Peacock bass mortality associated with catch-and-release sport fishing in the Negro River, Amazonas State, Brazil

Sport fishing for peacock bass Cichla spp. in the Brazilian Amazon has increased in popularity and attracts anglers who generate significant economic benefits in rural regions. The sustainability of this fishery is partly dependent on the survival of fish caught through catch-and-release fishing. The objective of this work was to investigate, hooking mortality of Cichla spp., including speckled peacock bass (C. temensis Humbolt), butterfly peacock bass (C. orinocensis Humbolt), and popoca peacock bass (C. monoculus Agassiz) in the basin of the Negro River, the largest tributary of the Amazon River. Fish were caught at two different sites using artificial lures, transported to pens anchored in the river and monitored for 72 hours. A total of 162 individual peacock bass were captured and hooking mortality (mean % ± 95% confidence intervals) was calculated. Mean mortality was 3.5% (± 5.0), 2.3% (± 3.5) and 5.2% (± 10.2) for speckled peacock bass, butterfly peacock bass, and popoca peacock bass, respectively. Lengths of captured fish ranged from 26 to 79 cm (standard length), however, only fish under 42 cm died. This research suggests that catch-and-release sport fishing of peacock bass does not result in substantial mortality in the Negro River basin.A pesca esportiva de tucunarés Cichla spp., na Amazônia brasileira, aumentou em popularidade nos últimos anos e tem atraído pescadores esportivos que geram benefícios econômicos para essa região. Entretanto, a sustentabilidade dessa pescaria depende em parte da sobrevivência dos peixes capturados por meio da prática do pesque e solte. O objetivo deste trabalho foi avaliar a mortalidade de Cichla spp., incluindo o tucunaré paca (C. temensis Humbolt), o borboleta (C. orinocensis Humbolt) e o popoca (C. monoculus Agassiz) em dois locais na bacia do rio Negro, o maior tributário do rio Amazonas. Os peixes foram capturados por variados tipos de iscas artificiais e posteriormente monitorados em viveiros construídos no próprio rio por 72 horas. Um total de 162 tucunarés foi capturado, e as mortalidades (% ± intervalo de confiança 95%) foram calculadas. A mortalidade foi 3,5% (± 5,0), 2,3% (± 3,2) e 5,2% (±10,2) para o paca, o borboleta e o popoca, respectivamente. O comprimento padrão dos peixes capturados variou de 26 a 79 cm, mas apenas os peixes menores até 42 cm morreram. A pesquisa sugere que a pesca esportiva não causou substancial mortalidade na população de Cichla spp. na bacia do rio Negro

Progress from ASDEX Upgrade experiments in preparing the physics basis of ITER operation and DEMO scenario development

An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling of AUG discharges was established which is able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In the plasma center, theoretical predictions on plasma current redistribution by a dynamo effect were confirmed experimentally. For core transport, the stabilizing effect of fast ion distributions on turbulent transport is shown to be important to explain the core isotope effect and improves the description of hollow low-Z impurity profiles. The L-H power threshold of hydrogen plasmas is not affected by small helium admixtures and it increases continuously from the deuterium to the hydrogen level when the hydrogen concentration is raised from 0 to 100%. One focus of recent campaigns was the search for a fusion relevant integrated plasma scenario without large edge localised modes (ELMs). Results from six different ELM-free confinement regimes are compared with respect to reactor relevance: ELM suppression by magnetic perturbation coils could be attributed to toroidally asymmetric turbulent fluctuations in the vicinity of the separatrix. Stable improved confinement mode plasma phases with a detached inner divertor were obtained using a feedback control of the plasma β. The enhanced D α H-mode regime was extended to higher heating power by feedback controlled radiative cooling with argon. The quasi-coherent exhaust regime was developed into an integrated scenario at high heating power and energy confinement, with a detached divertor and without large ELMs. Small ELMs close to the separatrix lead to peeling-ballooning stability and quasi continuous power exhaust. Helium beam density fluctuation measurements confirm that transport close to the separatrix is important to achieve the different ELM-free regimes. Based on separatrix plasma parameters and interchange-drift-Alfvén turbulence, an analytic model was derived that reproduces the experimentally found important operational boundaries of the density limit and between L- and H-mode confinement. Feedback control for the X-point radiator (XPR) position was established as an important element for divertor detachment control. Stable and detached ELM-free phases with H-mode confinement quality were obtained when the XPR was moved 10 cm above the X-point. Investigations of the plasma in the future flexible snow-flake divertor of AUG by means of first SOLPS-ITER simulations with drifts activated predict beneficial detachment properties and the activation of an additional strike point by the drifts

Overview of physics studies on ASDEX Upgrade

The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO

Fast and efficient algorithms for computational electromagnetics on GPU architecture

Integral formulations, suitable for the numerical solution of quasi-magnetostatic (eddy currents) problems in large and complex 3D domains, require specific post-processing tools to compute the effects of known current density distributions over elementary geometric entities (both mesh elements and field sources). The aim of this paper is to present a fast and robust implementation on a GPU architecture of an accurate algorithm for the computation of magnetic field and vector potential components

Simulation of space charge compensation in a multibeamlet negative ion beam

none5norestrictedSartori, E; Maceina, T.J.; Veltri, P.; Cavenago, M.; Serianni, G.Sartori, Emanuele; Maceina, T. J.; Veltri, Pierluigi; Cavenago, M.; Serianni, Gianluig

Use of virtual actuators in ASDEX Upgrade control

Actuator management is an essential part of a modern tokamak plasma control system. It has to deal with a large number of control task simultaneously, needs to be able to operate close to stability limits and to avoid disruptions. In the ASDEX Upgrade tokamak experiment, the process of actuator management development is ongoing. As a first step, we have removed direct assignement of physical actuators to controllers responsible for the control task execution. Instead, the controller is communicating to the so-called virtual actuator, which groups an arbitrary number of actuators of the same type (so far ECRH only) and distributes the controller command between them. The virtual actuator has been implemented and used on ASDEX Upgrade in the 2019 experimental campaign. It gave valuable contributions to several physics experiments. First, the implementation of the virtual actuator enabled beta(p) control by ECRH power, which is of interest especially for I-mode and ELM-free H-mode discharges. Second, it was used in the electron temperature control experiments, which is a useful control tool for transport studies. Third, the concept was used for the density limit disruption avoidance experiments where central ECRH power is applied to recover the plasma from a disruptive zone. The current paper describes the use of the virtual actuator in these cases and based on the gained experience, it suggests future developments and improvements of the virtual actuator on ASDEX Upgrade discharge control system