Abstract
The European green crab Carcinus maenas and its sister species C. aestuarii are highly invasive species causing damage to coastal ecosystems 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 recently invaded location in Golfo Nuevo, using three complementary techniques: direct stomach observation, metabarcoding of gut content and stable isotope analysis. 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 algal diversity and revealed other taxa that went unnoticed in the visual stomach analysis. Stable isotope analysis showed that the major contribution to the crabs’ diet was from the phytoplankton chain (by bivalve consumption) and not directly from algae. This study approach combining three complementary techniques also 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. These findings are key to understanding the impacts green crabs can have on the local ecosystem.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Declarations
Funding This research was supported by Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, Argentina) and Sistema Nacional de Datos Genómicos (SNDG, Argentina). Fieldwork campaigns and stable isotope analysis were funded by Fondo para la Investigación Científica y Tecnológica (FonCyT) under the grants PICT 2017-2403, PICT 2018-0903 and PICT 2018-0969. The metabarcoding analysis was funded by the Natural Sciences and Engineering Research Council of Canada and the Canada First Research Excellence Fund.
Conflicts of interest The authors declare that they have no conflict of interest.
Ethical approval All applicable institutional and/or national guidelines for the care and use of animals were followed. Permissions for sample collection were granted by the Secretaría de Pesca and Secretaría de Conservación de Áreas Protegidas, Chubut Province. Export permits were granted in 2019 by the Dirección Nacional de Biodiversidad (Secretaría de Ambiente y Desarrollo Sustentable) under ANEXO II, resolution number: IF-2019-40388897-APN-DNBI#SGP.
Consent to participate Not applicable
Consent for publication Not applicable
Availability of data and material All data generated and analysed for this study are included in Electronic Supplementary Material: Online Resource 1, 2, 3, 4, and 5 (ESM 1, ESM 2, ESM 3, ESM 4, ESM 5, and ESM 6). The raw sequence data was uploaded to Genbank SRA (accession: SRR13517441).
Code availability The code was implemented in R and it is available upon request (R Core Team, 2020).
The new versionis the accepted version in the journal Biological Invasions. The final version includes revised supplementary material.
