Explanatory Notes

       This volume is a result of the surveys on marine fishing gear and methods in Vietnam from January 1997 to December 1999. The survey locations are selected from provinces where fisheries developed and are shown in Figure 1 . The abbreviations and symbols used in illustrations and the surveys are in accordance with the use as in the first, second and third volumes ( Thailand , Malaysia and Philippines ). The number of surveyed fishing gear types is shown in Table 6 . The data, which are introduced in this monograph, were based on the data contained in reports of Vietnamese Ministry of Fisheries and the data from practical surveys conducted by the Research Institute of Marine Products.

llustrations :

     1) Drawing of the horizontal length of surrounding nets, seine net and gill net depends on the length of the float line, and the vertical depth depends on the vertical hanging ratio of netting. In the case of gill nets with side lines, the depth of the side line is drawn same scale to float line. The width of netting panels, or sections of trawl are drawn as a half of the stretched netting width, and the depth or length according to the vertical hanging ratio of netting. Some

Table 6. Amount of fishing gear designs and technical papers collected from the surveys in Vietnam .types of fishing gear are shown by schemata or overall sketches with the dimensions indicated applicably.

      2) General outline drawings, such as of the rig of a complete gear, and detailed drawings of components, are not to scale, but the main dimensions are given.

     3) Dimensions are given only in meters (m) and millimeters (mm). The units are not indicated but can be easily be recognized, as follows:

Meter : Length of footropes, headlines, floatlines, etc. used with decimals of hundredths (e.g., 5.25, 90.20).

Millimeter : Mesh size (stretched), diameter of ropes, floats, etc. used without decimal or with decimals of tenths (e.g., 15; 325 or 2.5 ; 15.8)

     4) Mass and weight are indicated in the units of kilogram (kg) and gram (g). Buoyancies of floats and sink load of net yams or ropes are shown by kilogram-force (kgf) or gram-force (gf).

     5) Materials are indicated by abbreviations listed in Appendix 1.

     6) The size of net yarns is shown in the denier unit.

     7) The mesh size given in millimeters (mm) is understood to be the distance between the centers of two opposite knots in the same mesh when fully stretched.

     8) The number of meshes in a straight row along the edge shows the width and length or depth of net panels or sections.

     9) The shape of netting section is indicated by the cutting rate at its edge. A tabulation of common cutting rates for a practical rang of taper ratios is shown in Appendix 2 .

   10) The term hanging ratio (E) designates the ratio between the length of a given portion of the mounting rope and the length of the stretched netting hung on this portion of the rope.

   11) When there are two or more variants in the construction of gear or manner of use, there are indicated in the title and opposite thedrawing by Roman numerals (I, II,...). Where these variants refer to only one component part of gear, other possible ways of making this part are shown with the abbreviation ALT.

   12) Sequence in fishing operation is shown by sketches with circled Arabic numerals (1, 2,...) which indicate the sequence of operational stages.

   13) Parts of gear drawn in detail are indicated by circled capital letters (A B...).

Figure 1. Location of fishing gear and metfod survey in the Vietnam       

Appendix 1: Abbrivations and symbols used in illustrations

Apppendix 2: Common Cutting Rates and Taper Rations

Row: Number of meshes depth

Column: Number of meshes lost ( or gained )