Warner Lake Ecological Observatory: Insights into Fish Behaviour

1
Warner Lake Ecological Observatory Insights
into Fish Behaviour Using a Whole-Lake
Three-Dimensional Acoustic Telemetry Array
K.C. Hanson1, S.J. Cooke2, C.D. Suski3, G.
Niezgoda4, F.J.S. Phelan5, R. Tinline6, C.T.
Hasler6 and D.P. Philipp1
1University of Illinois at Urbana-Champaign
2University of British Columbia 3Ontario
Ministry of Natural Resources 4Lotek Wireless
Inc. 5Queens University Biological Station
6Queens University
ABSTRACT A whole-lake acoustic telemetry array
was utilized to monitor the three-dimensional
position of 20 largemouth bass (Micropterus
salmoides) as part of an ecological observatory.
Code discrimination multiple access (CDMA)
technology enabled the simultaneous monitoring of
the 20 transmitters (equipped with pressure and
temperature sensors) at 15 sec intervals with
sub-meter accuracy. We used three representative
days between November 2003 and April 2004 to
evaluate the behaviour of fish across different
temporal and spatial scales. The distance moved
by largemouth bass, assessed both on a daily and
hourly basis, varied by season and was positively
correlated with water temperature. Daily
movement rates were 2.69 1.45 km/day in late
November (average daily water temperature 5.9ºC),
2.24 0.73 km/day in early January (5.1ºC), and
7.28 2.62 km/day in April (7.7ºC).
Interestingly, daily movement rates varied by as
much as 25 fold among individuals. Visualization
of fish swimming paths revealed that some fish
occupied discrete areas and made only localized
movements, whereas other individuals made
lengthier journeys covering much of the lake in
periods of as little as one day. Analysis of
fish behaviour at a finer temporal scale revealed
that during the winter, fish spend more than 95
of their time swimming at speeds less than 0.1
m/sec (0.07 0.24 m/sec). During late fall, and
especially in spring, swimming speeds were higher
with mean swimming speeds of 0.11 0.27 m/sec
and 0.19 0.29 m/sec, respectively. An analysis
of associations (average hourly X,Y,Z position of
two fish with in 2 m of each other) among the 20
fish was also carried out using the array. It
was found that fish do in fact associate in
groups and there is a spatial component to the
associations. This study identifies the
importance of evaluating fish activity at
multiple spatial (whole lake to sub-meter
position) and temporal (seasonal to seconds)
scales and illustrates the potential of CDMA
telemetry to yield such data.
FINDINGS
FIG 1
Transmitter Implantation and Release
Average depth, temperature, and daily distance
traveled across the Winter season, 2003-2004
Tracks of six individual largemouth bass on April
13, 2004
Spatial and Temporal Relations
FIG 2.

• 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

Instantaneous swimming speeds by position
estimates for two individuals across seasons
Daily distance traveled by individual for all
seasons
Inter-individual Associations
FIG 3.

• 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 Queens
  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

Surgical implantation of an acoustic transmitter
into the intraperitoneal cavity
McQuitty Linkage analysis of the groups of
associating fish and their members
Kernel Density Estimation of the location of the
associations.
Observatory Consortium
Live release of a telemetered largemouth bass