Effects of short-term hyposalinity stress on four commercially important bivalves: A proteomic perspective

Assessment of Risks Associated with Extreme Climate Events in Small-Scale Bivalve Fisheries: Conceptual Maps for Decision-Making Based on a Review of Recent Studies

“…As a consequence, two days after the stress event, the SFG recovered to normal values, except in spring. Gametogenesis is also negatively affected by low salinity [53] and there is some evidence suggesting that the change in reproduction affects the molecular stress response to very low salinity (around five) [55]. In winter, during sexual resting and the beginning of gametogenesis, a delay in this process was recorded, while at the peak of the reproductive period, low salinity levels triggered spawning, which may have resulted in a mismatch between the presence of larvae and phytoplankton, potentially causing starvation and diminishing the recruitment success [53].…”

“…Salinity variations were produced by mixing seawater and filtered freshwater and were monitored automatically by mini-CTDs (Star Oddi DST-CTD) placed in the tanks and manually by measurements made with a Hach HQ40D (for more details, see [50,52,75]). Bivalves (n = 30/species) were placed in boxes with sediment simulating low-tide conditions and were subjected to a gradual decrease in salinity (for more details, see [50,53,55,75]) over 6 consecutive days; the lowest salinity levels were reached during low tide and highest levels were reached during high tide, as occurs after heavy rainfall in the estuaries where the bivalve fishing beds are located. A similar set-up was used for the heatwave experiment conducted in July 2016, but with constant salinity and a simulated temperature increase (Figure 2B,C), with four different sediment temperatures reached during the diurnal, 4 h low-tide cycle (22, 27, 32 and 37 • C) during four days (for more details, see [51,53]).…”

“…The variables examined in both low salinity and heatwave experiments included various complementary aspects of the bivalve ecophysiology: mortality; scope for growth (SFG), i.e., the difference between energy acquisition (feeding and digestion) and energy expenditure (respiration, ammonium excretion and production of faeces), as defined by [76]; and behaviour (burrowing ability, valve closure) [50,51,75]. Additionally, tissue samples were taken from stressed and non-stressed individuals of each species for histological examination to determine the effects of these environmental stressors on reproduction [53] and production of mantle-edge proteins [55].…”

“…Eng. 2023, 11, x FOR PEER REVIEW 5 of 21 low-tide conditions and were subjected to a gradual decrease in salinity (for more details, see [50,53,55,75]) over 6 consecutive days; the lowest salinity levels were reached during low tide and highest levels were reached during high tide, as occurs after heavy rainfall in the estuaries where the bivalve fishing beds are located. A similar set-up was used for the heatwave experiment conducted in July 2016, but with constant salinity and a simulated temperature increase (Figure 2B,C), with four different sediment temperatures reached during the diurnal, 4 h low-tide cycle (22, 27, 32 and 37 °C) during four days (for more details, see [51,53]).…”

“…In addition, prolonged periods of valve closure result in accumulation of toxic metabolites, and the temporary cessation of filtration due to valve closure also implies reduced energy acquisition, with negative impacts on growth and physiological condition [44][45][46][47][48][49][50][51][52] and reproductive development [53]. Moreover, production of various molecules, such as heat-shock proteins and antioxidants protects cells from structural damage [54,55], although with a high associated energetic cost.…”