Integrated ecological–economic fisheries models—Evaluation, review and challenges for implementation

Marine ecosystems evolve under many interconnected and area-specific pressures. To fulfil society's intensifying and diversifying needs while ensuring ecologically sustainable development, more effective marine spatial planning and broader-scope management of marine resources is necessary. Integrated ecological-economic fisheries models (IEEFMs) of marine systems are needed to evaluate impacts and sustainability of potential management actions and understand, and anticipate ecological, economic and social dynamics at a range of scales from local to national and regional. To make these models most effective, it is important to determine how model characteristics and methods of communicating results influence the model implementation, the nature of the advice that can be provided and the impact on decisions taken by managers. This article presents a global review and comparative evaluation of 35 IEEFMs applied to marine fisheries and marine ecosystem resources to identify the characteristics that determine their usefulness, effectiveness and implementation. The focus is on fully integrated models that allow for feedbacks between ecological and human processes although not all the models reviewed achieve that. Modellers must invest more time to make models user friendly and to participate in management fora where models and model results can be explained and discussed. Such involvement is beneficial to all parties, leading to improvement of mo-dels and more effective implementation of advice, but demands substantial resources which must be built into the governance process. It takes time to develop effective processes for using IEEFMs requiring a long-term commitment to integrating multidisciplinary modelling advice into management decision-making.</p

Methodological Proposal for the Hydraulic Design of Labyrinth Weirs

A labyrinth weir allows for higher discharge capacity than conventional linear weirs, especially at low hydraulic heads. In fact, this is an alternative for the design or rehabilitation of spillways. It can even be used as a strategy in problems related to dam safety. A sequential design method for a labyrinth weir is based on optimal geometric parameters and the results of discharge flow analysis using Computational Fluid Dynamics and the experimental studies reported in the literature. The tests performed were for weirs with values of HT/P ≤ 0.8 and for angles of the cycle sidewall of 6° ≤ α ≤ 20°. The results of the discharge coefficient are presented as a family of curves, which indicates a higher discharge capacity when HT/P ≤ 0.17. Four aeration conditions are identified with higher discharge capacity when the nappe is adhering to the downstream face of the weir wall and lower discharge capacity when the nappe is drowned. Unstable flow was present when 12° ≤ α ≤ 20°, with a greater presence when the nappe was partially aerated and drowned. The interference of the nappe is characterized and quantified, reaching up to 60% of the length between the apex, and a family of curves is presented as a function of HT/P in this respect. Finally, a spreadsheet and a flowchart are proposed to support the design of the labyrinth type weir