AbstractThe European green crab Carcinus maenas and, its sister species, C. aestuarii are highly invasive species causing damages to coastal ecosystems and severe economic losses worldwide. C. maenas was detected at the Atlantic Patagonian coast twenty years ago. In this work, we studied the diet of the green crab in a recently invaded location in Nuevo Gulf, using three complementary techniques: direct stomach observation, stable isotope analysis, and metabarcoding of the gut content. Direct stomach observation and metabarcoding showed that green crabs have a broad omnivorous diet, ingesting most of the phyla present in the study area. Gut content metabarcoding allowed a detailed description of algae diversity and revealed other taxa that went unnoticed in the visual stomach analysis. Stable isotope analysis showed that the major contribution to crabs’ diet was from the phytoplankton chain (by bivalve consumption) and not directly from algae. This study approach combining three complementary techniques allowed us to detect some differences in the diet between sexes, which suggests that male and female crabs are not as ecologically equivalent as previously thought. Besides, we detected sequences corresponding to C. aestuarii suggesting that the green crab Patagonian population is a hybrid of both sister species. Finally, we highlight possible direct and indirect interactions of the green crab with the native species that can trigger negative effects throughout the entire food web.
Metabarcoding, direct stomach observation and stable isotope analysis reveal a highly diverse diet for the invasive green crab in Atlantic Patagonia
