Pb, Cd, and Cu concentrations in Scyliorhinus canicula (Linnaeus, 1758) and M. merluccius (Linnaeus, 1758):...

The accumulation of heavy metals in marine organisms is an increasing concern due to their potential impacts on ecosystem health and food safety. Scyliorhinus canicula has been proposed as a potential biomonitor owing to its benthic habits, high abundance, and philopatric behaviour, which may make it suitable for tracking metal contamination in commercial fish species. This study compares the concentrations of lead (Pb), cadmium (Cd), and copper (Cu) in the muscle tissues of two demersal species, S. canicula and Merluccius merluccius, collected from the western Mediterranean. Samples (n = 45 per species) were obtained from commercial bottom trawl fisheries and analyzed using graphite furnace atomic absorption spectrometry (GFAAS). The results revealed significant interspecific differences in Cu and Cd concentrations (p < 0.001), with S. canicula exhibiting higher mean values (Cu: 0.383 ± 0.099; Cd: 0.011 ± 0.003 mg·kg^-1 ww) compared to M. merluccius (Cu: 0.188 ± 0.060; Cd: 0.005 ± 0.003 mg·kg^-1 ww). Although Pb concentrations were generally higher in M. merluccius (0.050 ± 0.017 mg·kg^-1 ww) than in S. canicula (0.036 ± 0.015 mg·kg^-1 ww), this difference was not statistically significant (p > 0.05). Strong positive correlations in Pb (r = 0.833, p = 0.004) and Cd (r = 0.817, p = 0.005), and a moderate correlation in Cu (r = 0.633, p = 0.038), suggest that both species are exposed to similar contamination sources. Variability in metal accumulation may be influenced by differences in diet, physiology, and species-specific metabolic pathways. Given the strength of these interspecific correlations, S. canicula shows strong potential as a biomonitor for assessing heavy metal contamination in M. merluccius, and potentially in other commercially important fish species-thereby contributing to more effective marine pollution monitoring strategies.