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This work is the first study on biology and biochemistry of Libinia dubia on the Mediterranean Sea as well as socio-economic impacts of this spider crab proliferation on artisanal fishing activities along the Tunisian coasts. Morphometric characteristics of 913 spider crabs collected in 2016 within the Gulf of Gabes in Tunisia were examined. A sexual dimorphism was observed concerning the body, chelar propodus and abdomen form and sizes. Crab's carapace width ranged from 22.7 to 89.1mm and from 4.02 to 74.5mm, for males and females, respectively. The sex ratio was male biased (M: F=1: 0.92). Local Ecological Knowledge surveys revealed a decline in fishermen's income of 72% due to crab invasion (damages of fishing nets and catches, decrease of working days and catch yield). Socio-economic impacts of Libinia dubia can be reverted into profits by using crab exoskeleton (shells) for feeding and for bioactive molecules extraction. They are mainly composed of ash (71% of the dry weight dw), chitin (from 14.66% to 15.13% dw), crude proteins (11%) and fats (between 0.49% and 0.86%) with no sex difference for all studied parameters (p>0.05). Exoskeletons are largely composed of calcium, magnesium and phosphorus with heavy metals contents (Pb and Cd) under the detection limits (0.04ppm).