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| Registros recuperados: 74 | |
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| Marchal, Paul; Poos, Jan-jaap; Quirijns, Floor. |
| This study has investigated some properties of fishermen's foraging, using Levy flights theory. The case studies examined were a selection of North Sea Dutch and French vessels, for which catch and effort data were collected on a haul-by-haul basis. Foraging behavior could reasonably be represented by a Levy flight process, characterized by an exponentiation factor mu, for both fleets. The properties of fishers' foraging were further investigated for the Dutch fleet using time series analysis. Optimal foraging was found with mu = 1.5, suggesting a slow recovery dynamics of the stocks being harvested. Efficient foraging led to high value per unit effort, while the knowledge of fishing grounds with high stock density is shown to increase foraging efficiency... |
| Tipo: Text |
Palavras-chave: Haul by haul data; Foraging; Fishing effort; Levy flights; Fleet behavior. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2314.pdf |
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| Marchal, Paul; Andersen, B; Bromley, D; Iriondo, A; Mahevas, Stephanie; Quirijns, F; Rackham, B; Santurtun, M; Tien, N; Ulrich, Clara. |
| The scope of this paper is to quantify, for a wide selection of European fisheries, fishing tactics and strategies and to evaluate the benefits of adjusting the definition of. fishing effort using these elements. Fishing tactics and strategies were identified by metiers choices and a series of indices. These indices have been derived to reflect shifts in tactics (within a fishing trip) and in strategies (within a year). The Shannon-Wiener spatial diversity indices of fishing tactics (FT_SW) and strategies (YE_SW) had the greatest impact on catch rates. In particular, FT_SW was always negatively correlated to catch rates. One may anticipate that during a fishing trip, vessels with high FT_SW have been searching fish aggregations for a long time, while... |
| Tipo: Text |
Palavras-chave: Fishing effort; Fishing mortality; Catch rates; GLM modeling; Skipper effect. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/2006/publication-1339.pdf |
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| Marchal, Paul; Andersen, Bo; Caillart, B.; Eigaard, Ole; Guyader, Olivier; Hovgaard, Holger; Iriondo, Ane; Le Fur, Fanny; Sacchi, Jacques; Santurtun, Marina. |
| Face-to-face interviews were conducted to identify the main changes in gear and vessel technology that may have improved the fishing efficiency of a number of French, Danish, and Basque fleets over the past few decades. Important changes include the gradual appearance of twin trawls (Danish and French trawlers) and trammel-nets (French gillnetters), and the increased polyvalence of Basque bottom trawlers. The results suggest that fishing effort descriptors that are not traditionally measured (gear type, groundrope type, length of net used per day, headline length, crew size, number of winch or net drums) may have a substantial impact on catch rates. Adjusting fishing effort using such descriptors may generally improve the relationship between fishing... |
| Tipo: Text |
Palavras-chave: Twin trawls; Technological creep; Groundrope; Generalized linear models; Fishing mortality; Fishing effort; Catch rate. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2611.pdf |
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| Vermard, Youen; Marchal, Paul; Mahevas, Stephanie; Thebaud, Olivier. |
| The scope of this paper is to describe, evaluate, and forecast fishing trip choices of the Bay of Biscay pelagic fleet using random utility modeling (RUM). First, alternative fishing trip choices of this fleet were identified using multivariate statistical methods based on species landings weighted by value and defined as distinct fishing activity or fisheries (termed metiers). A RUM was specified, which included trip components as attributes during the period 20012004 ( a lagged percentage of the value per unit of effort of the main species caught, total value per unit of effort, and inertia in terms of changes from one metier to another). For the main metiers, the proportion of correct effort allocation is 90% during the calibration period of 2001-2004.... |
| Tipo: Text |
Palavras-chave: Management; Métier; Fishing effort; Fisher's behavior; RUM. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6096.pdf |
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| Priour, Daniel; Khaled, Ramez. |
| Trawls energy efficiency is greatly affected by the drag, as well as by the swept area. The drag results in an increase of the energy consumption and the sweeping influences the catch. Methods of optimisation of the trawl design have been developed in order to reduce the volume of carburant per kg of caught fish and consequently the drag per swept area of the trawl. Based on a finite element method model for flexible netting structures, the tool modifies step by step a reference design. For each step the best-modified design, in terms of drag per swept area is kept. Such optimisation can lead to a decrease of the drag or an increase of the swept area. In the second case, that could lead to an increase of fishing effort. To avoid such increase, which could... |
| Tipo: Text |
Palavras-chave: Fishing; Fuel; Fishing gear; Trawl; Optimisation; Fishing effort. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00170/28151/26381.pdf |
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| Peltier, Hélène; Dabin, Willy; Dars, Cécile; Demaret, Fabien; Doremus, Ghislain; Van Canneyt, Olivier; Laran, Sophie; Mendez-fernadez, Paula; Spitz, Jérôme; Authier, Matthieu; Delphine, Pierre; Ridoux, Vincent. |
