Does a change in ocean environment result in a change in fish distribution and migration?
Echo integration was considered the most important technique for studying fish distribution. For fish distribution studies near physical phenomena such as ocean fronts, vessel surveys must extend over sufficient distances to describe the distributional (vertical and horizontal) characteristics at an appropriate scale to characterize each environment. To facilitate scaling of echo integration information, target strength data should be collected when possible. The group felt that, in most marine situations, it is dangerous to scale echo integration results by simultaneously collected target strength data because of limitations in target strength measurements related to the stringent conditions required for target strength measurement procedures. Because the interaction between fish species and other trophic levels is going to be important to many GLOBEC questions, multiple frequency instruments are recommended. Frequencies commonly used for echo integration systems include 38, 120, 200,
