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| Registros recuperados: 96 | |
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| Rochet, Marie-joelle; Trenkel, Verena; Rice, Jake. |
| Currently many multi-year management plans are being developed either for rebuilding depleted stocks or for avoiding difficult negotiations when management decisions must be revisited on a regular basis. Management plans are commonly evaluated by intensive model simulations that describe the ecological and economic dynamics, and the management loop. Under the results-based management paradigm, the fishing industry or particular fishing sectors will develop their own management plans, potentially leading to a huge number of plans to be evaluated. Guidelines for evaluating the plans on a qualitative level before launching quantitative evaluations will be essential. Here we propose a framework for evaluating management strategies in a qualitative way. A... |
| Tipo: Text |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00029/13988/11166.pdf |
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| Benoit, Eric; Rochet, Marie-joelle. |
| A new time-dependent continuous model of biomass size spectra is developed. In this model, predation is the single process governing the energy flow in the ecosystem, as it causes both growth and mortality. The ratio of predator to prey is assumed to be distributed: predators may feed on a range of prey sizes. Under these assumptions, it is shown that linear size spectra are stationary solutions of the model. Exploited fish communities are simulated by adding fishing mortality to the model: it is found that realistic fishing should affect the curvature and stability of the size spectrum rather than its slope. |
| Tipo: Text |
Palavras-chave: Predation; Mortality; Growth; Biomass size spectrum; Allometry. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/publication-665.pdf |
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| Morin, Jocelyne; Bertrand, Jacques; Cochard, Marie-laure; Coppin, Franck; Leaute, Jean-pierre; Lobry, Jeremy; Mahe, Jean-claude; Poulard, Jean-charles; Rochet, Marie-joelle; Schlaich, Ivan; Souplet, Arnauld; Trenkel, Verena; Vaz, Sandrine; Verin, Yves. |
| Since about twenty years, Ifremer have carried out fishery surveys along the French coasts. A dynamic indicator-based approach to the assessment of multi-stock fisheries has been applied to these data series. Reference points for non-commercial populations and community indicators are seldom available, but reference directions are well established: it is known whether fishing will increase or decrease the indicator, hence the direction that should be avoided. A set of simple indicators of fishing impacts on fish populations and communities were estimated from time-series data provided by scientific surveys (population abundance and average length, community total biomass and number, average length and weight, and size spectrum). Trends in these indicators... |
| Tipo: Text |
Palavras-chave: Communauté; Population; Indicateurs; Campagnes scientifiques; Pêcheries multi spécifiques; Approche écosystémique pour la gestion des pêches. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/rapport-7293.pdf |
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| Reecht, Yves; Rochet, Marie-joelle; Trenkel, Verena; Jennings, S.; Pinnegar, J. K.. |
| An ecomorphological method was developed, with a focus on predation functions, to define functional groups in the Celtic Sea fish community. Eleven functional traits, measured for 930 individuals from 33 species, led to 11 functional groups. Membership of functional groups was linked to body size and taxonomy. For seven species, there were ontogenetic changes in group membership. When diet composition, expressed as the proportions of different prey types recorded in stomachs, was compared among functional groups, morphology-based predictions accounted for 28-56% of the interindividual variance in prey type. This was larger than the 12-24% of variance that could be explained solely on the basis of body size. (C) 2013 The Fisheries Society of the British Isles |
| Tipo: Text |
Palavras-chave: Ecomorphology; Functional traits; Predation strategy; Trophic functions. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00152/26294/24831.pdf |
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| Catchpole, T. L.; Feekings, J. P.; Madsen, N.; Palialexis, A.; Vassilopoulou, V.; Valeiras, J.; Garcia, T.; Nikolic, Natacha; Rochet, Marie-joelle. |
| Discards refer to the part of the catch not retained on board during commercial fishing operations, but returned to the sea. The proposed European Union Common Fisheries Policy reform, to be implemented in 2014, sets out a gradual elimination of discards by reducing unwanted catches and ensuring that all catches are landed. To develop successful discard mitigation measures, it is necessary to identify the reasons for discarding. Here, we have developed a simple model that can be applied to data from observer programmes (ObsPs) to establish the contribution of different drivers of discarding behaviour. The analysis makes inferences on the causes of discarding by partitioning discards into four categories based on the length of the fish and the associated... |
