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| Trenkel, Verena; Rochet, Marie-joelle; Sari, Tewfik. |
| There exists an urgent need in fisheries science for simple models for assessing the impact of fishing on the dynamics of fish communities. We present a new class of predator prey models that describe the relationship between predators and their prey by piecewise-linear differential equations. Interactions are governed by threshold values for population abundances. The simplest model has four distinct cases with different asymptotic stable states. The model allows for fishing mortality on both predator and prey. If fishing mortality on either the predator, the prey or both are varied, the system might move to new stable states. The threshold values act as reference points for fishing exploitation, as they indicate a structural change in the predator-prey... |
| Tipo: Text |
Palavras-chave: Predator-prey model; Reference points; Differential equations. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00453/56511/58207.pdf |
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| 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 |
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| Ravard, David; Brind'Amour, Anik; Trenkel, Verena. |
| Fishing affects fish populations through direct and indirect effects. It can change size structures and/or modify population mean weights. Reference values are thus needed to assess the status of populations in exploited ecosystems. These reference values can either be set by a historical approach, i.e. using information from before the onset of exploitation or overexploitation, or by a simulation approach. Using a model based on life-history parameters, we predicted population mean weights and length structures at equilibrium (in the absence of fishing and for fishing equal to different fishing mortalities) which we compared with contemporary data collected during scientific surveys in the Bay of Biscay. Contemporary mean weights were 88% to 30% smaller... |
| Tipo: Text |
Palavras-chave: Indicators; Fishing impacts; Ecosystem based management; Fish community; Reference points; Northeast Atlantic. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00188/29968/28485.pdf |
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| Kacar,Dundar; Cakmak,Fethiye; Dogan,Ash; Sevinc,Ozdemir; Barut,Cagatay. |
| A fold of tissue, the lingual frenulum, extends onto the inferior surface of the tongue from near the base of the tongue on midline. The shape, length and alignment of lingual frenulum vary between individuals. The aim of this study is to evaluate morphology of lingual frenulum with respect to gender. Ninety seven volunteers who were students and employees of Zonguldak Karaelmas University, School of Medicine participated in the study. Two individuals with a history of hepatitis and 20 individuals with inadequate photographs were excluded from the study. Morphometric analyses were performed on the photographs of 75 volunteers (36 men, 39 women). Lingual frenulum photograph of each individual was taken using standard photographic techniques. The individual... |
| Tipo: Journal article |
Palavras-chave: Lingual frenulum; Geometric morphometrics; Men; Women; Reference points. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-95022011000200001 |
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| Rindorf, Anna; Dichmont, Catherine M.; Thorson, James; Charles, Anthony; Clausen, Lotte Worsoe; Degnbol, Poul; Garcia, Dorleta; Hintzen, Niels T.; Kempf, Alexander; Levin, Phillip; Mace, Pamela; Maravelias, Christos; Minto, Coilin; Mumford, John; Pascoe, Sean; Prellezo, Raul; Punt, Andre E.; Reid, David G.; Roeckmann, Christine; Stephenson, Robert L.; Thebaud, Olivier; Tserpes, George; Voss, Ruediger. |
| Targets and limits for long-term management are used in fisheries advice to operationalize the way management reflects societal priorities on ecological, economic, social and institutional aspects. This study reflects on the available published literature as well as new research presented at the international ICES/Myfish symposium on targets and limits for long term fisheries management. We examine the inclusion of ecological, economic, social and institutional objectives in fisheries management, with the aim of progressing towards including all four objectives when setting management targets or limits, or both, for multispecies fisheries. The topics covered include ecological, economic, social and governance objectives in fisheries management, consistent... |
| Tipo: Text |
Palavras-chave: Ecosystem-based fisheries management; Multiple objectives; Reference points; Sustainability; Variability. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00381/49262/49838.pdf |
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