Swimbladder properties of Cyclothone spp. in the northeast Atlantic Ocean and the Western Mediterranean Sea

• Published in: Frontiers in Marine Science
• Main Authors: Sarmiento Lezcano, Airam N., Olivar, M. Pilar, Caballero, M. José, Couret, Maria, Hernández León, Santiago, Castellón, Arturo, Peña, Marian
• Other Authors: Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media 2023
• Subjects: Micronekton; Bristlemouth; Swimbladder; Gas; Fatty-tissue; Histology; Body-mass density; Conserve and sustainably use the oceans; seas and marine resources for sustainable development; Sarmiento; North Atlantic; Northeast Atlantic
• Online Access: http://hdl.handle.net/10261/327875; https://doi.org/10.3389/fmars.2023.1093982

22 pages, 11 figures, 7 tables.-- Data availability statement: Publicly available datasets were analyzed in this study. This data can be found here: Olivar et al. (2022) https://doi.org/10.1594/PANGAEA.947631 and Sarmiento-Lezcano et al. (2023) https://doi.org/10.1594/PANGAEA.95494 Non-migratory bristlemouth fishes (Cyclothone spp.) are the most abundant vertebrates on Earth and play an important role in the biological carbon pump by remineralizing organic carbon in deep ecosystems. Acoustic data and net sampling are often used in combination to estimate fish and zooplankton biomass, but this procedure may be subject to several sources of error when applied to mesopelagic species. For instance, the allocation of echoes to species has often been biased by not considering Cyclothone spp. due to the use of nets targeting larger fish. Furthermore, the acoustic properties of the target organisms must be well understood to convert acoustic density into numerical density. The characteristics of a fish’s swimbladder are the most relevant features necessary to assess its acoustic properties. This study provides information on the swimbladder properties of six Cyclothone species inhabiting the meso- and bathypelagic layers in the North Atlantic Ocean and Mediterranean Sea, including swimbladder location within the body, fat tissue content, morphology, morphometry (only available for C. braueri and C. pseudopallida), and fish body-mass density (only available for C. braueri, C. pseudopallida, C. pallida, and C. pygmaea). The studied species showed a functional physoclistous swimbladder, with well-developed gas glands and rete mirabile and numerous capillaries in the case of the shallower species C. braueri and C. pseudopallida (mainly distributed from 400 to 600 m depth), and a fat-invested swimbladder in species with deeper vertical distribution (C. livida, C. microdon, C. pallida, and C. pygmaea). The fat content in the swimbladder (C. pallida and C. microdon) increased with depth and latitude, reducing the space in ...