BioProject

Salinity is a major factor that can affect greatly the viability of the fish larvae during their developing stages. More...

Salinity is a major factor that can affect greatly the viability of the fish larvae during their developing stages. Natural populations are exposed to high fluctuation in the environmental conditions. Also, salinity management is of high relevance in hatcheries. The objective of this study was to determine the biological effects of environmental salinities on larval development in sole. Larvae were exposed to two salinities, 10 and 36 ppt, from eggs until the 3 days after hatching. Expression profiles were determined using RNA-seq, microarray and validated using qPCR. Important malformations were identified. The identification of key molecular pathways affected by salinity can help to understand the effects of salinity during early developmental stages with a profound impact to evaluate the effects of climate change and improve hatchery practices. Overall design: Fertilized eggs of Senegalese sole were collected from spontaneous spawn at “El Toruño” facilities (El Puerto de Santa María, Cadiz). Temperature in the broodstock during the spawning was approximately 18.5ºC and salinity 34 ppt. Eggs were transferred to a 1,000-mL measuring cylinder to separate buoyant (viable) from non-buoyant (non-viable) eggs and the number in each fraction was estimated using volumetric methods (1,100 eggs mL-1). After estimating the number of fertilized eggs, we incubated embryos (at the gastrula stage) in 15-L cylinder tanks at an initial density of 2,000 embryos L-1. After seeding, two salinities (10 and 36 ppt) were established using a recirculation system that kept constant temperature (20ºC±0.5) and target salinity. Water turnover was maintained at one total renewal per hour during the experiment. Trial was done in duplicate tanks for each salinity. After hatching, larvae were sampled at day 3 using a 350 µm-mesh net. Three pools of larvae were collected from each tube (~100 larvae/pool), washed with DEPC water, frozen directly in liquid nitrogen and stored at -80 °C until analysis. Less...