Horizontal acoustic surveys and fish behaviour in the open water

Project No. 206/07/1392

Applicant: As./Prof. Jan Kubečka, PhD.

Financial support: Czech Science Foundation

Duration: 2007-2010

Most fish of the open water of large reservoirs of Czech Republic (also applies to many lakes and reservoirs worldwide) inhabit surface layers where they can be studied quantitatively preferably by horizotal acoustic surveys. The aim is to solve main persistent problems of horizontal surveying like undefined behaviour of ultrasonic field, uncertainty of fish size estimates, microdistribution, discrimination between small fish and bubbles, influences of swimming behaviour and diurnal changes of behaviour. The emphasis is on improvement of quality of mobile surveys with large spatial coverage. The problems will be solved by the combination of (i) klassical split-beam echosounder, (ii) newest commercially available high frequency multibeam sonar Didson, which has theoretically a number of advantages (iii) direct fishing and optical approaches. Project should significantly improve horizontal detection of fish, interpretation of records and elucidate a number of patterns of pelagic behavoir of fish which is insufficiently known in fresh waters.