| Between the 1st of February and the March 31, 2017, 793 stranded cetaceans were found along the French Atlantic coasts. Common dolphins made up 84% of these strandings, and most of these presented evidence of death in fishing gear. The aim of this work is to test an approach that could help identify the fisheries potentially involved in a given stranding event. To do this we examined how the distributions of likely areas of mortality of bycaught dolphins, inferred from carcass drift modelling, coincide with fishing effort statistics of various fleets, generated from the Vessel Monitoring System, in the area over the same dates. Using reverse drift modelling, two main mortality areas were identified. A total of 3690 common dolphins (IC95% [2230; 6900]) were... |
| Tipo: Text |
Palavras-chave: Dolphins; Strandings; Bycatch; Fishing effort; Reverse drift; Vessel Monitoring System.. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00592/70392/68473.pdf |
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| Autissier, Isabelle; Coum, Andrée; Cuillandre, Jean Pierre; Veron, Gerard; Latrouite, Daniel. |
| At the end of the seventies, as fishing abundance (based on Catch Per Unit Effort) in crabs and lobster fishery steadily declined, operating expenses increased, and fishing boats changed strategy (changing metiers, covering larger distance to fishing areas, fishing seasons being extended, ...) professionals and scientists aimed to consider reinforcing management measures. To enlighten and support potential related decisions, the Comité Régional des Pêches et Cultures Marines de Bretagne (Regional Committee for fishing and farming in Brittany), together with the ISTPM (Ifremer since 1984), conducted a survey on the exploited populations and gave a review of the involved Breton fleet. This report shows the results of a survey conducted among fishermen,... |
| Tipo: Text |
Palavras-chave: Landings; Catch rates; Fishing area; Fishing effort; Fleet; Brittany; Edible crab; Lobster; Spider crab; Apport; Rendement; Zone de pêche; Effort de pêche; Flottille; Bretagne; Tourteau; Homard; Araignée. |
| Ano: 1981 |
URL: http://archimer.ifremer.fr/doc/1981/rapport-1548.pdf |
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| Vermard, Youen; Rivot, Etienne; Mahevas, Stephanie; Marchal, Paul; Gascuel, Didier. |
| Recent advances in technologies have lead to a vast influx of data on movements, based on discrete recorded position of animals or fishing boats, opening new horizons for future analyses. However, most of the potential interest of tracking data depends on the ability to develop suitable modelling strategies to analyze trajectories from discrete recorded positions. A serious modelling challenge is to infer the evolution of the true position and the associated spatio-temporal distribution of behavioural states using discrete, error-prone and incomplete observations. In this paper, a Bayesian Hierarchical Model (HBM) using Hidden Markov Process (HMP) is proposed as a template for analyzing fishing boats trajectories based on data available from... |
| Tipo: Text |
Palavras-chave: Bayesian Hierarchical Models; Hidden Markov Model; State-space model; VMS; Fleet behaviour; Fishing effort. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00009/11993/9342.pdf |
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| Farriols, M. Teresa; Ordines, Francesc; Carbonara, Pierluigi; Casciaro, Loredana; Di Lorenzo, Manfredi; Esteban, Antonio; Follesa, Cristina; García-ruiz, Cristina; Isajlovic, Igor; Jadaud, Angelique; Ligas, Alessandro; Manfredi, Chiara; Marceta, Bojan; Peristeraki, Panagiota; Vrgoc, Nedo; Massutí, Enric. |
| The high species richness, coupled with high proportion of endemism, makes the Mediterranean one of the world’s ‘biodiversity hotspots’. However, the continuous increase in fisheries in the last few decades has led to the overexploitation of their main commercial stocks. Using fishery-independent data collected under the framework of the MEDITS trawl surveys carried out over the last 20 years, we study the demersal fish diversity pattern in the Mediterranean at a large spatial and temporal scale to determine whether it is being affected by the general fishing overexploitation of the demersal resources. The detected diversity trends are compared with the spatio-temporal variation in bottom trawl fishing effort in the Mediterranean. Our results show a... |
| Tipo: Text |
Palavras-chave: Biodiversity; Fish assemblages; MEDITS; Bottom trawling; Fishing effort; Mediterranean Sea. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00584/69628/67484.pdf |
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| Flament, Margaux; Monet, Nans; Pau, Cedric; Reynal, Lionel. |
| In the West Indies, artisanal vessels target pelagic fish off the coast using several fishing gears in the same trip, which complicates their codification based on ICCAT references. This paper describes the fishing techniques used in Martinique in exploiting offshore pelagic species. A distinction is made between two métiers, fishing for large pelagic species on free schools or around driftwood and fishing close to anchored fish aggregating devices. These two métiers can be used in the same trip. Fishers can also suspend their use to catch small offshore pelagic species such as flying fish. Each gear enables a species group to be targeted. However, data collection carried out at landing sites does not allow assignment of catches to each of the gears used... |
| Tipo: Text |
Palavras-chave: Martinique; Pelagic fisheries; Fishing gear; Fishing effort. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00418/52983/53921.pdf |
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| Registros recuperados: 74 | |
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