| Tipo: Text |
Palavras-chave: CFP; Discards; Fishers market; Quota. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00159/27030/26202.pdf |
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| Trenkel, Verena; Rochet, Marie-joelle. |
| P>1. Metrics have become a standard way for summarizing environmental monitoring results. Different metrics react differently to natural variations and human-induced stressors. We suggest that combined analysis of time trends in selected biological metrics allows identification of biological processes (e.g. individual growth, mortality or recruitment) that have changed (increased or decreased) persistently. Alternatively, time trends in the abundance of sensitive species could indicate changes in environmental stressors. 2. We calculate the joint likelihood of time trends in three metrics and use it to evaluate the evidence in the data for different combinations of metric time trends. A simulation study provides guidelines for interpreting... |
| Tipo: Text |
Palavras-chave: Generalized additive model; Indicators; Likelihood principle; Quadratic programming; Survey data. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00008/11926/8988.pdf |
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| Brind'Amour, Anik; Rochet, Marie-joelle; Ordines, Francesc; Hosack, Geoff; Berthele, Olivier; Merigot, Bastien; Carbonara, Pierluigi; Follesa, Maria Cristina; Jadaud, Angelique; Lefkaditou, Evgenia; Maiorano, Porzia; Peristeraki, Panagiota; Mannini, Alessandro; Rabiller, Manuella; Spedicato, Maria Teresa; Tserpes, George; Trenkel, Verena. |
| Functional groups are sets of species that play a similar role in a food web. We defined functional groups of fish species based on their morphological characteristics, while using expert knowledge for invertebrates. We measured 9 morphological traits of 72 fish species, and carried out multivariate analyses to assign fish species to functional groups. The analysis identified 9 trait-based fish functional groups to which were added 3 expert-based invertebrate functional groups. The habitat (position in the water column) and potential diet of each group were identified from the literature. Using the MEDITS bottom trawl survey data collected at 10 to 800 m depth, we calculated relative change in the 12 fish and invertebrate functional group biomasses for 12... |
| Tipo: Text |
Palavras-chave: Morphological traits; Community models; Functional network; Functional groups; Mediterranean Sea; Temporal trends; Fish; Shellfish. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00363/47382/47475.pdf |
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| Bertrand, Jacques; Cochard, Marie-laure; Coppin, Franck; Leaute, Jean-pierre; Lobry, Jeremy; Mahe, Jean-claude; Morin, Jocelyne; Poulard, Jean-charles; Rochet, Marie-joelle; Schlaich, Ivan; Souplet, Arnauld; Trenkel, Verena; Verin, Yves; SIH-C. |
| The integration of fishing management into the ecosystemic approach has been recommended for many years by international consultative bodies; it is also written into international conventions and agreements. The implementation of the ecosystemic approach involves the development of programmes for monitoring exploited ecosystems in order to measure the effects of management steps. Plotting the results of these observations for operational reasons requires formalizing summary performance indicators. IFREMER has carried out halieutic observation campaigns for some twenty years along the coasts of France from oceanographic ships and chartered ships. The objective of these campaigns is to produce abundance indices of species that are of halieutic interest.... |
| Tipo: Text |
Palavras-chave: Ecosystem; Indicating; Scientific survey; Scientific research; Fishing; English Channel; Bay of Biscay; France; Shellfish; Fish; Invertébrés; Poissons; Ecosystème; Indicateur; Campagne océanographique; Recherche scientifique; Pêche halieutique; Pêche; Mer du nord; Golfe de gascogne; Manche; France. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/rapport-2327.pdf |
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| Trenkel, Verena; Rochet, Marie-joelle; Mesnil, Benoit. |
