Publication Date:
2018-08-24
Description:
The invasive Asian shore crab Hemigrapsus sanguineus and the native European
green crab Carcinus maenas share intertidal habitats along European North Atlantic shores and
may compete for food. We evaluated the energy-storing capacities of the 2 species and determined
their dietary preferences by means of lipid analysis and fatty acid trophic marker indices.
Specimens of both sexes and various sizes were sampled in the rocky intertidal of the island of
Helgoland (North Sea) in April, June, August, and October 2015. Total lipids of the midgut glands
were significantly higher in H. sanguineus than in C. maenas and followed a distinct seasonal
cycle in both sexes (ca. 20−50% of dry mass, DM). The lower lipid contents of C. maenas (ca. 20%
of DM) remained at a similar level throughout the seasons. The seasonal differences in the females
of H. sanguineus may be due to higher reproductive output and, consequently, lipid turnover, but
remain unexplained in males. Trophic indices for Bacillariophyceae, Chlorophyta, and especially
Phaeophyceae were higher in H. sanguineus than in C. maenas, suggesting a higher degree of
herbivory of the invader. In contrast, the Rhodophyta index was higher in C. maenas. Thus, competition
for food between the 2 species will probably be low in habitats rich in macroalgae. The
ability of H. sanguineus to utilize mainly energy-poor algae but accumulate high-energy reserves
may be an advantage for successfully establishing persistent populations in new habitats.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
