A review of the past and present status of anadromous fish species in the Netherlands: is restocking the Rhine feasible?

The paper reviews the past, present and future of eight anadromous fish species inhabiting the Lower Rhine (The Netherlands), viz. -sturgeon (Acipenser sturio), whitefish and houting (Coregonus lavaretus, C. oxyrinchus), smelt (Osmerus eperlanus), allis and twaite shad (Alosa alosa, A. fallax), sea trout (Salmo trutta) and salmon (Salmo salar). All species are under threat or became extinct (e.g. sturgeon, allis shad). It is not possible to single out a specific factor for the decline or disappearance. A combination of factors is responsible, as the degradation of the spawning and nursery areas, river correction for shipping, building of sluices and hydropower dams, extraction of sand and gravel and river pollution. The likelihood that a species will return via natural recovery, or restocking is assessed. The return of the sturgeon is unlikely. Present observations of sturgeon can be attributed to releases of unwanted sturgeon hybrids. A natural stock of coregonids in Dutch waters seems not feasible any more due to irreversible habitat degradation. Present day catches originate from German releases. The anadromous smelt, heavily reduced in numbers, still inhabits some of our waters, the non-migratory smelt is still very common. The allis shad is extinct and unlikely to recover. The species never spawned in the Dutch part of the Rhine. Twaite shad, declining in numbers, are still observed in the lower reaches of Rhine and Meuse. Sea trout is presumably still present in the same varying numbers as before. Spawning in our waters has not been documented. The salmon, once fished in large numbers, is now the subject of restocking programmes in Germany. Observations of individuals can partly be attributed to these programmes but also to straying salmon. Restocking programmes should be considerably improved before noticeable success is to be met

Partonic flow and phi-meson production in Au+Au collisions at root s(NN)=200 GeV

We present first measurements of the phi-meson elliptic flow (v(2)(p(T))) and high-statistics p(T) distributions for different centralities from root s(NN) = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v(2) of the phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Omega to those of the phi as a function of transverse momentum is consistent with a model based on the recombination of thermal s quarks up to p(T)similar to 4 GeV/c, but disagrees at higher momenta. The nuclear modification factor (R-CP) of phi follows the trend observed in the K-S(0) mesons rather than in Lambda baryons, supporting baryon-meson scaling. These data are consistent with phi mesons in central Au+Au collisions being created via coalescence of thermalized s quarks and the formation of a hot and dense matter with partonic collectivity at RHIC

System-Size Independence of Directed Flow Measured at the BNL Relativistic Heavy-Ion Collider

We measure directed flow (v(1)) for charged particles in Au + Au and Cu + Cu collisions at root s(NN) = 200 and 62.4 GeV, as a function of pseudorapidity (eta), transverse momentum (p(t)), and collision centrality, based on data from the STAR experiment. We find that the directed flow depends on the incident energy but, contrary to all available model implementations, not on the size of the colliding system at a given centrality. We extend the validity of the limiting fragmentation concept to v(1) in different collision systems, and investigate possible explanations for the observed sign change in v(1)(p(t))