|
|
|
Poster Session
|
Utilization of satellite Remote Sensing for exploitation of anchovy, sardine and other commercially utilized fishes
Wang Faji
Yellow Sea Fisheries Research Institute, Qingdao, China
Han Shixing
East China Sea Fisheries Institute, Shanghai, China
Jin Manyi
Chinese Academy of Fishery Science, Beijing, China
Abstract
The present paper deals with utilization of IR and visible images of NOAA satellite to analyse the formation and structure of fishing grounds of anchovy (Engraulis japonius), sardine (Sardinops melanosticta), blue-spotted mackerel (scomberomorus niphonius), mackerel (pneumatophorus japonicus ) and round scad (Decapterus maruadsi), and prediction experiments on the fishing grounds of blue-spotted mackerel, mackerel and round scads.
Intouduction
In 1986-1989, according to instruction from fishery Department of the Ministry of Agriculture, a series of experiments was conducted on satellite remote sensing technology applied to fisheries in Chinese coastal regions. The present paper discusses the utilization of satellite remote sensing images for analysing formation and structure of fishing grounds of anchovy, sardine, blue-spotted mackerel, mackerel and round scads.
Material and method
- Data of fishing grounds: those used fishing records made by Chinese research vessels, experimental-fishing vessel and fishing vessels.
- Data of satellite: those used were remote sensing data of meteorological satellite NOAA obtained by Chinese meteorological departments.
- Technical measures and methods
- Satellite images selected were processed by computer according to the procedures of image enhancement, mapping isotherms, atmospheric correction, projection transform and density slicing.
- Processing of satellite images was done according to living habits of target species to get prediction index which could correctly reflect fishery information law.
- To improve precision of prediction , analysis and prediction of fishing grounds were by using method of comprehensive study of information.
- Various types of satellite remote sensing information were transferred by wire or wireless fax, telegram and mail:
Analysis of formation of fishing grounds
- Fishing ground of anchovy in wintering migration.
The chief reason for fish's wintering migration is that the temperature in feeding grounds gradually drops and the fish are compelled to move to waters where the environment is favourable for their growth.
Anchovy are migratory pelagic fish in the Yellow sea and the East Chinese Sea. In every Autumn, as temperature declines, anchovy begin to make their wintering migration, Leaving spawning and feeding grounds southwards for deeper waters. The suitable temperature range for anchovy in wintering period is 8-15°C, optimal from 11 to 13°C.
Satellite IR images of December 1986-March 1987 systematically reflected variation characteristics water temperature in the Yellow Sea in winter. In the period of November-December, water temperature in the area north 34°N, west 124° E generally ranges from 9-12° C. Therefore, in the period of November - December anchovy may migrate over a vast area, the population scattering. After January of next year, water temperature in the yellow Sea changes considerably. As indicated in fig. 1, cold water mass in coastal area of northern jiangsu province obviously expanded toward of - sea and water temperature in the area north 34°N, west 124°E, generally droped to below 9°C. A "s" typed distribution of dense isotherms of 11-13°C occurred at the area where the coastal water north Jiangsu and the Yellow sea warm current converged. Owing to smaller range of this "s" typed area, it could be deduced that under the effect of barrier provided by coasted could water of northern Jiangsu province, anchivy began to aggregate and population density became higher. The result of routine investigation revealed that in November to December both average M value and catch of anchovy were at lower level (M value shows relative value of school density by acoustic method to survey and evaluate fish stack), and only after January next. Year , both M value and catch of anchovy would increase evidently. The areas with a larger M value value and fish catch were located in the limits of 11~13°C isotherms illustrated on satellite images dated 14 January 1987.
|
|
|
|
|
|
|
