Fishing vesselThe term "fishing vessel" is used instead when the vessel is engaged only in catching operations. Non-Fishing VesselThe term "non-fishing vessel" applies to vessels performing other functions related to fisheries, such as supplying, protecting, rendering assistance or conducting research or training. In order to assess fleet capacity it is necessary as a bare minimum to have estimates of vessel numbers and main vessel characteristics. If the fleet consists of only one type of vessel, the number of fishing vessels can be used to express the total fishing power or capacity of the fishing fleet. If the fleet consists of vessels of different designs, any survey to determine the capacity of a given fishing vessel would need to collect information on a number of vessel characteristics. Gross tonnage (GT), length and engine power would be amongst the most important characteristics, and it is likely that gross tonnage would be the most important single variable influencing fishing capacity. In international law, as well as in practice, several systems of tonnage measurement have existed side by side. Traditionally, records of measurements of a ship's size were expressed in tons of 100 cubic feet each (GRT); tonnage was used as a basis for taxes, berthing, docking, passage through canals, and other facilities. However, the method of tonnage measurement has evolved and differs considerably from country to country. A number of international meetings on the subject concluded with the International Convention on Tonnage Measurement of Ships, held in London in 1969. The Convention, commonly known as the 1969 Tonnage Convention, entered into force in July 1982, though existing ships were not required to comply with the Convention until July 1994. At that time, gross tonnage, as defined by the 1969 London Convention, became obligatory for all vessels of 24 metres in length and over, and engaged in international voyages. Until 1994 the system of tonnage defined by the Oslo Convention (1947, using the Gross Register Ton GRT as unit of measurement) continued to be valid. Although the London Convention has been adopted for vessels of 24 metres in length and over, for many vessels only data by the Oslo Convention are available. The situation varies from country to country, as measuring units defined at national level can also be used to determine the tonnage of vessels operating without an international tonnage certificate. The two conventions produce very different tonnage values. Although GT measurement is higher than GRT, there is no simple correlation between the two units (GT is often double the GRT, but sometimes as much as four times the GRT). The magnitude of the task of reaching international agreement on standardized measurement units, of introducing these units into national regulations, of re-measuring all fishing vessels is a very lengthy, complex and costly process. For statistical purposes two main classifications were adopted by the CWP for classifying fishery vessels by tonnage and types: 1.The "International Standard Statistical Classification of Fishery Vessels by GRT Categories" (ISSCFV), based on the Gross Register Tonnage of the vessels, approved by the CWP (Coordinating Working Party on Fishery Statistics) in 1977. See Annex L. I. 2.The ’International Standard Statistical Classification of Fishery Vessels by Vessel Types’ (ISSCFV), based on the type of gear used by the vessels, approved by the CWP in 1984. See Annex L. II. Based on the international convention in use, FAO fleet data on the vessel tonnage are measured according to the Oslo Convention (1947) expressing data by Gross Register Tonnage (GRT) until 1995; and according to the London Convention (1969) expressing data in Gross Tonnage (GT) since 1996. Gross Register TonnageThe Gross Register Tonnage represented the total measured cubic content of the permanently enclosed spaces of a vessel, with some allowances or deductions for exempt spaces such as living quarters (1 gross register ton = 100 cubic feet = 2.83 cubic metres). Gross TonnageThe Gross Tonnage for ships of 24 metres in length and over refers to the volume of all ship's enclosed spaces (from keel to funnel) measured to the outside of the hull framing. Data on fishery fleet are collected by means of the statistical questionnaire FISHSTAT FF. Form FF1 is used for the collection of data on "decked vessels", whereas form FF2 is intended for "undecked vessels" for which the most important distinction is made between "powered" and "not-powered" crafts. Starting with the collection of data for 1996 several other changes were implemented in the FISHSTAT FF inquiry: non-fishing vessels were excluded from the inquiry (see Annex L. III), numbers and capacity data are now collected for broad groups of fishing vessels types and length overall has been defined as the main characteristic of measurement in international data collation (see Annex L. IV).
FAO. "Fishery fleet statistics, (1970, 1975, 1980, 1985, 1989-95)." FAO Bulletin of fishery statistics No. 35, 1998.  |
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