scholarly journals Trophic ecology of European sardine Sardina pilchardus and European anchovy Engraulis encrasicolus in the Bay of Biscay (north-east Atlantic) inferred from δ13C and δ15N values of fish and identified mesozooplanktonic organisms

2014 ◽  
Vol 85 ◽  
pp. 277-291 ◽  
Author(s):  
T. Chouvelon ◽  
A. Chappuis ◽  
P. Bustamante ◽  
S. Lefebvre ◽  
F. Mornet ◽  
...  
2009 ◽  
Vol 66 (10) ◽  
pp. 2176-2182 ◽  
Author(s):  
Iratxe Zarraonaindia ◽  
Miguel Angel Pardo ◽  
Mikel Iriondo ◽  
Carmen Manzano ◽  
Andone Estonba

Abstract Zarraonaindia, I., Pardo, M. A., Iriondo, M., Manzano, C., and Estonba, A. 2009. Microsatellite variability in European anchovy (Engraulis encrasicolus) calls for further investigation of its genetic structure and biogeography. – ICES Journal of Marine Science, 66: 2176–2182. Attention to genetic and ecological perspectives can enhance strategies for using fishery resources sustainably. A potentially important application is the use of molecular markers to assess the genetic stock structure of a harvested species. In this study, seven microsatellite markers were analysed in anchovy samples from the Bay of Biscay, the Gulf of Cádiz, and the Gulf of Lions to assess the genetic structure of anchovy (Engraulis encrasicolus) populations in the Bay of Biscay and to infer the biogeographic origin of these populations. All samples showed a deficit of heterozygotes that could be explained by non-random mating, Wahlund's effect, and especially by the presence of null alleles. Global FST and RST values, uncorrected and corrected for null alleles, were significant. There was significant genetic heterogeneity between two populations in the Bay of Biscay, suggesting that anchovy there may not be panmictic. Moreover, the results reinforce the hypothesis of a recent common ancestor shared by Bay of Biscay and western Mediterranean anchovy. These results, together with those of earlier studies, suggest merit in further investigating spatio-temporal genetic variation among anchovy populations in the Northeastern Atlantic.


2008 ◽  
Vol 65 (11) ◽  
pp. 2444-2453 ◽  
Author(s):  
Youen Vermard ◽  
Paul Marchal ◽  
Stéphanie Mahévas ◽  
Olivier Thébaud

The scope of this paper is to describe, evaluate, and forecast fishing trip choices of the Bay of Biscay pelagic fleet using random utility modeling (RUM). First, alternative fishing trip choices of this fleet were identified using multivariate statistical methods based on species landings weighted by value and defined as distinct fishing activity or fisheries (termed métiers). A RUM was specified, which included trip components as attributes during the period 2001–2004 (a lagged percentage of the value per unit of effort of the main species caught, total value per unit of effort, and inertia in terms of changes from one métier to another). For the main métiers, the proportion of correct effort allocation is 90% during the calibration period of 2001–2004. The results from the RUM are used to parameterize a simulation model of trip choice. The model is used to predict trip choices in 2005, throughout most of which fishing was constrained by the closure of the European anchovy (Engraulis encrasicolus) fishery. Simulation results are compared with observed trip choices following the fishing ban: 80% of observed trip choices are correctly predicted by the model. The capacity of the behavioral model to predict responses to the closure is then discussed.


2010 ◽  
Vol 67 (8) ◽  
pp. 1574-1586 ◽  
Author(s):  
M. Pilar Tugores ◽  
Magdalena Iglesias ◽  
Núria Díaz ◽  
Dolores Oñate ◽  
Joan Miquel ◽  
...  

Abstract Tugores, M. P., Iglesias, M., Díaz, N., Oñate, D., Miquel, J., and Giráldez, A. 2010. Latitudinal and interannual distribution of the European anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) in the western Mediterranean, and sampling uncertainty in abundance estimates. – ICES Journal of Marine Science, 67: 1574–1586. On the Spanish Mediterranean continental shelf, late-autumn echo-integration acoustic surveys have been performed annually since the 1990s. The surveys coincide with the recruitment season of anchovy (Engraulis encrasicolus) and the start of the spawning season of sardine (Sardina pilchardus), and they provide estimates of stock size for the main fisheries in the area. Latitudinal distribution of the abundance of the two species from 2003 till 2006 is evaluated, and transitive geostatistical techniques applied to estimate the sampling uncertainty of the overall abundance estimate. The anchovy stock was found mainly in areas influenced by river run-off, in well-known anchovy spawning areas, suggesting that anchovy remained on their spawning grounds until late autumn or that survival was higher in these regions of enhanced productivity. By the time of the surveys, sardine were already occupying their spawning grounds over the continental shelf. The precision of the abundance estimates was generally high. The few cases of low precision were re-examined and found to stem most probably from processing errors, so the re-examination has contributed to an improvement in the accuracy of the estimates. The greater precision obtained in the southern subarea suggested a greater homogeneity in the spatial distribution of both species.


Author(s):  
Tanju Mutlu

The aim of this study is to determine the stable isotope ratios of anchovy caught in the Black Sea and Marmara Sea. Stable carbon and nitrogen isotope ratios (δ13C, δ15N) of European anchovy (Engraulis encrasicolus) were estimated at four sampling sites (İğneada, İstanbul, Trabzon and Hopa) in the Black Sea and Marmara Sea (Turkey). δ13C and δ15N values of European anchovy ranged from -22.31 to -19.19 ‰ and from 3.81 to 12.79 ‰, while C/N ratios ranged from 2.01 to 6.21 in muscle tissue of European anchovy, respectively. İğneada station had more depleted δ13C values and more enriched δ15N values than other stations. This difference might be due to the terrestrial input and agricultural activities in this region.


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