Evol Ecol Res 6: 1123-1144 (2004)     Full PDF if your library subscribes.

Colonization of the freshwater environment by a marine invader: how to cope with warm summer temperatures?

Franz Hölker,* Sven Volkmann, Christian Wolter, Peter L.M. van Dijk and Iris Hardewig

Leibniz-Institute of Freshwater Ecology and Inland Fisheries, PO Box 850119, 12561 Berlin, Germany

Author to whom all correspondence should be addressed.
e-mail: hoelker@igb-berlin.de


The burbot Lota lota (L.) is the only member of the cold-stenothermal marine family Gadidae that invaded freshwater. To evaluate the evolutionary strategy allowing the invasion of freshwater habitats with high temperature amplitudes, we determined seasonal variations of the energy budget for juvenile burbot from the River Oder, Germany. Food consumption during summer was not sufficient to meet the animal’s energetic requirements. During winter and spring, energy uptake surpassed the metabolic energy flux and left surplus energy for growth. Burbot growth is maintained throughout the year by two mechanisms: (1) growth that is reflected predominantly in length throughout the summer, when energy-rich liver tissue must be metabolized to provide energy, and (2) a synthesis of liver reserves during winter, when energy uptake exceeds energy dissipation. In contrast to most freshwater fish, which reduce growth rates during the winter months, the evolutionary burden of being cold-adapted, inherited from its marine ancestors, enables L. lota to maintain somatic growth throughout the year.

Keywords: bioenergetics, cold-stenotherm, Gadidae, growth, Lota lota, temperature tolerance.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2004 Franz Hölker. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.