Sardine spawning off the European Atlantic coast: Characterization of and spatio-temporal variability in spawning habitat

Bernal, M.; Stratoudakis, Yorgos; Coombs, S. H.; Angélico, Maria Manuel; Lanzós, A. Lago de; Porteiro, Carmela; Sagarmínaga, Yolanda; Santos, M.B.; Uriarte, Andrés; Cunha, Eduardo Ribeiro; Valdés, Luis; Borchers, David L.

doi:10.1016/j.pocean.2007.04.018

Cited by 88 publications

(84 citation statements)

References 22 publications

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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 (Sardina pilchardus) 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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Section: Introductionmentioning

confidence: 99%

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

2015

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“…A mismatch between distribution of eggs and adults has also been reported for some areas (Bernal et al 2007, ICES 2016, and may indicate displacement of fish, larvae and/or eggs. The Iberian Poleward Current (IPC), a narrow (25-40 km), slope-trapped, tongue-like structure that flows northerly off the coasts of the Iberian Peninsula and the South of France (de Castro et al 2011), creates favourable conditions for the retention of larvae close to the shelf break (Santos et al 2007).…”

Section: Discussionmentioning

confidence: 74%

“…From the three core-zones in this study, only the Gulf of Cadiz region corresponds to an area of significant spawning preference evidenced by Bernal et al (2007); however this is also the corezone where the lowest values of juveniles were found. Nevertheless, the outcomes of the present study highlight that intermediate egg abundances values foster juvenile sardine presence.…”

Section: Discussionmentioning

confidence: 76%

“…coastal upwelling waters) (Zwolinski et al 2010). Spawning areas have also been described for this area (Bernal et al 2007), but there is limited information regarding the distribution of sardine juveniles (Marques 2005). The only information for this area is their regular presence on the northern Portuguese coastal shelf due to the proximity of the Douro, Ria de Aveiro, Tejo and Sado estuaries (Silva et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Essential habitat for sardine juveniles in Iberian waters

et al. 2017

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Summary: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.Keywords: Portuguese coast; Gulf of Cadiz; acoustic survey; fish habitat; Sardina pilchardus; juveniles; fisheries management. Hábitat esencial para los juveniles de sardina en aguas IbéricasResumen: En un periodo de mínimo histórico para el stock de sardina ibérica, el conocimiento de la distribución de los juveniles de sardina resulta crucial para el desarrollo de estrategias de gestión pesquera. Se usaron modelos aditivos generalizados para relacionar la presencia de los juveniles de sardina con las variables geográficas y las principales zonas de desove (abundancia de huevos) y a su vez para relacionar la abundancia de los juveniles con las condiciones ambientales adyacentes. Se identificaron tres zonas centrales: la plataforma norte portuguesa (centrada enfrente de la localidad de Aveiro), la zona costera próxima al estuario del Tajo y la parte este del golfo de Cádiz. Las diferencias espaciales encontradas en la relación entre la presencia de juveniles y la abundancia de huevos sugieren que el hábitat esencial de los juveniles puede diferir parcialmente de las zonas de desove existentes. Los modelos también señalaron relaciones significativas entre la abundancia de juveniles, la temperatura, y las variables geográficas combinadas con la salinidad en el oeste y con el zooplancton en el sur. Los resultados indican que la distribución de los juveniles de sardina a lo largo de las aguas de la Península Ibérica resulta de la combinación de procesos dinámicos que se dan en edades tempranas, cómo la retención de huevos y larvas, una mortalidad reducida y zonas de nutrición con condiciones favorables tanto para larvas cómo para juveniles.Palabras clave: costa portuguesa; golfo de Cádiz; campaña acústica; hábitat de peces; Sardina pilchardus; juveniles; gestión ...

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“…There is considerable previous research analysing ichthyoplankton samples for characterization of spawning habitat in order to better understand the ecological context of spawning (Bernal et al 2007, Stratoudakis et al 2003. However, the adult samples in routine DEPM applications are usually only used for estimating the daily fecundity in order to obtain the spawning stock biomass.…”

Section: Discussionmentioning

confidence: 99%

Modelling the spatio-temporal distribution of age-1 Bay of Biscay anchovy (Engraulis encrasicolus) at spawning time

et al. 2013

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SUMMARY: To efficiently manage and maintain fish stock abundance and age structure, it is necessary to understand variability in its spatial distribution. The main objective of this study was to describe the demographic structure of the Bay of Biscay anchovy during the main spawning period based on adult samples from 15 daily egg production method surveys. The proportion of age-1 individuals was modelled using generalized additive models with a binomial distribution and a logit link in relation to geographical and environmental covariates. The possibility of obtaining different models depending on the average age-1 proportion (low or high) was also explored. In general, age-1 individuals were found in shallow waters close to the coast, especially associated with the Gironde and Adour river plumes, whereas older individuals were prevalent on the shelf break and in oceanic waters. However, in years with a high age-1 proportion the younger individuals were also dominant in oceanic waters. These results could be used for management purposes, such as defining protected areas for particular age groups.Keywords: spatial age composition, anchovy, Bay of Biscay, daily egg production method, generalized additive model, environmental effects.RESUMEN: Distribución espacio-temporal de la edad 1 de anchoa del golfo de Bizkaia (Engraulis Encrasicolus) en el momento de puesta. -Con el fin de gestionar eficientemente la abundancia y la estructura espacial de un stock es necesario entender su distribución espacial. El objetivo principal de este trabajo es describir la estructura demográfica de la anchoa del golfo de Bizkaia durante el periodo de desove a partir de las muestras de adultos recogidas en 15 campañas del método de producción diaria de huevos. La proporción de individuos de edad 1 se modeló en función de variables geográficas y ambientales por medio de un modelo aditivo generalizado con distribución binomial y función enlace logit. Además se estudió la posibilidad de obtener diferentes modelos dependiendo de si la proporción de edad 1 promedio es baja o alta. En general, los individuos de edad 1 se encontraron en aguas poco profundas cerca de la costa, especialmente en las plumas de los ríos Garona y Adur, mientras que los individuos de mayor edad prevalecieron en el cantil y en aguas oceánicas. Sin embargo, los años con una alta proporción de edad 1, los individuos jóvenes fueron también predominantes en aguas oceánicas. Estos resultados podrían utilizarse para fines relacionados con la gestión, tales como la definición de áreas protegidas para determinados grupos de edad.Palabras clave: composición de edad espacial, anchoa, golfo de Bizkaia, método de producción diaria de huevos, modelo aditivo generalizado, efectos ambientales.

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Sardine spawning off the European Atlantic coast: Characterization of and spatio-temporal variability in spawning habitat

Cited by 88 publications

References 22 publications

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

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

Essential habitat for sardine juveniles in Iberian waters

Modelling the spatio-temporal distribution of age-1 Bay of Biscay anchovy (<i>Engraulis encrasicolus</i>) at spawning time

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