47 Medit. Mar. Sci., 21/1, 2020, 47-51 Mediterranean Marine Science Indexed in WoS (Web of Science, ISI Thomson) and SCOPUS The journal is available on line at http://www.medit-mar-sc.net DOI: http://dx.doi.org/10.12681/mms.20747 Research Article Unexpected massive enmeshments of the Sharpchin barracudina Paralepis coregonoides Risso, 1820 in mesopelagic sediment traps in the Levantine Basin, SE Mediterranean Sea Nir STERN 1 , Ronen ALKALAY 1,2 , Ayah LAZAR 1 , Timor KATZ 1 , Yishai WEINSTEIN 2 , Ilana BERMAN-FRANK 1 and Barak HERUT 1 1 Israel Oceanographic & Limnological Research, Haifa, 31080, Israel 2 Bar-Ilan University, Department of Geography, Ramat Gan, 52900, Israel Corresponding author: nirstern@ocean.org.il Handling Editor: Stelios SOMARAKIS Received: 1 June 2019; Accepted: 30 September 2019; Published online: 28 March 2020 Abstract This study reports exceptional penetrations of the Sharpchin Barracudina Paralepis coregonoides into pelagic, open-sea sedi- ment traps in the Levant Basin of the SE Mediterranean Sea. This first substantiated record of the species at the Levant Basin has been observed in two sediment traps at 180 and 280 m depth, 50 km offshore the coast of Israel. Over one year of deployment (November 2016 till November 2017), 483 adult individuals have been repeatedly entrapped inside the automatic sediment traps that were covered with a 25 mm baffler mesh for the first half year and then replaced with a smaller 10 mm mesh for the second half. This undesirable catch of such an elusive and understudied species enabled us to revise its distribution, abundance and ge- netic divergence. The continuous entrapment throughout the year of sexually mature individuals has confirmed that this species is common to the SE Mediterranean. In order to avoid unwanted entrapments that disrupt biogeochemical sediment studies, the installation of small mesh size nets on the conventional sediment trap openings must be considered in the pelagic zone of the SE Mediterranean, and probably elsewhere. Keywords: Paralepididae; Mesopelagic fishes; Mediterranean Sea; Genetic divergence; Mooring Station. Introduction The ocean mesopelagic zone covers the majority of earth’s volume and is characterized by a strong hydro- static pressure, diminished light and high inorganic nu- trient concentrations which makes it an appealing region for biogeochemical studies (Robinson et al., 2010; Sutton et al., 2017). Among the variety of methodologies that are being employed worldwide, the use of sediment traps greatly contributes to the documentation and understand- ing of the carbon pump and cycling within the mesope- lagic water column (Armstrong et al., 2002; Peterson et al., 2005; Trull et al., 2008). However, while sediment traps are considered as an ideal tool to gather biogeo- chemical data, the fluency of the process may be occa- sionally interrupted by various incidental forces. Mesopelagic fishes are highly abundant in oceanic waters with an estimated biomass of ten billion metric tons (St John et al., 2016), with many of them that per- form diel vertical migration (Gjøsaeter & Kawaguchi, 1980; Klevjer et al., 2012; Olivar et al., 2012), thus ac- tively transporting carbon throughout the water layers (Wang et al., 2019). Within this populated ecosystem, re- sides the fish family of barracudinas (Paralepididae) that contains almost 60 known circum-global species (Fricke et al., 2018). Barracudinas inhabit a wide gradient of the water column, from the surface down to 1,000 m, from the continental slope to mid-ocean areas (Harry, 1953), and in spite of their wide distribution and species rich- ness, the biology and distribution of this family remain largely understudied, with the last comprehensive study made by Harry (1953). The Mediterranean Sea contains six species of bar- racudinas, five of them are reported to inhabit the east- ernmost basin, the Levant Basin (Whitehead et al., 1984; Golani, 2005). In this study, we document a rare and prolonged an- nual accidental catch, between November 2016 to No- vember 2017, of 483 adult individuals of the rare Sharp- chin barracudina Paralepis coregonoides Risso, 1820, in two sediment traps at depths of 180 and 280 m, 50 km offshore the northern coast of Israel at the Levant Basin. Although this catch has impeded the original objectives of the biogeochemical study, it constituted the first con- firmed observation of the species in the eastern Mediter- ranean and granted a unique opportunity to obtain novel knowledge regarding the abundance and distribution of this elusive mesopelagic species.