## 3 Results and Discussion

Table 9: Results of pairwise tests examining the significant factor of ‘Zones’ obtained in the two-way PERMANOVA analyzing the variation in the content of heavy metals and trace elements in liver tissue in species according to study zone, considering the level of the factor “Zones”. Table 10 shows the comparison with other authors; it should be noted that not many studies have analyzed the concentration of metals and trace elements in _S. cretense_ and _S. atricauda_ in the Atlantic Ocean. In fact, after reviewing the literature, the only data found for _S. cretense_ in the Canary Islands [36; 37] show that the concentrations reported more than 25 years ago in _S. cretense_ are much higher than those obtained in the present study. In the case of toxic heavy metals such as Cd (0.077 mg/kg) and Pb (1.43 mg/kg), the concentrations are more than ten times higher than the data obtained in the present study. This may be explained by the fact that current environmental regulations and controls are stricter than those that were in force in the past, and, perhaps more importantly, because gasoline is no longer made with Pb. The study of [PERSON] et al. [15] on the island of Gran Canaria (Canary Islands) reports that the metal concentrations in _S. cretense_, with the exception of Pb (0.23 mg/kg), were lower than those obtained in the present study. [PERSON], 2017 analyzed the trace elements in _Serranus cabrilla_ from Tenerife (Canary Islands) and found higher concentrations of Al, Ba, Cd, Cu, Fe, Li, Ni and Pb. These values suggest that _S. cabrilla_ bioaccumulates more metals than _S. atricauda_. [PERSON] et al. [38] studied the concentrations of _Serranus scriba_ on the coast of Mauritania, identifying levels of 20 mg/kg of Zn, which is five times higher than the concentrations obtained in the present study, and this may be due to the fact that Mauritania is influenced to a greater degree than the Canary Islands by the Sahara Desert, which is rich in Zn, as the upwelling it creates brings nutrients to the surface waters [14; 39; 40; 41]. Studies carried out in the Mediterranean Sea, in Egypt and in Turkey report values in all metals and trace elements greater than those in the present study, and this is because the Mediterranean Sea is a closed sea whose only opening to the Atlantic is the Strait of Gibraltar and, therefore, it has a notably low water renewal rate, causing pollutants to accumulate in organisms [42; 43; 44; 45]. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Atlantic Ocean**} & \multicolumn{4}{c}{**Mediterranean Sea**} \\ \hline  & \multicolumn{4}{c}{**Canary Islands**} & \multicolumn{4}{c}{**Mauritania**} & **Egypt** & **Turkey** \\ \hline  & _Serranus_ & _Sparisoma cretense_ & _Serranus_ & _Serranus_ & _S._ & _Serranus_ & _S._ & _S._ \\  & _atricauda_ & & _Sparisoma cretense_ & _cabrilla_ & _scriba_ & _cretense_ & _cabrilla_ & _cretense_ & _cabrilla_ \\ \hline
**Al** & 1.354 & 1.407 & 2.37 & 4.438 & & & 16.8 & \\ \hline
**B** & 0.245 & 0.106 & 0.16 & 0.138 & & & & \\ \hline
**Ba** & 0.128 & 0.254 & 0.084 & & 0.456 & & & \\ \hline
**Ca** & 3561 & 2591 & 105.21 & & 562.1 & & & 2762 \\ \hline
**Cd** & 0.007 & 0.006 & 0.001 & 0.77 & 0.107 & 0.02 & 0.6 & & \\ \hline
**Cr** & 0.091 & 0.117 & 0.13 & & 0.010 & & & \\ \hline
**Cu** & 0.559 & 0.479 & 0.37 & 1.6 & 1.7 & 0.735 & 0.3 & 0.4 & 8.3 & \\ \hline
**Fe** & 2.992 & 2.552 & 2.21 & 9.41 & 9.3 & 7.026 & & & \\ \hline
**K** & 2275 & 2381 & 2054 & & 2475 & & & 17,865 \\ \hline
**Li** & 0.241 & 0.241 & 0.42 & & 1.201 & & & \\ \hline
**Mg** & 352.9 & 333.4 & 281.8 & & 282.1 & & & 1331 \\ \hline
**Mn** & 22.78 & 23.66 & 0.09 & & 0.172 & & & \\ \hline
**Mo** & 0.014 & 0.014 & 0.003 & & 0.013 & & & \\ \hline
**Na** & 862 & 831 & 488.1 & & 909.3 & & 3723 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Comparison with other authors (mg/kg).