One would send out sound waves that would bounce back. They would be received by a second ship, and that would give us very precise estimates, in this case, of 250 billion herring in a period of about a minute.
Uno emitía ondas acústicas que se reflejaban y eran recibidas por el segundo barco y, en este caso, nos dio estimaciones muy precisas de 250 mil millones de arenques en aproximadamente un minuto.