| Traditional advice for fisheries management, especially in the ICES world, focuses on short-term stock projections relative to reference points. Primarily, two numbers, spawning-stock biomass and fishing mortality rate, are considered in the advice, although a range of biological processes are included in the stock assessment models. We propose an alternative form of final advice that would not rely on stock predictions and only two numbers, but on a suite of indicators that are combined to provide stock assessment and management advice. For a single stock, the approach consists of monitoring a set of indicators of population state and fishing pressure. Stock reference status at some time in the past is assessed, based on these indicators and/or other... |
| Tipo: Text |
Palavras-chave: Scientific advice; Indicators; Fisheries management. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2619.pdf |
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| Rochet, Marie-joelle; Rice, Jake C.. |
| Simulation-based management strategy evaluation is a valuable tool, when appropriately implemented. Implementation, however, may not always have been appropriate, and some reasons are provided why perhaps there is incomplete faith in certain of its technical aspects, such as knowing the distribution of the parameters of population processes from the information in limited datasets. A management strategy that has been evaluated by simulation should not be used as an "autopilot", because even the most competent of experts can develop autopilots with imperfect and incomplete knowledge of reality, and all information should be incorporated when decisions have to be made. |
| Tipo: Text |
Palavras-chave: Decision-making; Distribution models; Management strategy evaluation. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00002/11278/7922.pdf |
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| Cornou, Anne-sophie; Dimeet, Joel; Tetard, Alain; Gaudou, Olivier; Quinio-scavinner, Marion; Fauconnet, Laurence; Dube, Benoit; Rochet, Marie-joelle. |
| Ce document est une synthèse des informations collectées en 2013 à bord des navires de pêche professionnelle dans le cadre de l'action ObsMer. Cette action vise à observer in situ l'activité de pêche et l'ensemble de la capture, particulièrement la partie non retenue, en identifiant les espèces capturées, les tonnages par espèce et en prenant des mesures de tailles. |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00247/35856/34377.pdf |
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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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| Rochet, Marie-joelle; Catchpole, Tom; Cadrin, Steve. |
| Discarding is considered by many as an important problem in world fisheries. In many regions, data collection onboard commercial vessels has intensified, and the understanding of both human and ecological drivers of discards is improving quickly. Discarding patterns vary widely across regions, fisheries, gears, and species. Fishers' responses to regulations and markets explain these complex patterns, on top of resource availability partly driven by environmental fluctuations. This expanded knowledge base provides an appropriate basis for discussing the discard mitigation measures proposed in various settings. In September 2012, a theme session was convened at the ICES Annual Science Conference in Bergen, Norway, to discuss these issues. This themed set of... |
| Tipo: Text |
Palavras-chave: Bycatch and discards; Catch quotas; Compliance; Landing obligation; Landing quotas; Market incentives; Minimum landing sizes; Onboard observer programmes; Selectivity. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00202/31353/29911.pdf |
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| Reid, David G; Calderwood, Julia; Afonso, Pedro; Bourdaud, Pierre; Fauconnet, Laurence; Gonzalez-irusta, José Manuel; Mortensen, Lars O; Ordines, Francesc; Lehuta, Sigrid; Pawlowski, Lionel; Plet-hansen, Kristian S; Radford, Zachary; Robert, Marianne; Rochet, Marie-joelle; Rueda, Lucia; Ulrich, Clara; Vermard, Youen. |
| Under the Landing Obligation (LO) fishers will need to reduce or land fish that were previously discarded. In this chapter we look at how they might be able to do that by summarising a number of studies conducted in various European regions. We start by describing a series of “challenge” trials where fishers tried to reduce their discards by whatever (legal) means they thought best. In some cases, they were able to reduce unwanted catches, in others they were less successful. We also interviewed fishers not involved in the trials to ask them what they thought they could do. We explore their approaches which generally fell into three categories: more selective gear; tactical and strategic changes; and management changes. Scientific data (surveys, landings,... |
| Tipo: Text |
Palavras-chave: Challenge trials; Decision support tools; Discard avoidance; Fine scale mapping; Fish distribution; Fishers; Fishing strategies; Hot-spot maps. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00473/58428/61004.pdf |
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| Registros recuperados: 96 | |
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