|
|
|
| Registros recuperados: 129 | |
|
|
| Fromentin, Jean-marc. |
| In 2002, about 40% of the yield of the French purse seine fleet targeting bluefin tuna came from the Gulf of Lions, 38% from the Balearic Islands and about 22% from the Malta-Lybia area (a new area for this fleet). The fleet caught, in the Gulf of Lions, mostly juvenile bluefin (mainly 2 and 3 years old), whereas both juveniles and adults were targeted and caught in the Balearic and Maltese areas. As in 2001, the 2002 size composition of bluefin catches have been estimated from the EU log-books and both years looked very similar. Calculating Kolmogorov-Smirnov two sample tests between the yearly size compositions of 1990-1995 and those of 2001 and 2002, indicated significant differences between these two pools of data. Finally, we confirm that if the... |
| Tipo: Text |
Palavras-chave: Atlantic bluefin tuna; Catch statistics. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00194/30482/28889.pdf |
| |
|
| |
|
| |
|
| |
|
|
| Royer, Francois; Fromentin, Jean-marc; Gaspar, P. |
| Archival tagging provides a unique way to study the spatial dynamics and habitat of pelagic fish. This technique generates lagrangian data of a particular type in marine ecology: although highly informative about processes at different scales (e.g. horizontal movements versus diving behaviour), such data are impaired by location errors and the lack of combination with actual environmental variability. The present paper introduces a framework for modelling bluefin tuna movement in relation to its habitat, using records of light, depth and temperature from archival tags. Based on data assimilation concepts and methods, we show how an explicit formulation of the observation process and the statistics of external variables (e.g. ambient temperature) can... |
| Tipo: Text |
Palavras-chave: Tag; Archival; Habitat; Movement; Bluefin tuna. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-671.pdf |
| |
|
|
| Brosset, Pablo; Lloret, Josep; Munoz, Marta; Fauvel, Christian; Van Beveren, Elisabeth; Marques, Virginie; Fromentin, Jean-marc; Menard, Frederic; Saraux, Claire. |
| Limited resources in the environment prevent individuals from simultaneously maximizing all life-history traits, resulting in trade-offs. In particular, the cost of reproduction is well known to negatively affect energy investment in growth and maintenance. Here, we investigated these trade-offs during contrasting periods of high versus low fish size and body condition (before/after 2008) in the Gulf of Lions. Female reproductive allocation and performance in anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) were examined based on morphometric historical data from the 1970s and from 2003 to 2015. Additionally, potential maternal effects on egg quantity and quality were examined in 2014/2015. After 2008, the gonadosomatic index increased for... |
| Tipo: Text |
Palavras-chave: Maternal effect; Northwest Mediterranean; Anchovy; Sardine. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00353/46458/46233.pdf |
| |
|
|
| Cury, Philippe M.; Fromentin, Jean-marc; Figuet, Sarah; Bonhommeau, Sylvain. |
| The relationship between spawning fish abundance and the number of offspring, the so-called stock-recruitment relationship, is crucial for fisheries management and conservation measures. Using the most comprehensive data set ever assembled, we quantify this relationship for 211 fish stocks worldwide, revealing a global pattern with a pervasive asymptotic shape that shows increasing recruitment reaching an upper limit for values around half to two-thirds of parental biomass. This corroborates previous theoretical and modeling results. However, parental biomass is a predictor for only 5% to 15% of the variance in recruitment, demonstrating the weak predictive power of the stock-recruitment relationship in marine fish populations. Thus, there is a need to... |
| Tipo: Text |
|
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00253/36441/35000.pdf |
| |
|
| |
|
|
| Brosset, Pablo; Fromentin, Jean-marc; Menard, Frederic; Pernet, Fabrice; Bourdeix, Jean-herve; Bigot, Jean-louis; Van Beveren, Elisabeth; Perez Rodia, Maria A.; Choy, Sandrine; Saraux, Claire. |
