Documents | Seafish

A Comparison of One Tenth and Full Scale Measurements of the Drag and Geometry of a Pelagic Trawl

Current practices in modeling fishing gear have been investigated by comparing the shape and drag of a nylon pelagic trawl at one tenth scale with those of its full scale equivalents. The work has concluded that accurate modeling must take into account rope and twine elongation particularly in nylon nets and the change of drag coefficient with Reynolds Number and Froude Number is held constant. This report has been produced from a scanned original and may therefore contain some formatting and other inaccuracies. In cases where this affects the technical content, a paper copy of the original report can still be obtained from Seafish.

A Report to the Fish Industry Forum on The Marine Stewardship Council and Related Topics

The work reported here was instigated by the Fish Forum at its meeting in July 1998. The terms of reference were: ‘ . . to produce a paper . . to cover the ownership, independence and functions of the MSC, a discussion of the demand for and problems associated with eco-labelling, and a commentary on the Nordic Council Proposal made at a recent meeting in Bremen.’

Statement to the Press: MarinTrust accepts North East Atlantic Blue Whiting FIP onto Improver Programme

A North Atlantic Pelagic Advocacy (NAPA) Group press statement.

Open letter to Ministers - pre-quota allocation meetings

The North Atlantic Pelagic Advocacy (NAPA) Group shares an open letter urging Ministers to work constructively to prioritise resolving allocation issues to ensure the overall catch for each stock does not overstep the scientific advice.

Towing Requirements for a Pair Trawl (2 x 340hp Vessels)

This report contains the performance data of a FMA Buckie Pair Trawl - BT 154, rigged with 2 bridles and rockhopper gear. It expresses the power requirements in terms of warp tensions and settings of net speed, warp length and vessel distance and defines the best settings for fuel consumption. This report has been produced from a scanned original and may therefore contain some formatting and other inaccuracies. In cases where this affects the technical content, a paper copy of the original report can still be obtained from Seafish

Time Series for interpreting events in the sea

Time series are scientific measurements taken over sufficiently long periods of time. They permit the detection of rare of episodic events which would not have been apparent if collected over one year. The marine ecosystem gives good results from time series because there is a better coupling between signal and response than is normally found in land systems.

Highland Region - The Creel Fisheries of Caithness & Sutherland Prospects for Development 1991-99

The study has examined the creel fisheries for brown crab, velvet crab and lobster along the coasts of Caithness and Sutherland. By implication it has been necessary to include Nephrops as these are an important source of income to local creel fishermen.

Verification Trials of an Oyster Purification Tank for Mr JW Gardner

Keywords: purification, pacific oysters

Technical Assessment of Multiple Bodied Trawl Development Project

The Highlands and Islands Enterprise Network approached the Sea Fish Industry Authority to provide a technical assessment for a grant application they had received. A small net manufacturer based in Thurso applied to develop a new type of multiple bodied trawl which was considered (theoretically) to be more efficient at catching certain species by increasing the total net area without the corresponding increase in resistance. They propose to design, construct and test a model in a flume tank before going on to construcing a full scale trawl for trails on a commercial vessel. The objectives of the assessment were to give an independent and impartial appraisal.

Flume Tank Testing of 1:4 scale model trawl doors

This report describes a test procedure to obtain accurate performance curves of model trawl doors in a Flume Tank. The purpose is to establish a consistent method of predicting door performance in order that fishermen and others can be advised of the best size and design of door for a particular net. The performance of a single model trawl door is assessed by measuring the tensions and angles of the warp and bridle which retain the door in a fixed position in the tank. Two coefficients are derived : CL representing lift or spreading force and CD representing the drag force. CL/CD represents a measure of efficiency of the door. The Flume Tank equipment required to measure the necessary parameters is described along with the experimental procedures. Results are given for standard flat and vee doors over a range of angles of attack and heel. This data in the form of CLand CD is used as a base against which to compare the performance of other door types. This report has been produced from a scanned original and may therefore contain some formatting and other inaccuracies. In cases where this affects the technical content, a paper copy of the original report can still be obtained from Seafish.

BP Exploration Fishing Activities in Way of Forties Pipeline Route

The pipeline route passes through four ICES 'statistical rectanle' areas. Each statistical rectangle comprises an area bounded by one degree of longitude and one half degree of latitude. The rectangles are defined by Sea Area (IVa is the Northern North Sea and IVb is the Central North Sea) together with a number for each individual rectangle. The dividing line between Northern and Central North Sea Areas lies at latitude 57 <sup>o</sup> 30'N and is crossed by the pipeline.

Selectivity in Trawls Selection Devices aimed at the release of juvenile cod

Seafish have a continuing programme to improve selectivity in towed gear and considerable advances have been made in reducing discards of haddock and whiting from trawls through the use of square mesh panels inserted into the upper part of the extension. There has not so far been any similar reduction in cod discards.

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