a series of activities that include searching for, observing, and assessing the commercial value of aggregations of marine organisms (fish, mollusks, crustaceans).
Fishing survey is usually broken down into search operations and the survey proper. The search includes preliminary determination of the distribution of the target organisms, identification of regions favorable for the formation of aggregations, and the actual search for the aggregations. The survey involves determining the size and value of the aggregations, making short-term forecasts of the stability and movement of the aggregations, and guiding the fishing fleet to the marine animals.
Fishing survey involves both exploratory and operational work. The first includes the search for new fishing regions and commercial targets. The formation of commercial aggregations and their paths of migration are studied, as is the behavior of marine organisms in different periods of the year. Aggregations
|Table 1. Fineness of metals and alloys in the USSR|
|Metric system||Zolotnik system||Carat system||Alloy color||Hardener||Basic use|
|1 Large quantities used during the Great Patriotic War (1941-45)2 Most widely used alloy in USSR3 Most widely used alloy in Western Europe 4 Of no practical significance in the USSR 5 Range of 10 fine|
|Green||Silver, copper||Individual parts injewelry|
|Pale yellow1||Silver||Filigree work|
|375||—||—||Red1||Copper, silver||Jewelry and watchcases|
|Pink||Silver, palladium, copper||Wedding rings|
|960||—||—||White||Copper||Delicate filigree work|
|916||88||22||White||Copper||Filigree work, enameled articles|
|875||84||21||White2||Copper||Jewelry and domestic items|
|800||—||—||White3||Copper||Jewelry and domestic items|
|750||—||—||White with slight yellowish lint||Copper||Jewelry, fashion accessories|
|850||—||—||White||Silver, nickel||Wedding rings, in combination with gold 583 fine|
|1,000||—||—||Yellow||Gilding of bas-reliefs on buildings, monuments, church domes|
|1,000||—||—||White||Silvering of bas-reliefs on buildings, monuments, church domes|
are evaluated, and the economic viability of exploiting them is determined. Operational work involves guiding fishing vessels to schools of fish, making recommendations concerning the deployment of the fleet, and observing hydometeorological and other working conditions.
Fishing survey employs direct and indirect methods. Among the direct methods are sample fish catches and the use of such detecting devices as sonar fish-finders. Indirect methods include the determination of the position of aggregations on the basis of environmental conditions. The indirect approach is the primary one, with direct survey used mainly to confirm results obtained indirectly. Fishing survey is based on the study of those environmental factors (for example, water temperature) that determine the range of fish distribution. It also takes into account seasonal physiological changes undergone by the animals.
Fishing survey employs the experiences of many sciences, including ichthyology, oceanography, hydrochemistry, and hydroacoustics. It is conducted through the use of fish-finding equipment mounted on ships, airplanes, and helicopters. In the USSR, specialized organizations of the fishing industry are involved in fishing survey.
V. M. LIFSHITS