| As condition is a key variable in population dynamics (especially for survival, growth and reproduction), the use of well-defined and accurate fish condition indices is capital. In particular, condition indices (morphometric, bioenergetic and biochemical) have never been compared and validated for the European anchovy Engraulis encrasicolus, the European pilchard Sardina pilchardus and the European sprat Sprattus sprattus. The accuracy of two indirect methods, the morphometric relative condition index Kn and the bioenergetics index determined with the Distell Fish Fatmeter was investigated by comparing with a direct measure of relative lipid content carried out with a thin layer chromatography-flame ionization detector. Estimations from the fatmeter... |
| Tipo: Text |
Palavras-chave: Anchovy; Fatmeter; Lipids; Mediterranean Sea; Sardine; Sprat. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00226/33741/32304.pdf |
| |
|
|
| Simon, Maximilien; Fromentin, Jean-marc; Bonhommeau, Sylvain; Gaertner, Daniel; Brodziak, Jon; Etienne, Marie-pierre. |
| The intrinsic population growth rate (r) of the surplus production function used in the biomass dynamic model and the steepness (h) of the stock-recruitment relationship used in age-structured population dynamics models are two key parameters in fish stock assessment. There is generally insufficient information in the data to estimate these parameters that thus have to be constrained. We developed methods to directly estimate the probability distributions of r and h for the Atlantic bluefin tuna (Thunnus thynnus, Scombridae), using all available biological and ecological information. We examined the existing literature to define appropriate probability distributions of key life history parameters associated with intrinsic growth rate and steepness, paying... |
| Tipo: Text |
|
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00115/22640/20362.pdf |
| |
|
|
| Kell, Laurence T; Fromentin, Jean-marc; Gauthiez, F; Restrepo, Victor. |
| The Ad Hoc Working Group on the Precautionary Approach (SCRS/99/11) recommended the development of a simulation modelling framework to investigate the performance of stock specific management strategies under a variety of realistic hypothesis about population and fishery dynamics. This paper describes a preliminary simulation model based on East Atlantic bluefin tuna developed using flexible software that allows the implications for management of a variety of plausible hypotheses about stock and fishery dynamics to be explored. The intention is to illustrate the ways in which such models can be used and the types of advice that they can provide |
| Tipo: Text |
|
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00194/30566/28991.pdf |
| |
|
|
| Kell, Laurence T; Fromentin, Jean-marc. |
| Reference points are important elements of fisheries management and the supporting scientific advisory frameworks. However, fish stocks can fluctuate extensively over a large range of spatial and temporal scales independent of human exploitation and there has been a classical tendency to assume a dichotomy, i.e., that changes in fish populations are primarily attributable either to exploitation or to environmental variability. Therefore we look at variability in surplus production and examine the relative impacts of the environment and exploitation on the productivity of North Atlantic albacore (Thunnus alalunga). The analysis revealed that variations were driven by environmental effects. It was also found that substantial variations in time-series of... |
| Tipo: Text |
Palavras-chave: Thunnus alalunga; Albacore; Fisheries management; FLR; Reference points; Stationary processes; Surplus production.. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30282/28758.pdf |
| |
|
|
| Pons, Maite; Branch, Trevor A.; Melnychuk, Michael C.; Jensen, Olaf P.; Brodziak, Jon; Fromentin, Jean-marc; Harley, Shelton J.; Haynie, Alan C.; Kell, Laurie T.; Maunder, Mark N.; Parma, Ana M.; Restrepo, Victor R.; Sharma, Rishi; Ahrens, Robert; Hilborn, Ray. |
| Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life-history characteristics and economic incentives, but differences in exploitation histories and management measures also have a strong effect on current stock status. Although the status (biomass and fishing mortality rate) of major tuna and billfish stocks is well documented, the effect of these diverse factors on current stock status and the effect of management measures in rebuilding stocks have not been analysed at the global level.... |
| Tipo: Text |
