Metabarcoding, direct stomach observation and stable isotope analysis reveal a highly diverse diet for the invasive green crab in Atlantic Patagonia

CORDONE G; THALINGER B; STEINKE D; VILACOBA E; LIJTMAER; LOZADA M; BIGATTI G; GALVÁN, DAVID E.

BIOLOGICAL INVASIONS

SPRINGER

Lugar: Berlin; Año: 2021 vol. 24 p. 505 - 526

1387-3547

TheEuropean green crab Carcinus maenas and its sister species C.aestuarii are highly invasive species causing damage to coastalecosystems and contributing to severe economic losses worldwide. C.maenas was first detected at the Atlantic Patagonian coast in 2001.In this work, we studied the diet of the green crab in a recentlyinvaded location in Golfo Nuevo, using three complementarytechniques: direct stomach observation, metabarcoding of gut contentand stable isotope analysis. Direct stomach observation andmetabarcoding showed that green crabs have a broad omnivorous diet,ingesting most of the phyla present in the study area. Gut contentmetabarcoding allowed a detailed description of algal diversity andrevealed other taxa that went unnoticed in the visual stomachanalysis. Stable isotope analysis showed that the major contributionto the crabs? diet was from the phytoplankton chain (by bivalveconsumption) and not directly from algae.This study approach combining three complementary techniques alsoallowed us to detect some differences in the diet between sexes,which suggests that male and female crabs are not as ecologicallyequivalent as previously thought. Besides, we detected sequencescorresponding to C. aestuarii suggesting that the green crabPatagonian population is a hybrid of both sister species. Thesefindings are key to understanding the impacts green crabs can have onthe local ecosystem.