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Poster Session
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Utilization of satellite Remote Sensing for exploitation of anchovy, sardine and other commercially utilized fishes
- Fishing ground of sardine in spawning migration.
Sardine is coastal migratory pelagic fish. The fish make spawning from March to Jane every year, when sea surface water temperature reaches 14~15°C. Fishing ground of sardine in the distant areas of the East china sea and its adjacent waters is mainly distributed in convergence area of Tsushima warm current, Korean coastal waters and mixed water masses in the southern Japan Sea, and obviously near the side of Tsushima warm current. In fig. 3 it could be seen that central fishing ground is located in convergence area of cold and warm water masses where there are 15~17° C isotherms as illustrated on satellite images. The formation of fishing grounds like this is closely related with the feeding habit of sardine. Excluding postlarve stage, sardine feeds on phytoplankton in great quantities in very growth stage. As phytoplankton grows very well under favourable environment in which water temperature ranges from 15~17°C., suedine tends to aggregate in an area where cold and warm water masses converge within isotherms of 15~17°C.
- Fishing ground of blue-spotted mackerel in spawning migration.
Water transparency is one of important factors, which have influence on ecological habit of living organisms, therefore it is possible to infer the location of fishing grounds of some species according to distbution patterns of transparency. The fact has proved that fishing grounds of blue spotted mackerel in the southern Yellow Sea are located in convergence area of clear and turbid water and obviously near the side of turbid water as illustrated on images of satellite.
- Fishing ground of mackerel and round scads in feeding migration.
In the Taiwan straits, owing to the effect of topography and costal direction wind , there often occur in summer upwelling and eddy current which could bring bottom nutrients into sea surface, accelerating growth of live food organisms and forming favourable feeding ground for fishes. Bases on location of upwelling and eddy current illustrated on satellite IR images in the Taiwan straits in summer 1988, predictions about fishing groun of mackerel and round scads have successfully made. From the point of view of formation and structure of fishing grounds, above mentioned fishing grounds of anchovy, sardine and blue-spotted mackerel belong to front type and those of mackerel and round scads belong to upwelling and eddy current type.
Prediction effects
From the result of prediction experiments it has shown that satellite remote sensing technology play an important role in fishing production in Fujan province and Rongchen city, Shandong province.
- The result of comparison experiments revealed that the catch could be increased by 10~30% when fishing operation of blue-spotted mackerel was guided by satellite remote sensing data.
- Based on location of upwelling and eddy current illustrated on satellite images with routine investigation data, locations of fishing grounds of mackerel and round be quickly found out. The predicted locations of fishing grounds fundamentally coincided with those of practical fishing grounds.
Conclusion
- Sea condition information on the boundaries of water masses, upwelling , eddy current and transparency obtained from satellite images can provide important data for predicting fishing grounds of anchovy , sardine etc.
- Chinese coastal fishing grounds mostly belong to these of front, upwelling and eddy currently types, therefore the application of satellite remote, sensing technology to observe or study on the generation and disappearance of ocean front upwelling and eddy current is of great significance in prediction fishing grounds and guiding fishing production in Chinese coastal regions.
References
- Zhu De-shan et al. Marine Fisheries Research, 11 ( 1990) , 1.
- Cui Mingyan, Marine fishery, 8 ( 1986), 103.
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