Palavras-chave: Fisheries management; Marine conservation; Stock assessment; Stock status; Tuna fisheries. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00333/44383/44107.pdf |
| |
|
|
| Rodríguez‐ezpeleta, Naiara; Díaz‐arce, Natalia; Walter, John F; Richardson, David E; Rooker, Jay R; Nøttestad, Leif; Hanke, Alex R; Franks, James S; Deguara, Simeon; Lauretta, Matthew V; Addis, Piero; Varela, Jose Luis; Fraile, Igaratza; Goñi, Nicolas; Abid, Noureddine; Alemany, Francisco; Oray, Isik K; Quattro, Joseph M; Sow, Fambaye N; Itoh, Tomoyuki; Karakulak, F Saadet; Pascual‐alayón, Pedro J; Santos, Miguel N; Tsukahara, Yohei; Lutcavage, Molly; Fromentin, Jean-marc; Arrizabalaga, Haritz. |
| Effective sustainable management of marine fisheries requires that assessed management units (that is, fish stocks) correspond to biological populations. This issue has long been discussed in the context of Atlantic bluefin tuna (ABFT, Thunnus thynnus) management, which currently considers two unmixed stocks but does not take into account how individuals born in each of the two main spawning grounds (Gulf of Mexico and Mediterranean Sea) mix in feeding aggregations throughout the Atlantic Ocean. Using thousands of genome‐wide molecular markers obtained from larvae and young of the year collected at the species’ main spawning grounds, we provide what is, to the best of our knowledge, the first direct genetic evidence for “natal homing” in ABFT. This has... |
| Tipo: Text |
|
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00595/70710/68917.pdf |
| |
|
|
| Fromentin, Jean-marc. |
| The 2001 size composition of Atlantic bluefin tuna catches of the French purse seiners has been estimated from the EU log-books and appears roughly in agreement with those estimated from the local seafood traders between 1982 and 1998. However, the accuracy of the 2001 size composition remains uncertain because of a lack of a standard protocol and of sampling on catch coming from heterogeneous and/or multiple shoals. Regarding the spatial and temporal dynamic of the French fishery, an observer program should be implemented to correct and validate the size frequencies of these catches. |
| Tipo: Text |
|
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00194/30526/28938.pdf |
| |
|
| |
|
|
| Bonhommeau, Sylvain; Fromentin, Jean-marc. |
| This study aims at examining the potential bias in the VPA estimates by simulating a population, catch and CPUEs over 39 years from 1970 to 2008. In the operational model, two levels of noise were added to catch and CPUEs (50 and 100%), three fishing patterns were explored (F=FMSY, F increases linearly from 0.5 FMSY to 2.5 FMSY, F increases linearly from 0.5 FMSY to 2.5 FMSY over the first 34 years and decreases down to FMSY over the last 5 years). We also tested different hypothesis about the impact of the terminal F-ratios, and the natural mortality used in the current VPA as well as the impact of randomly generated CPUE for long-line and trap CPUE. Results show that the VPA is robust to estimate the SSB whatever the noise level in the catch and the... |
| Tipo: Text |
Palavras-chave: Bluefin tuna; Stock assessment; VPA; Management regulations; TAC. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00192/30280/28755.pdf |
| |
|
| |
|
|
| Brosset, Pablo; Menard, Frederic; Fromentin, Jean-marc; Bonhommeau, Sylvain; Ulses, Caroline; Bourdeix, Jean-herve; Bigot, Jean-louis; Van Beveren, Elisabeth; Roos, David; Saraux, Claire. |
| Endogenous and environmental variables are fundamental in explaining variations in fish condition. Based on more than 20 yr of fish weight and length data, relative condition indices were computed for anchovy and sardine caught in the Gulf of Lions. Classification and regression trees (CART) were used to identify endogenous factors affecting fish condition, and to group years of similar condition. Both species showed a similar annual cycle with condition being minimal in February and maximal in July. CART identified 3 groups of years where the fish populations generally showed poor, average and good condition and within which condition differed between age classes but not according to sex. In particular, during the period of poor condition (mostly recent... |
| Tipo: Text |
Palavras-chave: Anchovy; Sardine; Relative condition factor; NW Mediterranean Sea; Endogenous effect; Environmental effect. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00272/38334/36575.pdf |
| |
|
| |
| Registros recuperados: 129 | |
|
|
|
