Abstract
The structure of the cumacean assemblages from the southern margin of the Cap Ferret Canyon was studied at 13 stations ranging from 346 to 1099 m depth with a modified Macer-GIROQ suprabenthic sledge (four superimposed nets; 0.5 mm mesh size). A total of 1885 specimens were collected and classified into 5 families and 42 species. The total abundances fluctuated between 2.8 ind./100 m2 (station TS04; 484-485 m) and 55.8 ind./100 m2 (station TS08; 714-708 m). The highest values of species richness and diversity were recorded at station TS13 (1097-1099 m): S=25 species; H’(log2)=4.05. The near-bottom vertical distribution of the cumacean fauna showed the same pattern at all stations: at least 60% of the individuals were sampled by the lower net of the sledge and a drastic abundance decrease occurred between the two lowermost water layers sampled by the sledge. The multivariate analysis carried out on abundance data discriminated three main groups of stations distributed across depth (TS09 excluded): group Ia (346-485 m) characterized by the dominance of Nannastacidae (57.2%) at family level and Campylaspis sulcata, Leptostylis macrura at species level; group Ib (522-714 m) characterized by the dominance of Nannastacidae (66.1%) at family level and Campylaspis squamifera, C. laevigata and Leptostylis macrura at species level; and group II (790-1099 m) characterized by the dominance of Diastylidae (40.3%) at family level and Makrokylindrus (Adiastylis) josephinae, Leucon (Epileucon) pusillus and Diastyloides serratus at species level. According to this analysis, the main faunal change occurs between group I and II between 714 and 790 m, in relation to changes in the texture of surficial sediments. Although bathyal cumacean assemblages appear to be less abundant than those studied on continental shelves, they are significantly more diverse. However, such results could be in part related to the use of different sampling methods.
Highlights
Cumaceans are small peracarid crustaceans widely distributed from intertidal to hadal bottoms (Jones 1969) and showing the highest diversity in bathyal environments (Jones and Sanders 1972, Reyss 1973, Gage and Tyler 1992), a bathymetric distributional pattern recognized for most benthic taxa (Rex et al 1997, Rex and Etter 2010)
Summary: The structure of the cumacean assemblages from the southern margin of the Cap Ferret Canyon was studied at 13 stations ranging from 346 to 1099 m depth with a modified Macer-GIROQ suprabenthic sledge
The near-bottom vertical distribution of the cumacean fauna showed the same pattern at all stations: at least 60% of the individuals were sampled by the lower net of the sledge and a drastic abundance decrease occurred between the two lowermost water layers sampled by the sledge
Summary
Cumaceans (more than 1750 known species; see Watling and Gerken 2019) are small peracarid crustaceans widely distributed from intertidal to hadal bottoms (Jones 1969) and showing the highest diversity in bathyal environments (Jones and Sanders 1972, Reyss 1973, Gage and Tyler 1992), a bathymetric distributional pattern recognized for most benthic taxa (Rex et al 1997, Rex and Etter 2010) They represent one of the main faunal components of marine suprabenthic assemblages (Mees and Jones 1997) because they live close to the sediment-water interface, burrowing in the top layer substratum or swimming in the near-bottom water (see Foxon 1936, Forsman 1938, Dixon 1944). The present work is a new contribution to the knowledge of bathyal suprabenthic assemblages from the Cap Ferret area aimed at describing patterns of bathymetric as well as the near-bottom vertical distribution of cumacean species, estimating abundance of individuals and characterizing inter-specific associations
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.
