Summary
Since the European sturgeon (Acipenser sturio) is one of the most highly endangered fish species worldwide with only one population known to still exist in the Gironde River, France, it is ...attempted to facilitate in‐situ and ex‐situ protection of the species through coordinated efforts within the former range. To increase the collaborative approach in safeguarding and restoration of the species’ population the Bern Convention has adopted an Action Plan (AP) at the Standing Committee meeting in November 2007. Based on this agreement, the member states to the Bern Convention are requested to develop national APs addressing the critical issues for its conservation. This paper discusses in detail the prerequisites for the development of such a national AP, thus focusing on the complex structures in the German Federal and Regional governance system, the stakeholder involvement required, as well as the dynamics of a process unprecedented in any fish species under this convention. For the national AP the governmental agencies for nature conservation and for fisheries, the regional and national stakeholders such as commercial and recreational fisheries, inland navigation administration, port authorities, river catchment management units, recreational water users and environmental conservation NGO’s have to be brought together, overcoming major barriers to allow a constructive dialogue leading towards a common problem analysis. As a result, the German national AP is intended to provide a common basis for the future protection attempts, outlining the main focal points for necessary activities. As such it also serves as the framework for the management plans for the river systems considered suitable for the attempts to remediate populations of the European sturgeon in German and other European Rivers in a joint effort with the French partners.
We analysed ~310 records of river lampreys Lampetra fluviatilis (Linnaeus, 1758) (~19977663 specimens) and 54 records of sea lampreys Petromyzon marinus Linnaeus, 1758 (~86 specimens) for the ...southern parts of ICES Subdivisions 22 and 24 to 26 in the Baltic Sea covering the period 1649 to 2005. Most sea lamprey records came from Subdivisions 22 and 24. The majority of river lamprey records stem from Subdivisions 24 and 26. We found no distinct temporal trend for sea lamprey stock development. However, a long-term trend showing decreasing catches of river lamprey was detected, indicating a stock decrease of this species from 1887 to 1999. The largest numbers of lamprey (largely river lamprey but may include some sea lamprey as species were not distinguished in the past) were caught in the period 1890 to 1919. Approximately 82% of the total lamprey catch in our study area was made in Subdivision 26. Roughly 65.3% of the mean annual yield of lampreys came from the lower Vistula River, the Vistula Lagoon and the Bay of Gdansk. The river lamprey was mainly distributed in estuarine and coastal marine areas. Offshore records of sea lamprey were also rare. From 1990 to 2005, most river lamprey records and recorded individuals originated from the Szczecin Lagoon and its adjacent waters, demonstrating the present importance of these waters for their spawning migrations. Of 9 known river lamprey spawning sites, 5 were found in the Peene River system which flows into the Szczecin Lagoon. At present, no sea lamprey reproduction site is known from rivers of the German Baltic Sea area. A rebuilding programme is required for the river lamprey; this should definitely contain measures to restore lost spawning sites and the connectivities within the river systems where spawning populations still occur. Protected areas in estuarine waters with important lamprey migration routes may be an additional measure for the conservation of these anadromous species.
Observation of coasting beam at the HERA proton-ring Ehret, K; Funcke, M; Issever, S ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2001, 2001-1-00, Letnik:
456, Številka:
3
Journal Article
Recenzirano
We present data collected with the HERA-B wire target which prove the existence of coasting beam at the HERA proton storage ring. The presented measurements show a strong evidence that the proton ...machine operation contribute to the coasting beam production, which seems to be not dominated by target impacts.
Summary
The data of sturgeon catches in German and adjacent waters since 1980 have been collected from the major river systems and coastal waters in Germany and neighbouring countries. Over the past ...10 years records on catches of exotic sturgeon species increasingly occur in the commercial and recreational fisheries, including the following species: Acipenser baerii, A. gueldenstaedtii as well as hybrids from different parental species such as H. huso x A. ruthenus, A. baerii x A. ruthenus. A total of 227 records are reported, including data on their distribution. Accidental or deliberate introductions of sturgeons have been mediated by aquaculture and/or petfish‐industries. Their occurrence is discussed in relation to plans for the re‐establishing of the native A. sturio.
Using the HERA-B detector, the b (b) over bar production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The b (b) over bar production was tagged via ...inclusive bottom quark decays into J/psi by exploiting the longitudinal separation of J/psi --> l(+)l(-) decay vertices from the primary proton-nucleus interaction. Both e(+)e(-) and mu(+)mu(-) channels have been reconstructed and the combined analysis yields the cross section sigma(b (b) over bar) = 32(-12)(+14)(stat) (+6)(-7)(sys) nb/nucleon.
