Warner Lake Ecological Observatory: Insights into Fish Behaviour Using a Whole-Lake Three-Dimensional Acoustic Telemetry Array K.C. Hanson 1, S.J. Cooke 2, C.D. Suski 3, G. Niezgoda 4, F.J.S. Phelan 5, R. Tinline 6, and D.P. Philipp 1 1 University of Illinois at Urbana-Champaign; 2 University of British Columbia; 3 Ontario Ministry of Natural Resources; 4 Lotek Wireless Inc.; 5 Queen’s University Biological Station; 6 Queen’s University ACKNOWLEDGEMENTS ABSTRACT The Warner Lake Ecological Observatory is located on the property of the Queen’s University Biological Station and represents the first whole-lake experimental system capable of monitoring the behaviour of fish in three dimensions. The acoustic telemetry system uses code discrimination multiple access (CDMA) protocols to enable the simultaneous real-time monitoring of numerous tagged animals. During preliminary experiments, 22 largemouth bass (Micropterus salmoides) were implanted with acoustic transmitters in November, These transmitters provided the positional information required to generate X-Y-Z positions and temperature of each animal every 15 seconds. Transmitter signals were collected by a series of 13 moored hydrophones that relayed information to two receiving stations. This initial phase of the project produced a comprehensive dataset of fish behaviour from November, 2003 through April, Individual movements across various time scales (e.g., gross daily movement to instantaneous movements) were recorded with sub-meter accuracy. During the winter, fish resided in the deep basin of Warner Lake and avoided the shallow basin. Contrary to existing paradigms that largemouth bass are quiescent during the winter, fish moved extensively under the ice, exhibiting subtle but regular patterns of vertical distribution. In late March ice cover left the shallow basin before the deep basin, and the majority of individuals moved into the ice-free basin. This preliminary deployment using largemouth bass as a model has revealed the power of the ecological observatory to provide data that are unattainable using other techniques and will enable a better understanding of the community ecology in temperate lakes. Warner Lake Ecological Observatory The Warner Lake Ecological Observatory represents a unique approach to the address questions concerning the ecology of freshwater fish on both an individual and population level on a whole-lake scale. Continuous, remote monitoring of tagged individuals’ movements allow for the creation of a massive, detailed, and extremely accurate database of largemouth bass movements across multiple seasons with comparatively minimal effort expended on the part of researchers CDMA protocols allow multiple individuals to be implanted with transmitters that all function on the same frequency and then tracked simultaneously The current database of transmissions represents one of the most comprehensive and detailed assessments of largemouth bass movements and behaviours across multiple seasons GOAL To develop and deploy a telemetry system capable of continuously monitoring the three dimensional movements and behaviours of multiple largemouth bass remotely on a whole-lake scale To utilize the developed database to answer questions in to the behaviour of largemouth bass individuals and populations across multiple seasons METHODS In 2003, the Warner Lake Ecological Observatory, an acoustic telemetry array consisting of 13 moored hydrophones and two fixed receiving stations, was donated and installed at Queen’s University Biological Station The system utilizes CDMA protocols to simultaneously monitor the movements of multiple individuals implanted with transmitters on the same frequency In November 2003, as a pilot study, twenty two adult largemouth bass were implanted with acoustic transmitters that provide information on three dimensional position and temperature with a transmission rate of every 15 seconds The Warner Lake Ecological Observatory continues to produce one of the most detailed and accurate databases of freshwater fish movements across an entire year that can be queried to answer a multitude of research questions. For the first time it will be possible to model the energetic costs of fish behaviours over an entire year. It will also be possible to examine the winter ecology of fish under the ice, providing insights into constraints on growth and survival, as well as the spatial ecology of fish. Knowledge of animal distribution and behaviour during the winter are essential to protect critical habitats Long term monitoring of individual fish will enable us to explore questions about the behaviour and activity of fish that reproduce in a given year in contrast to those that forego reproduction. The array also provides future researchers with a chance to address questions on organisms as disparate as water snakes, snapping turtles, waterfowl, and white suckers, as well as interactions among multiple members of a lake community. FUTURE RESEARCH FIG 2. FINDINGS Simplistic Overview of an Acoustic Telemetry Array and Array Deployment SUMMARY OF FINDINGS Initial deployment and subsequent system testing have demonstrated the feasibility and accuracy of the whole-lake, acoustic telemetry system in monitoring the simultaneous, real-time movements of multiple individuals utilizing CDMA protocols. Preliminary experiments have shown the benefit of using this approach in investigating behaviors of largemouth bass on both individual and population level scales. Simplistic rendering of a continuous, remote monitoring acoustic telemetry system Surgical implantation of an acoustic transmitter into the intraperitoneal cavity Deployment pattern of moored hydrophones in the two basins of Warner Lake Individual movements across a 24 hour period in the fall of 2003 FIG 3. FIG 1 Transmitter Implantation and Release Live release of a telemetered largemouth bass Trace of a tow trial test to show accuracy of array at monitoring movements in all areas of the lake FIG 4. Movements of five individuals (each represented by a separate color) across the same time period in the spring of 2004 Plot of average depth by average temperature for all fish across November and December of 2003 Examples of Array Data Gathered from Multiple Individuals Examples of Individual Movement Traces