DEVELOPMENT AND UTILIZATION OF HYDROACOUSTIC METHOD
  	     OF SARDINE RESOURCES EVALUATION AND STUDIES OF A BEHAVIOUR

                               V.N.Vologdin, V.A. Belyaev


               TINRO-center, 4 Sgevehenko alley, Vladivostok, Russia

     Sardine is a specific object for hydroacoustic surveys, since this fish schools are 
very mobile  and are near  sea surface. Upper  and bottom  borders of these  schools 
coincide with  borders of different  densities of sea water  layers and are  in zone of 
internal waves action, is supplementary reason of not  stationarity of its location on a 
depth. concentrations  structure of this fish  is like spots  and density can  change in 
wide range within a 
twenty - four - hour period. Therefore specially for this species  as well as for other 
near  surface mobile  fish  species(mackerel etc.)  processing  similar  behaviour was 
developed hydroacoustic method considering these peculiarities. 
     Since  1982  for  the first  tine  we  began  to  apply  QM  - MKII  SIMRAD 
echointegrator and specially  designed for these surveys device for  a synchronization, 
commutations and  signals registration  (BSCRS). This device  allowed to  deduce all 
necessary information: hydroacoustic, oceanographic and navigation in sole registrator.
     During the period of  a Maximum quantity of sardine, in 1982 we  succeeded by 
hydroacoustic surveys transects to engulf the great  part of a feeding sardine area on 
the  Pacific  and  on  the  Sea  of  japan. A  general  area  of  contoured  the  fish 
concentrations  compiled  173.7591 billions  of  pieces,  Along  with this  quantity  of 
sardine is appraised in 564 billions of pieces, but biomass - in 26.3 millions of tons.
     According to  the data  obtained by sonar  tracking method were  built statistic 
distributions of velocities and directions of sardine schools movements. Characteristics 
of school velocities distributions are: =1.7
knots,  standard  deviation   Sv  =  0.5  knots.   Characteristics  of  school  courses 
distribution are:  = 179.4 , standard deviation Sq = 35.2 . Verification on pierson 
criterion showed accordance  of empirical velocities distribution to theoretical  Puasson 
law, but empirical distribution of school courses to theoretical normal distribution.
     Numerous  measurements also  showed the  most  probable velocity  of  sardine 
schools is 1.3 knots.
     Review of cases stationary and not stationary concentrations of  sardine bring in 
conclusion  that at  scorn by  velocities of  movement of  this fish  relative error  of 
evaluation of quantity can achieve 2o#%.
     Therefore this method  can be use for calculation  of abundance and biomass of 
sardine and another pelagic fishes in the North - West Pacific.