Landings and discards on the pulse trawl MFV "Vertrouwen"TX68 in 2009

The catches in terms of landings and discards were monitored onboard MFV “Vertrouwen” TX68, fishing with two pulse trawls using the Verburg-Holland system during four weeks in June-August 2009. The average fishing speed was about 5 knots. The fishing area of the four trips was east of the coast of England and fishing depth was 36m on average with a minimum depth of 20 m and a maximum depth of 46 m. For this study the standard sampling procedure for the yearly monitoring of discards of conventional beam trawl fleet was applied (van Helmond and van Overzee, 2008). Sampled numbers of fish per haul were raised to numbers and weight per hour, for both. When compared with conventional beam trawls in previous years it seems that with the pulse trawl more sole in number and weights per unit of time was discarded and less plaice was discarded. However, the average discard percentages of as well plaice as sole for the pulse trawl of this study were within range with the average discard percentages of conventional beam trawls in 2005, 2006 and 2007 (van Keeken, 2006; van Helmond and van Overzee, 2007; van Helmond and van Overzee, 2008) . This study gives a general impression of the performance in terms of catches of fishing with a pulse trawl using the Verburg-Holland system. However it is recommended to conduct a comparative study on performance of a beam trawl and a pulse trawl, where the two vessels of similar size fish simultaneously, like was done in 2006 by van Marlen et al. This is to exclude the effects of time and area of fishing

Energy Saving in Fisheries (ESIF) FISH/2006/17 LOT3: final report

Project “Energy Saving in Fisheries” (ESIF) aimed at investigating potential technical and operational methods to address the need to reduce energy consumption and associated costs in European fisheries. The study started with an inventory of potential technical solutions and ongoing projects in the participating member states. The economic performance of selected fleet segments was analysed with emphasis on the role of energy costs. This economic analysis considered aspects such as: break-even fuel price, factors determining energy efficiency, the economic potential for technological improvement and scenarios for future outlook related to possible develop-ment of fuel price. Finally, the economic feasibility of proposed technological adaptations was assesse

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

The effect of pulse stimulation on marine biota - Research in relation to ICES advice - Progress report on the effects on benthic invertebrates

In response to ecosystem related concerns about bottom trawling and particularly beam trawling that were raised by various scientists in the last decades of the previous century. Many studies were done in the 1970s and 1980s, but in spite of promising results commercial uptake was lacking. The development of pulse trawling was again taken up in the 1990s by a private company (Verburg:Holland Ltd.) in The Netherlands. Meanwhile questions about ecosystem effects of introducing pulse beam trawling in the Dutch flatfish fishery were raised by the European Scientific, Technical and Economic Committee for Fisheries (STECF) and the Inter: national Council for the Exploration of the Sea (ICES) and discussed at the meeting of the ICES Working Group on Fishing Technology and Fish Behaviour (WGFTFB) in 2006. These questions led to field strength measurements in situ onboard the commercial beam trawler, and research on the effects of pulse stimulation on cod (Gadus morhua L.), and elasmobranch fish

The effects of pulse stimulation on biota - Research in relation to ICES advice - Effects on dogfish

Onderzoek naar het welzijn van hondshaaien bij de vangst. Er is onderzocht of de methode van het gebruik van stroom wel diervriendelijk is. De conclusie is dat dit geen beletsel voor de diervriendelijkheid oplever

Toezicht op minimum maaswijdte

De vangst en sterfte van vis wordt hoofdzakelijk bepaald door de maaswijdte (of maasopening) in de kuil van het gebruikte visnet. Meting van maaswijdte is niet eenvoudig en de huidige regelgeving is aan kritiek onderhevig. Dit heeft geleid tot de ontwikkeling van een nieuw meetprotocol en meetinstrument. De visserij op tong met 80 mm en een minimummaat van 24 cm is gevoelig voor een juiste vaststelling van de maaswijdte van de kuil. Dit rapport behandelt statistische en juridische aspecten van de huidige regelgeving en de eventuele invoering van de nieuwe OMEGA-maaswijdtemeter

Reduction of discards by technical modifications of beam trawls

Experiments were carried out in 2007 and 2008 on discard reducing techniques in flatfish beam trawling onboard FRV “Tridens” in close cooperation with the fishing industry. A total of 38 gear tests were conducted in which modified beam trawls were compared in pair with a conventional 12 m beam trawl. The modifications consisted of a T90 aft part and various Square Mesh Panels (SMPs) in the bottom sheet, top sheet and combinations of both, and variations of a Benthos Release Hole with a guiding V-panel in the bottom sheet. It was found that a panel in the bottom sheet with 160 mm mesh size appeared to perform best without releasing too many marketable fish. The panel should extend relatively far aft just in front of the codend here the netting is offground. Panels placed only in the top sheet are not very suitable in reducing benthos ycatches. In addition the Benthos Release Hole with guiding device seems to be effective in reducing such bycatches. The cooperation between fishermen and scientists worked very well and created better mutual understanding. Further work is advocated to optimise the design of these devices. It is expected that such devices will get wider application in the Dutch beam trawling sector

Onderzoek naar de verbetering van tongvangsten in de outrigvisserij

De laatste jaren is de boomkorvisserij onder druk komen te staan vanwege de effecten van deze methode van vissen op het mariene ecosysteem. De recente stijging van gasolieprijzen en daarmee samenhangende brandstofkosten van rond de 0.20 €/ltr tot ca. 0.70 €/ltr brengen de rendabiliteit van deze visserijsector in gevaar. Er wordt dan ook betwijfelt of de huidige boomkorvisserij nog toekomst heeft . Om deze redenen zoeken vissers naar alternatieve vangstmethoden, zoals de ‘outrig’ visserij. Deze methode, waarbij met een bordentrawl vanuit de gieken van een boomkorschip wordt gevist levert een aanzienlijke brandstofbesparing op, maar de vangst van tong is doorgaans minder door geringer bodemcontact