The effect of physicochemical parameters and nutrients on the bioecology of Chondracanthus acicularis (Roth) Fredericq at three sites in the Moroccan Atlantic Ocean

The red algae Chondracanthus acicularis (Roth) Frederiq is a carrageenophyte commercialized in Morocco. A biological study was made on three sites on the Moroccan Atlantic coast with different fishing intensities (SidiRahal, El Jadida, and SouiriaKdima) to evaluate the impact of physicochemical parameters on the algae distribution. Biometric studies (weight and size) were carried out on different thallus in addition to stereomicroscopic observations to identify fertile thallus. Additionally, measurements of physicochemical parameters and nutrients were conducted each month in situ and in the laboratory. This study’s results showed that the highest biomass values were recorded in sampling sites characterized by optimal physicochemical and nutrient parameters, except for salinity. The highest biomass densities were recorded in April, February, and December at the Sidi Rahal site, El Jadida, and Souiria Kdima respectively. Minimum densities were recorded in December at the Sidi Rahal and El Jadida sites. While at SouiriaKdima, these minimum densities were recorded during October. The average thallus sizes were larger in Sidi Rahal relative to the other two sites. Minimum sizes were recorded during the winter period in the three studied sites. Conversely, maximum sizes were encountered in summer and early autumn.  The thalli of C. acicularis were fertile during the winter season in the three studied sites showing a negative correlation with temperature and salinity. In conclusion, this study shows that indeed physicochemical parameters have a slight effect on the bioecological parameters. Furthermore, knowledge of the fertility period will allow establishing a management plan to conserve the species.