Biometry of the red swamp crayfish <i>Procambarus clarkii</i> (Girard, 1852) in Ramsar sites in Morocco between 2016 and 2018

A population of red swamp crayfish Procambarus clarkii, (Girard, 1852) was studied in four wetland classified Ramsar sites in Morocco which are Merja Fouwarat, Merja Zerga, and Rmel plateau and Bas Loukous. The aim of this study was to collect the first information on the size and weight of Procambarus clarkii for the reasons of its invasion success in the wetlands Ramsar site in Morocco. Also, comparing the size and weight of the four crayfish populations can provide valuable information on the evolution of this species in the study area, and on the degree of adaptation and survival of this population in Morocco. A total of 10,007 specimens were collected from January 2016 to December 2018, and analysed for sex, weight and total length. The study was carried out monthly and for three periods per day in order to evaluate the breeding period and identify the peak movement period of this species. The maximum weight was noted at the low Loukous wetland in 2016 which is 18 g, in the same area the maximum size has been determined which is 17.5 cm. The Merja Fouwarat and Lower Loukous wetland shares the same minimum size, which is 6 cm. The minimum weight in our sample is 6.3 g was found in the Low Loukous Wetland in 2017. The results of this study showed also that these four wetlands show a favorable habitat for the development of the red crayfish population, and the differences between the total length TL), weight (W) and sex are statistically significant.