Seasonal abundance and trophic position of the Atlantic blue crab Callinectes sapidus Rathbun 1896 in a Mediterranean coastal habitat

Abstract

The blue crab Callinectes sapidus, native to the western coasts of the Atlantic Ocean, has been introduced in Mediterranean waters where it is currently considered an invasive species. Here, we verified the occurrence of an established population of C. sapidus in the Torre Colimena basin, a Mediterranean habitat located in SE Italy, and provided a first assessment of its functional role in a Mediterranean coastal ecosystem. Crab traps were used to estimate the species abundance at a seasonal frequency; in addition, its trophic position was estimated in summer using nitrogen stable isotopes. Estimations were performed using both a generally adopted value of 3.4 % for the nitrogen trophic level fractionation factor D15N, and species-specific\ud estimations obtained from the literature. C. sapidus was sampled throughout the year, reaching peak abundances in summer. This result, taken together with the observed patterns of variation in the average body size and sex ratio of captured specimens, provided evidence of a fully established population in the Torre Colimena basin. The estimated trophic position of the crab was consistent with the literature information on western Atlantic populations,\ud and resulted, irrespective of the fractionation factor used, significantly provided novel information on the occurrence and potential functional impact of this non-indigenous species in Mediterranean coastal habitats, highlighting current knowledge lacunae and identifying future research lines on marine\ud alien species. than those characterizing an autochthonous brachyuran (Pachygrapsus marmoratus) and a fish predator (Sparus aurata). The present study provided novel information on the occurrence and potential functional impact of this non-indigenous species in Mediterranean coastal habitats, highlighting current knowledge lacunae and identifying future research lines on marine alien species

The trophic position of the Atlantic blue crab Callinectes sapidus Rathbun 1896 in the food web of Parila Lagoon (South Eastern Adriatic, Croatia): a first assessment using stable isotopes.

“…The TP estimation is consistent with that of other investigations performed using stable isotopes, ranging from 2.8 to 4.3 (Moncreiff & Sullivan, 2001;Abreu et al, 2006;Rooker et al, 2006;Rodriguez-Graña et al, 2008;Winemiller et al, 2007;Carrozzo et al, 2014). Most importantly, this study indicated that a considerable size-related variation occurs in the trophic position of C. sapidus, increasing from values as low as 3.34 for juveniles to values in the 3.7 -4.11 range for the largest individuals.…”

“…The marbled crab P. marmoratus, specifically, is an opportunistic omnivore, including, as for the blue crab, both plant and animal prey in its diet (Cannicci et al, 2002;Chartosia et al, 2010). It is worth noting that previous estimations of the trophic position using stable isotopes indicated for the marbled crab a TP value of 2.12 (Carrozzo et al, 2014), fully consistent with a trophic habit including mainly macrophytes. Conversely, in the present study the estimated TP was 2.96 (Table 2), identifying P. marmoratus as a predator.…”

“…Traps of the type described in Carrozzo et al (2014) were used to collect crab specimens. Each trap (60×60×60cm) was made of vinyl-coated 2×2 cm mesh wire with an upper and lower chamber ("kitchen" and "parlour" chamber, respectively;Sturdivant and Clark, 2011).…”

“…Sci., 17/3, 2016, 634-643 635 The functional importance of the blue crab in coastal ecosystems of NW Atlantic and other native habitats has been repeatedly assessed (e.g. Baird & Ulanowicz, 1989;Dittel et al, 2000Dittel et al, , 2006Hines, 2007); conversely, to date an assessment of the trophic position and potential ecological impact of the species on benthic food webs has been performed only in two coastal basins in SE Italy (Mancinelli et al, 2013a;Carrozzo et al, 2014). In this study, we analysed the trophic position of C. sapidus in the Parila Lagoon, a coastal basin located in the estuary of the Neretva River (Croatia).…”

Parasites affect hemocyte functionality in the hemolymph of the invasive Atlantic blue crab Callinectes sapidus from a coastal habitat of the Salento Peninsula (SE Italy)

“…The Atlantic blue crab Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) is native to the north-western Atlantic Ocean coasts; the first record from European waters was in 1901 along the Atlantic coasts of France (Nehring, 2011); subsequently, it extended its presence throughout the Mediterranean Sea (Mancinelli et al, 2017a). In particular, the blue crab has been recorded in the Adriatic (Dulčić et al, 2011;Mancinelli et al, 2016;Cilenti et al, 2015) and Ionian Seas (Mancinelli et al, 2013a(Mancinelli et al, , 2017bCarrozzo et al, 2014), where a number of established, fully reproductive populations have been identified. Currently, C. sapidus is considered an invasive alien species (IAS) in the Mediterranean Sea (Katsanevakis et al, 2014).…”