Sex dimorphism in European sea bass (Dicentrarchus labrax L.): New insights into sex-related growth patterns during very early life stages

Type Article
Date 2021-04
Language English
Author(s) Faggion SaraORCID1, Vandeputte MarcORCID2, Vergnet Alain1, Clota Frederic2, Blanc Marie-Odile1, Sanchez Pierre2, Ruelle Francois1, Allal FrancoisORCID1, Wang Hanping1
Affiliation(s) 1 : MARBEC, CNRS, Ifremer, IRD, Univ Montpellier, Palavas-les-Flots, France
2 : MARBEC, CNRS, Ifremer, IRD, Univ Montpellier, Palavas-les-Flots, France, INRAE, AgroParisTech, GABI, Université Paris-Saclay, Jouy-en-Josas, France
Source PLOS ONE (1932-6203) (Public Library of Science (PLoS)), 2021-04 , Vol. 16 , N. 4 , P. e0239791 (14p.)
DOI 10.1371/journal.pone.0239791
Abstract

The European sea bass (Dicentrarchus labrax) exhibits female-biased sexual size dimorphism (SSD) early in development. New tagging techniques provide the opportunity to monitor individual sex-related growth during the post-larval and juvenile stages. We produced an experimental population through artificial fertilization and followed a rearing-temperature protocol (~16°C from hatching to 112 days post-hatching, dph; ~20°C from 117 to 358 dph) targeting a roughly balanced sex ratio. The fish were tagged with microchips between 61 and 96 dph in five tagging trials of 50 fish each; individual standard length (SL) was recorded through repeated biometric measurements performed between 83 to 110 dph via image analyses. Body weight (BW) was modelled using the traits measured on the digital pictures (i.e. area, perimeter and volume). At 117 dph, the fish were tagged with microtags and regularly measured for SL and BW until 335 dph. The experiment ended at 358 dph with the sexing of the fish. The sex-ratio at the end of the experiment was significantly in favor of the females (65.6% vs. 34.4%). The females were significantly longer and heavier than the males from 103 dph (~30 mm SL, ~0.44 g BW) to 165 dph, but the modeling of the growth curves suggests that differences in size already existed at 83 dph. A significant difference in the daily growth coefficient (DGC) was observed only between 96 and 103 dph, suggesting a physiological or biological change occurring during this period. The female-biased SSD pattern in European sea bass is thus strongly influenced by very early growth differences between sexes, as already shown in previous studies, and in any case long before gonadal sex differentiation has been started, and thus probably before sex has been determined. This leads to the hypothesis that early growth might be a cause rather than a consequence of sex differentiation in sea bass.

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Publisher's official version 14 952 KB Open access
S1 Fig. Image analysis to recover length, height, perimeter and area of the fish. 1 48 KB Open access
S2 Fig. Determination of the sex of the fish. 1 70 KB Open access
S3 Fig. Regression between measured and estimated values of fish body weight using the model (1) for the “model set” (blue circles) and the “validation set” (red triangles). 1 183 KB Open access
S4 Fig. Regression between logarithm of the measured standard length and logarithm of the measured body weight. 1 183 KB Open access
S5 Fig. Regression between logarithm of measured and estimated values of fish standard length using the model (2) for the “model set” (blue circles) and the “validation set” (red triangles). 1 148 KB Open access
S1 Table. Prediction of body weight from digital picture measurements and prediction of standard length. 1 96 KB Open access
S2 Table. Coefficient of determination (R2) and Akaike information criterion (AIC) for models of multiple regression to estimate body weight. 1 96 KB Open access
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How to cite 

Faggion Sara, Vandeputte Marc, Vergnet Alain, Clota Frederic, Blanc Marie-Odile, Sanchez Pierre, Ruelle Francois, Allal Francois, Wang Hanping (2021). Sex dimorphism in European sea bass (Dicentrarchus labrax L.): New insights into sex-related growth patterns during very early life stages. PLOS ONE, 16(4), e0239791 (14p.). Publisher's official version : https://doi.org/10.1371/journal.pone.0239791 , Open Access version : https://archimer.ifremer.fr/doc/00691/80288/