted significant relationships between juvenile abundance, temperature and geographical variables in combination with salinity in the west and with zooplankton in the south. Results indicate that the sardine juvenile distribution along the Iberian Peninsula waters are an outcome of a combination of dynamic processes occurring early in life, such as egg and larva retention, reduced mortality and favourable feeding grounds for both larvae and juveniles.

A biophysical model for simulating early life stages of sardine in the Iberian Atlantic stock

The Iberian sardine (Sardina pilchardus) is a traditional fishery in western Iberia that is economically important in Portugal and in Galicia (NW Spain). The International Council for the Exploration of the Seas (ICES) advice for the sardine in regions VIII and IXa in 2013 indicated that the biomass has decreased since 2006 and recruitment has been below the long term average since 2005. Recruitment is very variable, so it is important to understand the underlying processes driving this variation in order to manage the fishery effectively. In this study, a biophysical model was used to simulate the early life (egg and larval) stages of sardine. A high resolution hydrodynamic model for North and Northwest Iberia was used to force a Lagrangian Individually-Based Model (IBM) that simulated advection and dispersion (both horizontal and vertical) and included some biological behaviour. A Lower Trophic Level (LTL) model coupled to the hydrodynamic model was also used to get some insight on recruitment for years 2006–2007. Additionally, since in this area there are two different spawning grounds that could be associated with two eventually different populations, we have tried to show how the model can be used for giving insight on stock connectivity and therefore can contribute to stock delineation.

Endogenous Fishery Management in a Stochastic Model: Why Do Fishery Agencies Use TACs Along with Fishing Periods?

This paper seeks to explain the circumstances under which using total allowable catch (TAC) as an instrument to manage a fishery along with fishing periods may be of interest from a regulatory point of view. The deterministic analysis by Homans and Wilen (J Environ Econ Manag 32:1–21, 1997) and Anderson (Ann Oper Res 94:231–257, 2000) is thus extended to a stochastic scenario where the resource cannot be measured accurately. The resulting model is solved numerically to find the optimal control rules in the Iberian sardine stock. Three relevant conclusions can be highlighted from simulations: first, the greater the uncertainty regarding the state of the stock, the lower the probability of the fishery being closed before the end of the fishing period. Second, the use of TACs as a management instrument in fisheries that are already regulated by fishing periods leads to: (i) an increase in the optimal season length and harvests, especially for medium and high numbers of licences; (ii) improved biological and economic variables when the fleet is large; and (iii) extinction risk for the resource being eliminated. Third, the regulator would rather select the number of licences than restrict the season length.

Cycles, trends, and residual variation in the Iberian sardine (Sardina pilchardus) recruitment series and their relationship with the environment

Abstract Santos, M. B., González-Quirós, R., Riveiro, I., Cabanas, J. M., Porteiro, C., and Pierce, G. J. 2012. Cycles, trends, and residual variation in the Iberian sardine (Sardina pilchardus) recruitment series and their relationship with the environment. – ICES Journal of Marine Science, 69: 739–750. Recruitment variability is an important component of the dynamics of Iberian sardine (Sardine pilchardus). Since 2006, poor recruitment has led to a decrease in stock biomass, the latest in a series of such crises for sardine fisheries. Understanding the mechanisms behind recruitment fluctuations has been the objective of many previous studies, and various relationships between recruitment and environmental variables have been proposed. However, such studies face several analytical challenges, including short time-series and autocorrelated data. A new analysis of empirical relationships with environmental series is presented, using statistical methods designed to cope with these issues, including dynamic factor analysis, generalized additive models, and mixed models. Relationships are identified between recruitment and global (number of sunspots), regional (NAOAutumn), and local [winter wind strength, sea surface temperature (SST), and upwelling] environmental variables. Separating these series into trend and noise components permitted further investigation of the nature of the relationships. Whereas the other three environmental variables were related to the trend in recruitment, SST was related to residual variation around the trend, providing stronger evidence for a causal link, possible mechanisms for which are discussed. After the removal of trend and cyclic components, residual variation in recruitment is also weakly related to the previous year's spawning-stock biomass.

