## 1 Introduction  
In the western Mediterranean Sea, the wedge clam (_Donax trunculus_) and the striped venus clam (_Chamelea gallina_), among other species, hold significant socio-economic value as fishing resources and consequently face high fishing pressure [1, 2]. These filter-feeding bivalve mollusks inhabit fine sandy bottoms [3, 4]. \(D\). _trunculus_ exclusively resides in the biocenosis of superficial fine sands [5] with strong dependence on the nature and composition of the sediment [6]. On the other hand, the striped venus clam is preferentially distributed in the coastal biocenosis of well-selected fine sand [7], typically found at depths of 3 to 12 m [8], while wedge clams are predominantly distributed between 0 and 2 m deep [9]. Over the recent few decades, the fisheries of these clam species have witnessed a significant decline in the Spanish Mediterranean Region [1, 2, 10]. This decline has led to the gradual closure of fishing grounds by local authorities or the abandonment of fishing activities in some regions [1]. Management measures, such as legal minimum size requirementsor spatial-temporal closures to avoid the fishing during the spawning season, have been implemented to address this situation [2; 11]. Despite these efforts, the populations of wedge clams and striped venus clams have not recovered [1], resulting in severe consequences, including the loss of employment for hundreds of small-scale fishermen [1]. Marine ecosystems, particularly in the Mediterranean Sea, are experiencing the impacts of global climate change [12], chemical pollution [13], and biological pollution [14], resulting in significant effects on marine biodiversity [15; 16]. While the ocean absorbs both CO\({}_{2}\) and heat, slowing atmospheric warming, it also undergoes changes such as increased water temperature, reduced pH, decreased dissolved oxygen, salinity fluctuations, heatwaves, rising sea levels, and alterations in ocean currents [17]. Each of these stressors has its own effect, acting both independently [18] and synergistically [19; 20]. Warming, acidification, deoxygenation, and salinity changes occur more rapidly in shallow water habitats, influenced by continental factors. Other anthropogenic pressures such as high urban pressure, mass tourism, overfishing, increased maritime traffic, sewage disposal, and extensive use of fertilizers are added to these coastal marine zones [21]. Consequently, the Mediterranean Sea is being pushed into a new and, at least, uncertain state by all these stress sources [14]. [PERSON] et al. [22] linked changes in the temperature of surface waters of the Mediterranean Sea to mass mortality events of invertebrates, including mollusks, concluding that the frequency of mass mortality of benthic invertebrates is increasing and correlates with positive thermal anomalies. In the Mediterranean, marine heat waves are not only more frequent but also more intense and of longer duration [23]. Therefore, the two species under study may struggle to maintain good health at high temperatures. [PERSON] and [PERSON] [24] demonstrated that _C. gallina_ at temperatures of 28 \({}^{\circ}\)C increased their respiration rate, potentially leading to metabolic imbalances, while [PERSON] and [PERSON] [25] suggested that wild clams may experience high stress levels at such temperatures potentially causing death [26]. In the case of _D. trunculus_, [PERSON] et al. [27] observed a high thermal tolerance for this species, reflecting its distribution in shallower waters; however, their determinations were carried out working with short exposure periods of up to 96 h.  
Marine bivalves are osmconformers capable of maintaining metabolic function despite changes in osmolarity and cytosol composition during changes in salinity [28]. Closing and sealing of the valves are vital responses to stressful salinity [29]. Despite these adaptations, salinity variations can also cause mortality of benthic bivalves [30]. Although _D.