17
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Swimbladder function and the spawning migration of the European eel Anguilla anguilla

      review-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          The spawning migration of the European eel is an extensive journey over 5000 to 7000 km from the European coast to the Sargasso Sea. Eels do not feed during this journey and on-board fuels must be sufficient to support the journey of 3.5 to 6 month, as well as sexual maturation and the spawning activity. Swimming of eels appears to be quite energy efficient compared to other fish species, and elevated hydrostatic pressure has been shown to even reduce the costs of transport. Recent studies revealed, however, that during traveling eels perform extensive diurnal migrations and swim at a depth of about 100–300 m at night time, but go down to 600–1000 m at day time. At a depth of 200 m eels are exposed to a hydrostatic pressure of 21 atmospheres (2.13 MPa), while at 800 m hydrostatic pressure increases to 81 atmospheres (8.21 MPa). Accordingly, without any compensation at a depth of 800 m swimbladder volume will be reduced to about 25% of the volume established with neutral buoyancy at 200 m. Consequently, these diurnal changes in depth must be taken into consideration for a calculation of the energy requirements of the spawning migration. Without compensation a compression of the swimbladder will result in a status of negative buoyancy, which makes swimming more costly. Trying to keep the status of neutral buoyancy during descent by gas secretion into the swimbladder in turn requires metabolic activity to enhance swimbladder perfusion and for acid production of the gas gland cells to stimulate gas secretion. During ascent gas is passively removed from the swimbladder in the resorbing section and in the blood transported to the gills, where it is lost into the water. Accordingly, the swimbladder appears to be a crucial organ for the spawning migration. It can be assumed that an impairment of swimbladder function for example due to an infection with the nematode Anguillicola crassus significantly threatens the success of the spawning migration.

          Related collections

          Most cited references65

          • Record: found
          • Abstract: found
          • Article: found
          Is Open Access

          Reactive Oxygen Species in Health and Disease

          During the past decades, it became obvious that reactive oxygen species (ROS) exert a multitude of biological effects covering a wide spectrum that ranges from physiological regulatory functions to damaging alterations participating in the pathogenesis of increasing number of diseases. This review summarizes the key roles played by the ROS in both health and disease. ROS are metabolic products arising from various cells; two cellular organelles are intimately involved in their production and metabolism, namely, the endoplasmic reticulum and the mitochondria. Updates on research that tremendously aided in confirming the fundamental roles of both organelles in redox regulation will be discussed as well. Although not comprehensive, this review will provide brief perspective on some of the current research conducted in this area for better understanding of the ROS actions in various conditions of health and disease.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            A review of the possible impacts of long-term oceanic and climate changes and fishing mortality on recruitment of anguillid eels of the Northern Hemisphere.

            Possible causes of declines in recruitment of European, American and Japanese eels to continental waters are reviewed. Negative correlations between the Den Oever glass eel recruitment index (DOI) and the North Atlantic Oscillation Index since 1938 are discussed, together with older anecdotal evidence. Correlations are established between the DOI and sea surface temperature anomalies at 100-250 m between 1952 and 1995 in the Sargasso Sea/Sub-Tropical Gyre (STG) spawning area. It is hypothesised that, associated with global warming trends, STG warming inhibits spring thermocline mixing and nutrient circulation, with negative impacts on productivity and hence food for leptocephalus larvae. Concurrent gyre spin-up also affects major currents and slowing of oceanic migration has probably enhanced starvation and predation losses. Local factors, such as unfavourable wind-driven currents, can also affect recruitment of glass eels on continental shelves. In contrast, evidence is discussed that indicates fishing mortality and continental climate change appear to have had lesser impacts. Similar starvation-advection explanations for declines in Japanese eel recruitment are proposed. Predictions for the future are made and multidisciplinary and integrated monitoring and research are recommended for managing eel stocks and fisheries.
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Did lack of spawners cause the collapse of the European eel, Anguilla anguilla?

              N W Dekker (2003)
                Bookmark

                Author and article information

                Contributors
                Journal
                Front Physiol
                Front Physiol
                Front. Physiol.
                Frontiers in Physiology
                Frontiers Media S.A.
                1664-042X
                03 November 2014
                05 January 2015
                2014
                : 5
                : 486
                Affiliations
                [1] 1Institute for Zoology, University of Innsbruck Innsbruck, Austria
                [2] 2Center for Molecular Biosciences, University of Innsbruck Innsbruck, Austria
                Author notes

                Edited by: Josep V. Planas, University of Barcelona, Spain

                Reviewed by: David J. McKenzie, University of Montpellier, France; Reinhold Hanel, Thünen Institute, Germany

                *Correspondence: Bernd Pelster, Institute for Zoology, Leopold-Franzens-University Innsbruck, Technikerstr. 25, A-6020 Innsbruck, Austria e-mail: bernd.pelster@ 123456uibk.ac.at

                This article was submitted to Aquatic Physiology, a section of the journal Frontiers in Physiology.

                Article
                10.3389/fphys.2014.00486
                4297919
                25688210
                23d5e24d-50ad-4fff-b4a0-ffd3d56d98eb
                Copyright © 2015 Pelster.

                This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

                History
                : 02 October 2014
                : 25 November 2014
                Page count
                Figures: 6, Tables: 0, Equations: 2, References: 91, Pages: 10, Words: 9588
                Categories
                Physiology
                Review Article

                Anatomy & Physiology
                swimbladder function,rete mirabile,gas gland cells,european eel,buoyancy,spawning migration

                Comments

                Comment on this article