On the dynamics of Sardina pilchardus: orbits of stability and environmental forcing

Abstract Solari, A. P., Santamaría, M. T. G., Borges, M. F., Santos, A. M. P., Mendes, H., Balguerías, E., Díaz Cordero, J. A., Castro, J. J., and Bas, C. 2010. On the dynamics of Sardina pilchardus: orbits of stability and environmental forcing. – ICES Journal of Marine Science, 67: 1565–1573. The dynamics of Sardina pilchardus in Iberian upwelling are examined. Spawning-stock biomass (SSB), recruitment (R), and production (R/SSB) data for the years 1978–2006 are analysed in relation to the upwelling index (UPW) and sea surface temperature (SST). The population oscillates in two relatively stable orbits (identified by multiresolution decomposition of the recruitment series) because the external forcing (UPW and SST) are the inverse of each other and the synchrony is lost between the two external variables, R and R/SSB as they shift towards steep, negative (depensatory) trends. Such mechanics may have induced recruitment failures and significant decreases in abundance of Iberian sardine. The relationships are assumed to validate a complex and dynamic continuum (multiple orbits of stability) and an alternative variable-carrying-capacity population model. Radial systems with two orbits of stability are proposed for the R/SSB and S/SSB (where S is the stock size) relationships. Results are discussed in relation to classical and alternative SR models to address stock rehabilitation and fishing mortality issues as the population shifts towards low recruitment and abundance, and critical factors to consider in developing exploitation strategies for systems with multiple orbits of stability are discussed.

New insights into the early life ecology of <em>Sardina pilchardus</em> (Walbaum, 1792) in the northern Iberian Atlantic

In the Atlantic Iberian estuaries, sardines tend to be a minor component of the ichthyoplankton assemblages, with rare occurrence largely restricted to estuarine mouths. However, this was not the case of the Lima estuary (NW Portugal), where sardines were the most abundant and frequently occurring marine taxon of the larval fish assemblages. Abundance of sardines collected during a two-year survey (2002-2004) ranged from 0.5 to 60.8 larvae/100 m3, with the majority still showing yolk and unpigmented eyes. Moreover, 80% of sardines were 8 days old or less and the total length ranged from 2 to 16 mm. Seasonal variations of sardine occurrence in the Lima estuary correlated with temporal variations of salinity and temperature in the water column. The unusually high river-flow observed during the winter of 2002-2003, which preceded the spring-summer abundance peak, seemed to act as a signal for the estuarine recruitment that was encountered. In addition, the estuarine occurrence of sardine larvae was also correlated with the intensity of summer upwelling, which was responsible for coastal depletion of sardine larvae resulting in estuarine low catches during the summer of 2002. The Lima estuary also revealed another peculiarity related to the lack of temporal synchrony between coastal spawning activity and occurrence of larvae within the estuary. The abundance peaks of newly-hatched larvae (autumn 2002 and spring-summer 2003) did not coincide with the winter-spring spawning pattern described earlier for the northern Iberian coast. Modifications of the spawning strategy of the northern Iberian sardine stock are discussed based on these new insights into the early life of S. pilchardus .

Geographic variability of sardine dynamics in the Iberian Biscay region

Abstract Silva, A., Skagen, D. W., Uriarte, A., Massé, J., Santos, M. B., Marques, V., Carrera, P., Beillois, P., Pestana, G., Porteiro, C., and Stratoudakis, Y. 2009. Geographic variability of sardine dynamics in the Iberian Biscay region. – ICES Journal of Marine Science, 66: 495–508. The spatio-temporal variability in the distribution, demographic structure, recruitment, and mortality of sardine within the Iberian Biscay region is described using area-disaggregated data collected during acoustic surveys and at ports since the mid-1980s. Multiple regression models were used to describe log numbers-at-age obtained annually in ten areas covered by three surveys to test the existence of geographic differences in selectivity-at-age, recruitment strength, and mortality and to infer plausible migration routes. Within Iberian waters, sardine biomass was mainly concentrated off western Portugal and the Gulf of Cadiz. In the Bay of Biscay, biomass levels were comparable with those off western Portugal. Recruitment was localized in a few areas (northern Portugal and the Gulf of Cadiz and Bay of Biscay), intermingling with areas dominated by older fish. Recruitment was generally asynchronous among areas, although some recruitment peaks were noticeable across wider regions. Spatial patterns related to strong and weak year classes and year-class slopes were also noted. Clearly distinct dynamics were not evidenced within the Atlanto–Iberian sardine stock area, but the validity of the northern limit was questioned by the connection between sardine dynamics in the Bay of Biscay and the Cantabrian Sea. The results provided some evidence consistent with the hypothesis of sardine movement from recruiting grounds to areas farther along the coast as they grow.

