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This volume presents a synthesis of basic biological and conservation data for more than 30 species of sturgeons (Acipenseridae), paddlefishes (Polyodontidae) and their fossil allies in the order Acipenseriformes. Since the Jurassic, the four families of sturgeon-like fish have been restricted to the Holarctic, where until very recently they flourished in most major river systems. Today, however, virtually all species of sturgeons and paddlefishes face difficult conservation issues. Papers in the first section of this volume examine paleontology, systematics, evolution and basic biology of Acipenseriformes. The second section of this volume details current conservation status for most of the world's living species of Acipenseriformes. These papers mark the first attempt to make such a global review of recent data from across the northern hemisphere. The emerging picture is discouraging, for negative anthropogenic impacts range from overfishing to water pollution, to dams and water diversion projects, and all species are threatened to some degree. The third section of the volume considers specific human impacts and responses to conservation issues. These include: the Aral Sea ecological disaster and its impact on native sturgeons; a review of methods for restoring sturgeon populations; the use of molecular techniques in developing conservation strategies; the extreme sensitivity of sturgeons and paddlefishes to overfishing; and the history of a recently convicted caviar poaching ring. The volume's summary reviews the status of all extant species and notes future directions for research on behavior, ecology and population biology that could lead to better co-ordinated international conservation efforts.
This eleventh edition was developed during the encyclopaedia's transition from a British to an American publication. Some of its articles were written by the best-known scholars of the time and it is considered to be a landmark encyclopaedia for scholarship and literary style.
Two events have recently improved the prospects of protecting fish and their environment in Switzerland: the acceptance of a new Federal Water Protection Law in the plebiscite of May 17th 1992, and the new Federal Legislation on Fisheries, in force since January 1st 1994. With this legal framework, the possibilities for protection of nature and landscape have now considerably improved in Switzerland. The most important aims of the Federal Law on Water Protection are to safeguard the natural habitats of the native flora and fauna and water as the habitat of aquatic organisms. This includes not only the preservation or restoration of water quality in lakes and rivers, but also, in rivers used for hydroelectricity, irrigation or as industrial or other water supplies, the maintenance of sufficient water to fulfill the minimal requirements for fish. However, good quality water in sufficient quan tities alone is not enough to guarantee the survival of fish. Intact fish habitats comprise various phYsical structures including plenty of hiding places, hunting grounds, reproduction and nursery areas within suitable distances from each other. This third aspect of conservation and restoration of aquatic habitats is a central point in the new Federal Law on Fisheries. Whereas the former versions of this law were more concerned with fishery regulations, the recent legislation defines new areas of responsibility for the federal and the cantonal governments.