DOI: 10.17882/87996
title: Experimental dataset related to the study of the impact of whole-life exposure to ocean acidification on puberty and reproduction of the European sea bass

description: The dataset reported here corresponds to the experimental study aiming at evaluating the impact of whole-life acclimation to different degrees of ocean pH/pCO2 (current condition of the Rade de Brest and predictions of RCP8.5 IPCC scenario by 2050 and by 2100) on the sexual maturation and spawning of a temperate marine teleost, the European sea bass (Dicentrarchus labrax), over two consecutive reproductive cycles.
The hypothesis that severe acidification would lead to the highest impact on plasma sex steroids concentrations and on spawning phenology driving to higher female fecundity was tested. The same physiological traits were monitored during the two first reproductive seasons to estimate the acclimation potential at longer exposition, in pubertal and post-pubertal fish.
In all data sheets, “ID” indicates the identification number of fish and “scenario” the corresponding acidification level. The dataset contains:
- Fulton’s condition factor (K) of females and males in both reproductive seasons individually determined from gametogenesis (November) to spawning season (February to April).
- Female 17β-estradiol (E2) and male 11-keto testosterone (KT) and testosterone (T) plasma concentrations (expressed as ng/ml), during the two reproductive seasons (from gametogenesis (November) to post-spawning season (April)). Sexual steroids concentrations were measured by ELISA with kit from Cayman Chemical (USA, kits # 582701, # 582751, #501890 for testosterone, 11-keto testosterone and 17β-estradiol quantification respectively).
- Proportion of the oocytes at each stages of development (freq) at the beginning of the spawning period (in February and March) of the second reproductive cycle. The classification of stages of oocytes development (stage) followed the criteria previously reported for European sea bass (Mylonas et al. 2003) with few modifications: previtellogenic (no ongoing vitellogenesis with diameter &gt; 700 µm); stage A (vitellogenic oocytes with central germinal vesicle and no lipid-droplet coalescence); stage B (post-vitellogenic oocytes showing hyalinisation of the periphery of the cytoplasm); stage C (central germinal vesicle and early lipid-droplet coalescence); stage D (migration of the germinal vesicle and lipid-droplet coalescence) and hydrated eggs (fully hydrated eggs ready to be spawned). For statistical analysis, the earliest developmental stages (previtellogenic, A and B) and the latest ones (stages C, D and hydrated) were pooled in two groups named ‘stage 1’ and ‘stage 2’ respectively. Counts for each stages (stage1 and stage2) as well as the frequency of the stage 2 (freq_2) per female is reported.
- Proportions of fluent males (sperm) per condition from February to April of the first (1) and second (2) reproductive season.
- Number of eggs spawn per female (egg_female) and per day from February to April of the two reproductive seasons.”Day_of_spawning” indicates per each date if it was a spawning day (Y) or not (N) per each scenario;
- Total number of eggs spawn per female (total egg#/female) during the two reproductive seasons (relative fecundity).
- Physico-chemical parameters of the rearing water during the two reproductive seasons including the carbonate system components. For previous data concerning the physico-chemical water parameters of rearing tanks refer to (Cohen-Rengifo et al. 2022). Water pH (pH NIST) and temperature (t) were daily monitored by WTW 3110 pH meters (Xylem Analytics Germany, Weilheim, Germany; with electrode: WTW Sentix 41, NBS scale). The pH meters were daily calibrated with NBS certified WTW technical buffers at pH 4.01 and pH 7.00 (Xylem Analytics Germany, Weilheim, Germany). The total alkalinity (TA) of each tank was measured once a week following the protocol described previously (Cominassi et al. 2019) adapted from the protocol of Anderson and Robinson (1946) and Strickland and Parsons (1972). Seawater pH in total scale and pCO2 were calculated using the Microsoft Excel macro CO2sys (Lewis 1998) with the constants after Mehrbach et al. (Mehrbach et al. 1973), refit by Dickson et al. (Dickson and Millero 1987) (as cited in CO2sys). pCO2 and fCO2 values (µatm) were calculated from measured pH values in NSB scale, total alkalinity (µmol/kgSW), temperature (°C), oxygen content (%) and salinity (‰). Afterwards, total scale pH values were calculated with the same macro using pCO2 and fCO2 values.
References
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