Use of late ovarian atresia in describing spawning history of sardine, Sardina pilchardus

We investigated and compared the pattern of accumulation of recent and late atretic follicles in the ovaries of Iberian sardine, Sardina pilchardus, in relation to body size with the aim to examine whether late atresia can be used in back-calculations of individual spawning history. Oppositely to earlier stages, late atresia in sardine was shown to accumulate even at peak spawning periods in fish of larger size/age indicating a relationship between atretic intensity and the distant reproductive performance of the individuals. Despite the fact that intensity of late atresia was very high in some occasions, its accumulation was not shown to impede imminent spawning activity. Lack of dependence between imminent spawning activity and the intensity of late atresia was related to the differential pattern with which postovulatory and atretic follicles are associated to the lamellar epithelium of the ovary. Finally, the effect of the ‘reference trap’ which is a major source of bias when quantifying structures in stereological measurements, could be mediated or even completely removed by using a measure of ovarian growth, such as gonosomatic index in the present study, as a covariate when modeling variability in the intensity of atresia.

Spatio-temporal variability in fatty acid trophic biomarkers in stomach contents and muscle of Iberian sardine (Sardina pilchardus) and its relationship with spawning

Temporal variation in the fatty acid (FA) composition of stomach contents of Iberian sardines was compared to the relative contribution to dietary carbon made by different prey types for fish from two areas off Portugal. The effect of the FA content of the diet on sardine muscle FA composition was also studied, aiming at (1) analysing if FA biomarkers can be used as a complementary technique for the study of sardine diet and (2) to relate spatial and temporal variations of prey FA content with sardine condition and reproduction. Significant spatial differences in the FA composition of sardine diet occurred with concentrations of n-3 polyunsaturated FA, namely eicosapentaenoic acid [EPA, 20:5n-3] and linolenic acid 18:3n-3, being significantly higher in the diet of sardines from the west coast, whilst the diet of sardines from the south coast was richer in monounsaturated fatty acids (MUFA), namely the carnivory biomarker oleic acid 18:1n-9. These results are in agreement with the higher contribution made by diatoms and dinoflagellates to the diet of sardines off the west coast. Spatial variation in sardine dietary FA was also detected in their muscle composition, specifically for EPA, and the eicosapentaenoic/docosahexaenoic acid and (n-3)/(n-6) ratios, which were higher in sardines from the west coast. No difference in FA composition was detected between sexes, and the seasonal variability in sardine total FA concentration was primarily related to the seasonality of spawning. Sardines accumulate high concentrations of FAs during the resting stage of reproduction when the feeding intensity is similar or lower to that observed during the spawning season. Additionally, sardines show a high selective retention of MUFA and polyunsaturated FA (PUFA) throughout the year except at the beginning of the spawning season, when these FAs are largely invested in the formation of the gonads. Therefore, temporal and regional differences of prey environments are strong enough to be reflected in fish body composition, namely on the accumulation of essential FAs, which can have a strong impact on reproduction success for this species.

Using multinomial models to analyse data from Iberian sardine egg incubation experiments: a comparison with traditional techniques

Abstract Bernal, M., Ibaibarriaga, L., Lago de Lanzós, A., Lonergan, M. E., Hernández, C., Franco, C., Rasines, I., Valdés, L., and Borchers, D. L. 2008. Using multinomial models to analyse data from Iberian sardine egg incubation experiments: a comparison with traditional techniques. – ICES Journal of Marine Science, 65: 51–59. Multinomial rather than traditional models were applied to improve data analysis of incubation experiments for Iberian sardine (Sardina pilchardus) eggs. Incubation experiments were carried out in 2002 in the Gulf of Cádiz, southwestern Spain, and data were taken from the literature for the Cantabrian Sea area. Rigorous review of the traditional models revealed shortcomings in the statistical framework for modelling the developmental progression of egg stages as well as a lack of transparency of the inherent assumptions. Multinomial model results show that egg stage duration varies for all stages, with stages 3 and 4 having the shortest duration. Comparison of the results between multinomial and traditional models shows that multinomial models provide improved insight into developmental mechanisms than that can be achieved using traditional models.

