scholarly journals Segmentation and fishery characteristics of the mixed-species multi-gear Portuguese fleet

2009 ◽  
Vol 66 (3) ◽  
pp. 594-606 ◽  
Author(s):  
Rafael Duarte ◽  
Manuela Azevedo ◽  
Manuel Afonso-Dias
Keyword(s):  
Cluster Analysis ◽  
Multivariate Regression ◽  
Geographic Location ◽  
Regression Trees ◽  
Hierarchical Cluster ◽  
Single Species ◽  
Mixed Species ◽  
Important Species ◽  
Multivariate Regression Trees ◽  
The North

Abstract Duarte, R., Azevedo, M., and Afonso-Dias, M. 2009. Segmentation and fishery characteristics of the mixed-species multi-gear Portuguese fleet. – ICES Journal of Marine Science, 66: 594–606. Fleet segmentation and knowledge of fishing fleet dynamics are essential to move from single species to fishery/fleet-based advice. The coastal mixed-species multi-gear Portuguese fleet comprises medium-sized (>12 m) vessels, using a diversity of passive gears, and is economically important. For hake (under a recovery plan) and monkfish (overexploited), it contributes >50% to their total annual landings. Commercial daily landings in 2005 from 271 vessels were analysed by region using non-hierarchical cluster analysis and multivariate regression trees. The cluster analysis allowed the identification of regional fleet segments with a low mixture of species throughout the year. The multivariate regression trees were applied to clusters of vessels with a high mixture of species, to explain weekly landing profiles (species) by vessel technical characteristics, fishing license, and main landing port. The results showed a link between exploited species and geographic location, and in the north between vessel size and depth and an inshore/offshore range. Finally, from the analysis and for the most important species exploited by the Portuguese multi-gear fleet, it was possible to define two or three vessel groups that accounted for at least 50% of the landed value.

Auto-associative Multivariate Regression Trees for Cluster Analysis

2006 ◽  
Vol 80 (1) ◽  
pp. 120-129 ◽  
Author(s):  
Christine Smyth ◽  
Danny Coomans ◽  
Yvette Everingham ◽  
Timothy Hancock
Keyword(s):  
Cluster Analysis ◽  
Multivariate Regression ◽  
Regression Trees ◽  
Multivariate Regression Trees

From single-species advice to mixed-species management: taking the next step

2004 ◽  
Vol 61 (8) ◽  
pp. 1398-1409 ◽  
Author(s):  
Morten Vinther ◽  
Stuart A. Reeves ◽  
Kenneth R. Patterson
Keyword(s):  
North Sea ◽  
Fishery Management ◽  
Single Species ◽  
Mixed Species ◽  
The North ◽  
Recent Approach ◽  
Starting Point ◽  
The North Sea ◽  
Management Advice ◽  
Management Priorities

Abstract Fishery management advice has traditionally been given on a stock-by-stock basis. Recent problems in implementing this advice, particularly for the demersal fisheries of the North Sea, have highlighted the limitations of the approach. In the long term, it would be desirable to give advice that accounts for mixed-fishery effects, but in the short term there is a need for approaches to resolve the conflicting management advice for different species within the same fishery, and to generate catch or effort advice that accounts for the mixed-species nature of the fishery. This paper documents a recent approach used to address these problems. The approach takes the single-species advice for each species in the fishery as a starting point, then attempts to resolve it into consistent catch or effort advice using fleet-disaggregated catch forecasts in combination with explicitly stated management priorities for each stock. Results are presented for the groundfish fisheries of the North Sea, and these show that the development of such approaches will also require development of the ways in which catch data are collected and compiled.

scholarly journals Discrimination of Thymus, Origanum, Satureja and Thymbra species from the family Labiatae by untargeted metabolomic analysis

2020 ◽  
Vol 38 (No. 3) ◽  
pp. 151-157
Author(s):  
Nurcan Ayşar Güzelsoy ◽  
Filiz Çavuş ◽  
Oya Kaçar
Keyword(s):  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Hierarchical Cluster Analysis ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Single Species ◽  
Metabolomic Analysis ◽  
Methanolic Extracts ◽  
The Family ◽  
Extraction Algorithm

The term “thyme” does not refer to herbs that belong to a single species. The genera Thymus, Origanum, Satureja and Thymbra of the family Labiatae are traditionally named as thyme and locally known as ‘kekik’. Unlike Turkey, these species are globally called differently. Spices made of Origanum, Thymus and Satureja are called oregano, thyme and savory, respectively. It is often difficult to differentiate them because of their similar smell and appearance. Most commercial products traded as a mixture of those genera and the mixing together of different species may lead to economically motivated adulteration and a product of reduced value. The species were analysed by LC-ESI-QTOF-MS and a comprehensive statistical workflow was designed. The data of methanolic extracts were assessed and an extraction algorithm was employed for the processing of raw data. Five species were discriminated using principal component analysis (PCA) and hierarchical cluster analysis (HCA). The results of PCA and HCA were consistent with each other. Twenty-one metabolites were determined for the discrimination.

Host-correlated morphological variation of Myzus persicae (Hemiptera: Aphididae) populations in Greece

2000 ◽  
Vol 90 (3) ◽  
pp. 233-244 ◽  
Author(s):  
J.T. Margaritopoulos ◽  
J.A. Tsitsipis ◽  
E. Zintzaras ◽  
R.L. Blackman
Keyword(s):  
Cluster Analysis ◽  
Host Plant ◽  
Morphological Variation ◽  
Myzus Persicae ◽  
Prunus Persica ◽  
Classification Tree ◽  
Hierarchical Cluster ◽  
Canonical Variate ◽  
Primary Host ◽  
The North

Morphological variation in nine characters of 157 clones of Myzus persicae(Sulzer) was examined by multivariate analysis. The clones were collected from peach, Prunus persica, the primary host and the secondary hosts tobacco, Nicotiana tabacum, cabbage, Brassica oleracea, sugarbeet, Beta vulgaris and pepper Capsicum annuum. The 156 clones originated from various regions of Greece, both in the north, where a large part of the population has an annual bisexual generation on peach, and in more southerly regions, where populations are predominantly unisexual. One clone was collected from tobacco in Caserta, Italy. All clones were laboratory-reared on potato. Canonical variate analysis, hierarchical cluster analysis and a non-parametric classification tree method both revealed morphological differences associated with the host-plant on which they were collected. The scores of the first two canonical variates separated the tobacco-feeding clones from those originating from other secondary host-plants. However, in tobacco-growing areas the tobacco-feeding form predominated in spring populations on peach, and was sometimes found on other secondary hosts. In addition, using cluster analysis, the clones from tobacco which were sampled in the most southeasterly region showed a relatively large phenotypic distance from those collected further north and west. Moreover, clonal phenotypes were affected both by host plant and by long-term parthenogenetic rearing. However, in spite of these effects, the tobacco form was generally distinguishable from aphids originating from other hosts, indicating that the difference must have a genetic basis. In separate analyses of the clones originating from secondary hosts no association was found between morphology and either life cycle category or colour. Discriminant analysis showed that 89% of 1723 specimens could be correctly classified into the two groups.

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