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| De Lara, Michel; Doyen, Luc; Guilbaud, Therese; Rochet, Marie-joelle. |
| Fisheries management agencies have to drive resources on sustainable paths, i.e. within defined boundaries for an indefinite time. The viable-control approach is proposed as a relevant method to deal with sustainability. We analyse the ICES precautionary approach (PA) by means of the notion of viability domain, and provide a mathematical test for sustainability. It is found that the PA based on spawning-stock biomass (SSB) and fishing mortality (F) indicators is sustainable only when recruits make a significant contribution to SSB. In this case, advice based upon SSB, with an appropriate reference point, is sufficient to ensure sustainability. In all other cases, SSB is not a sufficient metric of stock productivity and must be complemented with other... |
| Tipo: Text |
Palavras-chave: Viability; Sustainable management; Indicators; ICES precautionary approach. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2821.pdf |
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| De Lara, Michel; Doyen, Luc; Guilbaud, Therese; Rochet, Marie-joelle. |
| This paper deals with the control of nonlinear systems in the presence of state and control constraints for discrete-time dynamics in finite-dimensional spaces. The viability kernel is known to play a basic role for the analysis of such problems and the design of viable control feedbacks. Unfortunately, this kernel may display very nonregular geometry and its computation is not an easy task in general. In the present paper, we show how monotonicity properties of both dynamics and constraints allow for relevant analytical upper and lower approximations of the viability kernel through weakly and strongly invariant sets. An example on fish harvesting management illustrates some of the assertions. |
| Tipo: Text |
Palavras-chave: Monotonicity; Invariance; Viability; State constraints; Control. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2405.pdf |
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