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CONTEXT: Diadromous fish populations in the Pacific Northwest face challenges along their migratory routes from declining habitat quality, harvest, and barriers to longitudinal connectivity. These stressors complicate the prioritization of proposed management actions intended to improve conditions for migratory fishes including anadromous salmon and trout. OBJECTIVES: We describe a multi-scale hybrid mechanistic-probabilistic simulation model linking migration corridor conditions to fish fitness outcomes. We demonstrate the model’s utility using a case study of salmon and steelhead adults in the Columbia River migration corridor exposed to spatially- and temporally-varying stressors. METHODS: The migration corridor simulation model is based on a behavioral decision tree that governs individual interactions with the environment, and an energetic submodel that estimates the hourly costs of migration. Emergent properties of the migration corridor simulation model include passage time, energy use, and survival. RESULTS: We observed that the simulated fishes’ initial energy density, the migration corridor temperatures they experienced, and their history of behavioral thermoregulation were the primary determinants of their fitness outcomes. Insights gained from use of the model might be exploited to identify management interventions that increase successful migration outcomes. CONCLUSIONS: This paper describes new methods that extend the suite of tools available to aquatic biologists and conservation practitioners. We have developed a 2-dimensional spatially-explicit behavioral and physiological model and illustrated how it can be used to simulate fish migration within a river system. Our model can be used to evaluate trade-offs between behavioral thermoregulation and fish fitness at population scales.

In the original publication of the article, the third author name has been misspelt. The correct name is given in this Correction. The original version of this article was revised.

A systematic approach to customising Homogeneous Multi-Processor (HoMP) architectures is described. The approach involves a novel design space exploration tool and a parameterisable system model. Post-fabrication customisation options for using reconfigurable logic with a HoMP are classified. The adoption of the approach in exploring pre- and post-fabrication customisation options to optimise an architecture's critical paths is then described. The approach and steps are demonstrated using the architecture of a graphics processor. We also analyse on-chip and off-chip memory access for systems with one or more processing elements (PEs), and study the impact of the number of threads per PE on the amount of off-chip memory access and the number of cycles for each output. It is shown that post-fabrication customisation of a graphics processor can provide up to four times performance improvement for negligible area cost.

Memory access patterns common in video processing algorithms, which are unsuited to the GPU (Graphics Processing Unit) memory system, are identified. We develop REDA (Reconfigurable Engine for Data Access) to improve GPU performance for such access patterns, by employing reconfigurable logic for address mapping. It is shown that a sixty times reduction in number of video memory accesses can be achieved for previously unsuited access patterns, with no detriment to well suited patterns. Surprisingly, memory access locality is also improved.