Abstract
Differences in the resource use patterns of males and females of the spider crab species Maja brachydactyla Balss, 1922 and M. squinado (Herbst, 1788) from several geographic areas (three in the Atlantic and two in the Mediterranean) were studied through the analysis of stable isotopes of carbon and nitrogen in the exoskeleton of post-pubertal (adult) specimens. Results confirmed that males and females from the same population usually did not differ in δ 15 N values and hence foraged at the same trophic level. In contrast, females were usually enriched in 13 C as compared with males from the same population, thus suggesting that females use shallower habitats than males before the terminal moult. The results reported here also indicate that stable isotop.
Highlights
The spider crabs of the genus Maja Lamarck, 1801 (Majoidea: Majidae), with around 20 described species worldwide, are represented on European coasts by four species: M. brachydactyla (Balss, 1922), M. crispata (Risso, 1827), M. goltziana (D’Oliveira, 1888) and M. squinado (Herbst, 1788) (Neumann 1998, Ng et al 2008, Sotelo et al 2008, 2009)
The results reported here indicate that stable isotopes can be useful for the traceability of commercial Maja species, but only if species and sex are incorporated in the analysis
Differences among populations were unrelated to species identity, as a Tukey post-hoc test revealed differences between the δ13C of M. brachydactyla from Ceuta and Galicia, but no differences between the δ13C of M. brachydactyla from Ceuta and that of M. squinado from Ancona or between the δ13C of M. squinado from Catalonia and the δ13C of M. brachydactyla from Galicia (Table 2)
Summary
The spider crabs of the genus Maja Lamarck, 1801 (Majoidea: Majidae), with around 20 described species worldwide, are represented on European coasts by four species: M. brachydactyla (Balss, 1922), M. crispata (Risso, 1827), M. goltziana (D’Oliveira, 1888) and M. squinado (Herbst, 1788) (Neumann 1998, Ng et al 2008, Sotelo et al 2008, 2009). M. brachydactyla and M. squinado are the largest European species of the genus and are found from subtidal areas to about 90 m depth (De Kergariou 1984, Števčić 1973). A diagnostic tool was developed to identify the four species of Maja in Europe with morphological and molecular methods (Guerao et al, 2011). Adults of M. brachydactyla and M. squinado are commercially exploited species and a simple relationship between carapace length (CL) and antorbital spine length could be used to differentiate the two species
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
