Impact of climate change on coastal versus estuarine nursery areas: cellular and whole-animal indicators in juvenile seabass Dicentrarchus labrax

Abstract

The effects of thermal conditions of coastal and estuarine nurseries, both in the present and in the near future, on juvenile fish were compared. The response of the European seabass Dicentrarchus labrax was investigated through a long-term experiment in captivity, where 0-group juveniles were exposed to temperatures that reflect the average summer temperature that they encounter in coastal (18°C) and estuarine nurseries (24°C), and also the temperature that they endure inside estuaries during heat waves (28°C). The combined expression of 2 heat shock proteins (Hsc/Hsp70) in white muscle was assessed throughout a long-term experiment (30 d). Growth and condition were determined at the end of the experiment. Hsc/Hsp70 levels were constant throughout the first 15 d at 18°C, and then decreased steeply. At 24 and 28°C, Hsc/Hsp70 levels increased considerably after 15 d, particularly at 28°C, and decreased at the end of the experiment. Daily growth was 0.20 mm d −1 at 18°C, it increased to 0.34 mm d −1 at 24°C, and was lowest at 28°C, at 0.16 mm d −1 . Condition, assessed by Fulton's K, was 0.95 at 18°C, 1.00 at 24°C and 0.83 at 28°C. The Hsc/Hsp70 increase at 24 and 28°C is an indication that molecular reparation processes were underway. The peak growth and condition values registered at 24°C suggest that estuarine average summer temperatures are more bene ficial for this species' juveniles than coastal temperatures. Acclimation was observed at 24°C, yet growth rates and condition values indicate that prolonged heat waves (28°C) may result in lower fitness.

Thermal sensitivity of native and invasive seabreams

“…These experimental temperatures had previously been used with other temperate and subtropical fishes with minimal effects on survival (Vinagre et al . ,b,c). Based on their distribution ranges and the habitats where they live, our initial expectation was that seabreams would be among the more heat‐resistant species at temperate latitudes.…”

Effects of Temperature in Juvenile Seabass (Dicentrarchus labrax L.) Biomarker Responses and Behaviour: Implications for Environmental Monitoring

“…Induced oxidative stress is also described as responsible for an increase in cholinesterase activity in neuronal models (Melo et al 2003), and an increase in synaptic neurotransmission caused by increased cell membrane fluidity is also related with swimming disturbances in goldfish (C. auratus) exposed to heat stress (Szabo et al 2008). Recent findings indicate an increase in the combined expression of two heat shock proteins (Hsc/Hsp 70) in muscle of juvenile seabass exposed to 24 and 28°C (Vinagre et al 2012b), pointing out that molecular processes of reparation are occurring at these temperatures and also corroborating the hypothesis of induced thermal stress responses at 24°C or higher in seabass juveniles.…”

“…It is also an economical important species being used for human consumption, and that may be adversely affected by temperature increase (Cabral and Costa 2001;Vinagre et al 2009), particularly considering the areas that are in the southern range of their distribution and in the upper limit of their thermal tolerance. Given its pertinence, this species has been selected in recent studies focusing on this subject, including on thermal tolerance definition (Madeira et al 2012), and on the effects of climate change and heat waves on mortality, growth, condition (Vinagre et al 2012c), oxidative stress parameters (Vinagre et al 2012a) and heat shock protein expression (Vinagre et al 2012b). However, at the best of our knowledge, the physiological parameters selected for the present study were not previously tested in D. labrax exposed to different temperatures, except two of the antioxidant parameters, LPO levels and CAT activity (Vinagre et al 2012a).…”

Cross-effects of dietary probiotic supplementation and rearing temperature on antioxidant responses in European seabass [Dicentrarchus labrax(Linnaeus, 1758)] juveniles

“…(), as lipid peroxidation increased when seabass were maintained outside the optimal temperature interval. Thermal stress was suggested as a possible cause, further confirmed by the high variation of specific cellular expressions such as heat stress proteins (HSP70; Vinagre, Madeira, Narciso, Cabral, & Diniz, ). Another low‐temperature adaptation of seabass was reported by Trigari et al.…”

“…Similar results were described by Vinagre et al (2012a), as lipid peroxidation increased when seabass were maintained outside the optimal temperature interval. Thermal stress was suggested as a possible cause, further confirmed by the high variation of specific cellular expressions such as heat stress proteins (HSP70; Vinagre, Madeira, Narciso, Cabral, & Diniz, 2012b). Another low-temperature adaptation of seabass was reported by Trigari et al (1992), where they showed a lipid metabolism modulation, triggered by changes in the deposition of fatty acids, particularly in liver cell membranes.…”