A critical habitat for Mediterranean fish resources: Shelf-break areas with Leptometra phalangium (Echinodermata: Crinoidea)

• Published in: Marine Biology
• Main Authors: COLLOCA, FRANCESCO, ARDIZZONE, Domenico, Paolo Carpentieri, E. Balestri
• Other Authors: Colloca, Francesco, Paolo, Carpentieri, E., Balestri, Ardizzone, Domenico
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2004
• Subjects: cod gadus morhua; population structure; continental slope; hake merluccius merlucciu; lophelia pertusa; demersal assemblage; temporal distribution; european hake; community structure; central tyrrhenian sea; Argentina; Hake; Gadus morhua; Lophelia pertusa
• Online Access: http://hdl.handle.net/11573/362324; https://doi.org/10.1007/s00227-004-1405-8; http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=000224888100007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=0c7ff228ccbaaa74236f48834a34396a; http://www.scopus.com/inward/record.url?eid=2-s2.0-11144274523&partnerID=65&md5=714672717f2f768e238533fd42e6eb6a

This paper considers the potential role of the crinoid Leptometra phalangium as an indicator of highly productive areas along the shelf break that can sustain large biomasses of benthopelagic fish and recruits. The structure of fish assemblages in the central Mediterranean Sea (central-western coast of Italy), analysed on the basis of surveys carried out in summer and autumn from 1997 to 2001, revealed the presence of a well-defined group of species on the shelf break. This area, occurring at a depth of between 120 and 170 m, is characterised by detritic organogenic sediments colonised by the crinoid L. phalangium, a suspension-feeding macro-epibenthic species confined in the Mediterranean to the shelf-break area. Its abundance in the studied area can reach 12 - 15 ind. m(-2). A total of 121 species belonging to 66 families of demersal organisms ( crustacean decapods and stomatopods, cephalopods, selaceens and teleosteens) were caught at shelf-break stations from September to October. The species which typified the assemblage were the fishes Trisopterus minutus capelanus, Merluccius merluccius, Glossanodon leioglossus, Argentina sphyraena, Capros aper, Macroramphos scolopax and Lepidotrigla cavillone, the crustacean decapod Parapenaeus longirostris and the cephalopods Illex coindetii and Todaropsis eblanae. Detritic shelf-break stations showed a higher abundance of demersal organisms than stations distributed on muddy bottoms in the same depth range ( 100 - 200 m). Such differences appeared to be significant in September - October, when a clear increase in benthopelagic zooplanktivorus species, such as Glossanodon leioglossus, Trachurus trachurus, Trachurus picturatus, was found. The length structure of species occurring on the shelf break showed that for some of them the selection of this area is related to specific phases of their life cycle. Significant highest abundance of recruits and juveniles was observed for Merluccius merluccius, Helicolenus dactylopterus, Phycis blennoides, Parapenaeus longirostris and ...