Community structure of bathyal decapod crustaceans off South‐Eastern Sardinian deep‐waters (Central‐Western Mediterranean)

Abstract

Community structure and faunal composition of bathyal decapod crustaceans off South‐Eastern Sardinian deep‐waters (Central‐Western Mediterranean) were investigated. Samples were collected during 32 hauls between 793 and 1598 m in depth over the 2003–2007 period. A total of 1900 decapod specimens belonging to 23 species were collected. Multivariate analysis revealed the occurrence of three faunistic assemblages related to depth: (i) an upper slope community at depths of 793–1002 m; (ii) a middle slope community at depths of 1007–1212 m and (iii) a lower slope community at depths greater 1420 m. In the upper and middle slopes the benthic (Polycheles typhlops) and epibenthic–endobenthic feeders (mainly Aristeus antennatus and Geryon longipes), which eat infaunal prey, were dominant, followed by the macroplankton–epibenthic feeders such as Acanthephyra eximia and Plesionika acanthonotus. In the deepest stratum, the most remarkable feature was the prevalence of macroplankton–epibenthic feeders (A. eximia and P. acanthonotus). A small percentage of the benthic deep‐sea lobster Polycheles sculptus was also present. The biomass presented higher values in the middle slope and declined strongly in the lower slope. There was no general pattern of mean individual weight/size versus depth among decapods, and the changes seemed to be species‐specific with different trends.

Feeding Habits of Both Deep-Water Red Shrimps, Aristaeomorpha foliacea and Aristeus antennatus (Decapoda, Aristeidae) in the Ionian Sea (E. Mediterranean)

“…The feeding activity patterns of A. antennatus in the Greek Ionian Sea are, more or less, comparable to those reported in other geographical regions, such as the central (e.g. Relini & Orsi Relini, 1987;Follesa et al, 2009) or in the western Mediterranean (Cartes & Sardà, 1989;. Apparent differences in the activity patterns should be attributed to the more oligotrophic character of the Ionian Sea (E. Mediterranean) in relation to the western one and to the bottom morphology (Cartes, 1995).…”

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“…P. typhlops and S. robusta. A similar distribution of feeders in these depth zones have been identified in the central Mediteranean (Follesa et al, 2009) and off the SouthWest Balearic Islands (Western Mediterranean) (Maynou & Cartes, 2000). These differences could be attributed to the available food availability, the local geographic conditions which affect the species distribution and the vertical fluxes of organic carbon to the sea floor (Danovaro, Dinet, Duineveld, & Tselepides,1999).…”

“…The above mentioned relative consistent environmental conditions in the bathyal groups could explain the fact that does not change the abundance and biomass of decapods in the study area on small temporal scales (1 season). Although comparison of abundance with other studies is difficult, because of the different types of gear and methods used, the general decapod crustacean fauna distribution is quite similar to that found in other Mediterranean areas (Abelló et al, 1988;Cartes & Sardà, 1992;Cartes, Sorbe, & Sardà, 1994;Ungaro et al, 1999;Maynou & Cartes, 2000;Follesa et al, 2009). Other environmental parameter which affects the changes observed in the decapod assemblages on Le Danois Bank (Spain) is the nature of the substrate (Cartes et al, 2007).…”

“…Regarding their relative location in the water column, decapods crustaceans were classified as mesopelagic species (M), nektobenthic species (N) and benthic species (B) on the basis of their relative location in the water column (Cartes, 1998;Maynou & Cartes, 2000;Follesa et al, 2009).…”

Condition and recruitment of Aristeus antennatus at great depths (to 2,300 m) in the Mediterranean: Relationship with environmental factors

“…Most of the available information on A. antennatus biology (e.g., at the Balearic basin: Sardà & Demestre, ; Demestre, ; Sardà, Cartes, & Norbis, ; over Balearic slopes: Carbonell et al., , ; Cartes et al., ; Guijarro, Díaz, Massutí, & Moranta, ) was developed from commercial‐boat sampling, restricted to operating at depths of ca . 800–900 m. However, an important part of the population of this aristeid live as deep as 2,200 m in the western Mediterranean (Cartes & Demestre, ; D'Onghia et al., ; Follesa et al., ; Sardà & Cartes, ), with some isolated specimens collected to 3,300 m (Sardà et al., ). At these depths its ecology remains practically unknown.…”