Inclusive differential cross sections dsigma(pA)/dx(F) and dsigma(pA)/dp(t)(2) for the production of K-S(0), Lambda, and (&ULambda;) over bar particles are measured at HERA in proton-induced ...reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to roots = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dsigma(pA)(K-S(0))/dsigma(pA)(Lambda) and dsigma(pA)((&ULambda;) over bar)/dsigma(pA) (Lambda) are measured to be 6.2 +/- 0.5 and 0.66 +/- 0.07, respectively, for x(F) approximate to -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions da,Ald t also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections sigma(pA) on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon sigma(pN) are compared with results obtained at other energies.
Sturgeon catches in major river systems and coastal waters of Germany since 1980 show increasing records of exotic sturgeon species in both recreational and commercial fisheries. The incidence of ...hybrids also has increased. Aquaculture and pet fish industries are responsible for accidental or deliberate introductions of exotic sturgeon species. The occurrence of these species is discussed in relation to plans to re-establish a native sturgeon, Acipenser sturio in German waters. There is concern that hybridization may pose a risk to the native species' gene pool.
The historic range and status of A. sturio in the tributaries to the North Sea, its past utilization and its population development is presented to the extent that it can be derived from available ...fisheries data. The alteration in fishing techniques and fishing sites, from a strictly riverine fishery to coastal fishery average in the 1880s and subsequently, the increased marine catch is illustrated. Its effects on fish size as well as on the population are documented. While the fishery initially targeted the fish for meat over several hundred years, caviar became an additional driver to the fishery after 1840 in Germany. The endpoint of a targeted fishery occurred in the early twentieth century for the majority of rivers. River constructions to improve navigation, pollution, as well as overharvest interlinking with insufficient protection led to the extirpation of the species in the North Sea and its tributaries.
Sturgeon catches (n = 256) from 1981-1999 reported mainly by commercial fishermen and anglers in German, Polish, and Dutch coastal waters and tributaries were analysed. During the study period, 20 % ...of catches were reported from coastal waters and 65 % from rivers and estuaries of large river systems, including the Odra, Elbe, Rhine and Weser. The data indicate that, from 1981- 1993, there was a major decline in the Atlantic sturgeon Acipenser sturio L., 1758, and an increase in the total catches of non-indigenous sturgeon species. The Siberian sturgeon Acipenser baerii Brandt, 1869, the Russian sturgeon Acipenser gueldenstaedtii Brandt & Ratzeberg, 1833, and various hybrids dominated. Occasional catches of the white sturgeon Acipenser transmontanus Richardson, 1836 and the sterlet Acipenser ruthenus L., 1758 were also reported. During the study period, significant changes in species composition and distribution of catches were observed. The predominance of non-indigenous sturgeon species is a result of the increasingly intensive sturgeon aquaculture activities in Germany, Poland, and the Netherlands. The most frequently reared species now dominate the catches. In addition to these escapees from fish farms, several intentional releases of sturgeons were reported. The results show that introduced exotic sturgeon species may thrive under certain natural conditions. Therefore, they may interfere with restoration efforts for the native A. sturio, competing for habitat and introducing diseases and hybridization. Se analizaron las capturas de esturiones (n = 256) entre 1981 y 1999 proporcionadas principalmente por pescadores profesionales y deportivos en las costas alemanas, polacas y holandesas, y en los sistemas fluviales que desembocan en ellas. En el periodo de estudio, el 20 % de las capturas correspondió a aguas litorales y el 65 % a ríos y estuarios de los grandes sistemas fluviales, incluidos los ríos Oder, Elba, Rin y Weser. Los datos indican que entre 1981 y 1993 tuvo lugar el mayor declive del esturión atlántico Acipenser sturio L., 1758 y un incremento en las capturas totales de las especies alóctonas de esturiones. Predominaron las capturas de esturión siberiano Acipenser baerii Brandt, 1869, esturión ruso Acipenser gueldenstaedtii Brandt & Ratzeberg, 1833 y varios híbridos. También se registraron capturas ocasionales de esturión blanco Acipenser transmontanus Richardson, 1836 y esterlete Acipenser ruthenus L., 1758. En el periodo de estudio se observaron cambios significativos en la composición de especies y en la distribución de las capturas. El predominio de las especies alóctonas de esturiones es el resultado de las crecientes actividades en la acuicultura intensiva de esturión en Alemania, Polonia y Países Bajos. Las especies cultivadas más frecuentemente dominan ahora las capturas. Además de estas fugas de las piscifactorías, se han registrado varias sueltas intencionadas. Los resultados muestran que las especies de esturiones exóticas introducidas pueden prosperar en ciertas condiciones naturales. Por esta razón, pueden interferir en los esfuerzos de restauración de la especie autóctona A. sturio, compitiendo por el hábitat e introduciendo enfermedades e hibridación.
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