Echo sounding and sonar for fishing.

Manylion Llyfryddiaeth
Awdur Corfforaethol:	Food and Agriculture Organization of the United Nations
Fformat:	Llyfr
Iaith:	English
Cyhoeddwyd:	Surrey, England Fishing News Books c1980.
Pynciau:	Sonar in fishing. Echo sounding > fishing.