With experience, and with improved apparatus , it is now possible not only to locate a shoal but to tell if it is herring, cod, or other well-known fish, by the pattern of its echo.

• 根据经验和改进了的仪器，不仅能够确定鱼群的位置，而且可以根据鱼群回声的特点分辨出事鲱鱼、鳕鱼，还是人们所熟悉的其它鱼。