An accurate assessment of forage fish abundance in the Great Lakes will prevent over-stocking (or under-stocking) of predatory salmonids and allow for a better utilization of the fisheries potential of these lakes. Assessment in Lake Baikal, Russia is critical for quotas of the major commercial fishery in that lake. Similar questions require attention in other parts of the nation and the world. Our standard operating procedures are being implemented in major fisheries acoustics software packages and are used worldwide.
impact statement issue
Hydroacoustics is commonly used in marine systems for estimating fish abundance and setting harvest quotas. There is large potential for using this technique in freshwater systems as well. Problems include definition of noise thresholds, separation of invertebrate from fish echoes, separation of different fish age groups, and proper survey designs. There is a need for a standard operating procedure that spans lakes, different manufacturers, and software.
impact statement response
We have developed the necessary equations for applying hydroacoustics to Lake Erie and Lake Champlain smelt populations. Our work includes algorithms for separating invertebrates from fish, for separating different fish age groups, and for subtracting depth dependent noise levels. These methods are being applied to acoustic estimates of smelt in Lake Erie and Lake Champlain, alewife and smelt in Lake Ontario, and omul in Lake Baikal. We have produced version 1.0 of a standard operating procedure that was published in 2009 as a Great Lakes Fisheries Commission's Special Publication and a summary in the ICES Journal of Marine Research. We have also revised and resubmitted a chapter on acoustics to be part of fisheries techniques book by the American Fisheries Society. Further, we have developed a website, Acoustics unpacked, with access to the SOP and interactive equations. Acoustics is becoming a cost-effective method for standard fish sampling across New York.
impact statement summary
We have developed standard operating procedures for hydroacoustic surveys in the Great Lakes that are now published through the Great Lakes Fisheries Commission. We are also developing teaching tools, a web site is online and operational (Acoustics unpacked), and have contributed a chapter in the American Fisheries Society's textbook on Fisheries Techniques. Standardization of techniques and a better appreciation for the uncertainties in this technique will increase its usefulness in the Great Lakes and elsewhere.
Other private funding
Great Lakes Fisheries Commission\New York Sea Grant
