Study of the effect of a By-catch Reduction Panel in a twin-trawl on reducing plaice discards

Comparative fishing trials were conducted in November 2008 on the euro-cutter MFV TH-7 “Adriana Maria” on fishing grounds in the North Sea to investigate the effect of By-catch Reduction Panels inserted in a twin-trawl. In a total of 17 experimental hauls two nets were fished simultaneously, a conventional net on the starboard side and a net with a By-catch Reduction Panel inserted in the top sheet on the port side. The codend meshsize used was 80 mm. The main target species is plaice (Pleuronectes platessa L.). The By-catch Reduction Panel (BRP) tested was a square mesh panel with: 25 bars across and 22 bars deep of mesh size 150 mm, euroline™ single braid of 5 mm thickness. The panel was built in surrounding 80 mm netting and joined to 38 meshes in width and 19 meshes in depth in the port net of the twin-trawl, 12 meshes deep in front of the joining round of the codend. The panel reduced the by-catch of juvenile plaice by some 20% compared to the conventional net, but there may be a loss of marketable plaice. However, commercial losses were not confirmed by the skipper when regarding earnings over a longer period. When plaice discards are expressed as a fraction of total catch the differences were not found to be significant

Cruise report hydro acoustic survey for blue whiting (Micromesistius poutassou) with R.V. Tridens, 17 March - 04 April 2008

This is the report of the Dutch part of the international North East Atlantic hydro acoustic survey for blue whiting. The survey is coordinated by ICES and has been executed annually. The purpose of the survey is to estimate the blue whiting stock of the North East Atlantic. The ICES uses this estimation is as a “tuning index” to assess the North East Atlantic blue whiting stock. The applied method was echo integration. By sailing transects over the survey area, the total acoustic cross-section can be calculated by surface area sampled. Trawling identified species composition of localized schools. The length composition of each species was determined. Blue whiting was examined on age and fecundity from which a split up stock structure was mad

Reisverslag BTS 2013

In 2013, the beam trawl survey (BTS) was carried out by Tridens II and Isis. The survey is part of the EU Data Collection Framework (DCF). This report describes the results and contains the cruise reports of the trips. The results for sole and plaice in the BTS are used by the ICES assessment working group. Furthermore, the BTS data are used for research concerning the North Sea ecosystem. In 2013 representatives of the fisheries sector were on board of RV Tridens as observers. The observers reported in Visserijnieuws

Baseline studie vis MVII: veldwerkrapportage najaar 2007

In het kader van de aanleg van de Tweede Maasvlakte is besloten om in de Voordelta een zeereservaat in te stellen met een grootte van circa 30.000 hectare. Dit zeereservaat zou de gevolgen van de landaanwinning van ongeveer 3000 hectare moeten compenseren. In het kader van een tweede nulmeting juveniele vis in het gebied waar de Tweede Maasvlakte zal worden aangelegd, wordt in voor- en najaar 2007 op een vijftigtal lokaties gevist met een garnalenkor. Dit rapport bevat de veldwerkrapportage van het onderzoek dat door IMARES in opdracht van RIKZ is uitgevoerd in de periode 20 augustus t/m 7 september 2007

Industrial survey for associated species: Results of a pilot-year

To increase scientific knowledge and stimulate discussion on management of data-limited species, Ekofish Group B.V., the North Sea Foundation (NSF) and IMARES started a research project. This project consisted of two phases. In the first phase, IMARES and NSF performed a literature study on the constrains in management and biological knowledge for species selected by Ekofish. After phase one, Ekofish Group B.V. requested IMARES to set up an industrial survey to gather more information on turbot, brill and lemon sole. A pilot-survey was designed and performed for these species to test whether an industrial survey is feasible and valuable for biological knowledge and if so, how this survey should be designed. To test the design of the survey, research will be done on the haul duration and mesh size. To examine the added value of the pilot survey, results are compared with the BTS. In this report, the results of this pilot survey are presented and answer will be given to the following research question: “Is an industrial survey for turbot, bill and lemon sole feasible and does it increase knowledge with respect to scientific surveys?

The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape : A Large-Scale Genome-Wide Interaction Study

Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially between men and women. To systematically screen for age-and/or sex-specific effects of genetic variants on BMI and WHRadjBMI, we performed meta-analyses of 114 studies (up to 320,485 individuals of European descent) with genome-wide chip and/or Metabochip data by the Genetic Investigation of Anthropometric Traits (GIANT) Consortium. Each study tested the association of up to similar to 2.8M SNPs with BMI and WHRadjBMI in four strata (men 50y, women 50y) and summary statistics were combined in stratum-specific meta-analyses. We then screened for variants that showed age-specific effects (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR= 50y). No sex-dependent effects were identified for BMI. For WHRadjBMI, we identified 44 loci (27 previously established for main effects, 17 novel) with sex-specific effects, of which 28 showed larger effects in women than in men, five showed larger effects in men than in women, and 11 showed opposite effects between sexes. No age-dependent effects were identified for WHRadjBMI. This is the first genome-wide interaction meta-analysis to report convincing evidence of age-dependent genetic effects on BMI. In addition, we confirm the sex-specificity of genetic effects on WHRadjBMI. These results may providefurther insights into the biology that underlies weight change with age or the sexually dimorphism of body shape.Peer reviewe

Study of the effect of a By-catch Reduction Panel in a twin-trawl on reducing plaice discards

Comparative fishing trials were conducted in November 2008 on the euro-cutter MFV TH-7 “Adriana Maria” on fishing grounds in the North Sea to investigate the effect of By-catch Reduction Panels inserted in a twin-trawl. In a total of 17 experimental hauls two nets were fished simultaneously, a conventional net on the starboard side and a net with a By-catch Reduction Panel inserted in the top sheet on the port side. The codend meshsize used was 80 mm. The main target species is plaice (Pleuronectes platessa L.). The By-catch Reduction Panel (BRP) tested was a square mesh panel with: 25 bars across and 22 bars deep of mesh size 150 mm, euroline™ single braid of 5 mm thickness. The panel was built in surrounding 80 mm netting and joined to 38 meshes in width and 19 meshes in depth in the port net of the twin-trawl, 12 meshes deep in front of the joining round of the codend. The panel reduced the by-catch of juvenile plaice by some 20% compared to the conventional net, but there may be a loss of marketable plaice. However, commercial losses were not confirmed by the skipper when regarding earnings over a longer period. When plaice discards are expressed as a fraction of total catch the differences were not found to be significant

Reisverslag BTS 2013

In 2013, the beam trawl survey (BTS) was carried out by Tridens II and Isis. The survey is part of the EU Data Collection Framework (DCF). This report describes the results and contains the cruise reports of the trips. The results for sole and plaice in the BTS are used by the ICES assessment working group. Furthermore, the BTS data are used for research concerning the North Sea ecosystem. In 2013 representatives of the fisheries sector were on board of RV Tridens as observers. The observers reported in Visserijnieuws