Laboratory investigations on the effect of prey size and concentration on the feeding behaviour of Sardina pilchardus

Laboratory experiments were conducted to study the effects of different prey types and concentrations on the feeding behaviour of the Iberian sardine Sardina pilchardus. Known concen- trations of different prey types (both single prey type and a mixture of prey types) were provided to a shoal of sardines acclimated to laboratory conditions and their feeding behaviour was observed. Data on feeding mode choice, feeding selectivity and filtration efficiency were collected, and clear- ance rates for different prey types and sizes were estimated. Sardines use 2 feeding modes and switch between them depending on prey size. Filter-feeding was used to capture prey ≤724 μm and particulate feeding to capture prey ≥780 μm; therefore the feeding mode switch occurs within these limits. Sardines are able to feed on nanoplankton and can retain prey items as small as 4 μm, and filtration efficiency increases from 20% at this prey size to close to maximum for prey >200 μm. Sardines show selective feeding, preferentially ingesting fish eggs compared to other prey types (even larger fish larvae) when fed cultured, mixed prey assemblages and selecting copepods and decapods over other zooplankton prey when fed wild-collected, mixed prey assemblages. Clearance rates were generally low compared to other clupeids, arising from the smaller mouth gape and lower swimming speed of this species. Results obtained from this study suggest that filter-feeding is the dominant feeding mode of S. pilchardus and that it is able to efficiently utilize microplankton prey, and corroborate previous dietary studies indicating that small zooplankton and chain-forming diatoms dominated stomach contents.

Solar activity governs abundance of Atlantic Iberian sardine Sardina pilchardus

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 269:297-301 (2004) - doi:10.3354/meps269297 Solar activity governs abundance of Atlantic Iberian sardine Sardina pilchardus Cástor Guisande1, *, Ana Ulla1, Peter Thejll 2 1Facultad de Ciencias, Universidad de Vigo, Lagoas-Marcosende, 36200 Vigo, Spain 2Climate Division, Danish Meteorological Institute, Lyngbyvej 100, 2100 Copenhagen Ø, Denmark *Email: castor@uvigo.es ABSTRACT: Annual sardine Sardina pilchardus landings from 1906 to 2002 off the northwest coast of the Iberian Peninsula vary according to solar activity. When the solar cycle is short, there is a trend towards increasing water transport onshore, which favours larval retention in areas close to the coast and, hence, sardine catches increase. However, when the solar cycle is longer, the trend is toward increasing water transport offshore, carrying eggs and larvae into areas where there is not enough food to survive and, therefore, decreasing sardine catches. These findings reveal the potential importance of solar activity on all biological process affected by coastal upwelling, including pelagic fisheries. KEY WORDS: Climate change · Solar activity · Recruitment · Sardine Full text in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 269. Online publication date: March 25, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.

Effect of climate on recruitment success of Atlantic Iberian sardine Sardina pilchardus

The aim of this study was to determine how climatic (North Atlantic Oscillation winter index, NAO, December through March), oceanographic (upwelling intensity, turbulence, water col- umn stability and larval offshore transport) and biotic (adult abundance) factors affect recruitment success of Sardina pilchardus off the northwest coast of the Iberian peninsula. Annual sardine juve- nile landings in the port of Vigo (Spain) from 1980 to 2000 were used as an indicator of sardine recruitment success. Ekman transport along the x-axis (Qx) in February (QxF), from March to April (QxMA), from May to August over the preceding year (QxMJJA), and NAO explained 86% of the variance observed in catches of sardine juveniles. Due to the north-south orientation of the west coast of the Iberian peninsula, upwelling intensity and larval drift offshore are higher the lower the Qx. Landings of sardine juveniles were higher in those years with moderate QxF, high QxMA, low QxMJJA and low NAO values. There was a dome-shaped relationship between sardine juvenile landings and QxF. Under both high and low Qx conditions, the upper layer is strongly mixed. There- fore, the reduced recruitment success observed at both high and low QxF values could be due to a stratified upper layer in February enhancing primary production during the spring bloom and, hence, larval food availability. As March and April are the main spawning periods for sardine in this area, the reduced sardine recruitment success observed as QxMA decreased was probably due to the transport offshore of eggs and larvae. In this area the main upwelling season is from May to August. Therefore, the positive relationship between upwelling intensity from May to August and nutrient concentration in surface layers could explain why landings of sardine were higher when QxMJJA over the preceding year was lower. Finally, in years with low NAO sardine recruitment success was higher. When NAO is lower than average, the winter/spring temperatures are warmer and transport offshore is lower.