South Heart River Walleye
Project 2004
Author(s)
Leanne Osokin and John Tchir
Summary
This data report describes the results of radio telemetry studies on Lesser Slave
Lake walleye (Sander vitreus) captured in the South Heart River drainage. The
objectives of the study were to document spawning and post-spawning
movement patterns of walleye in the South Heart-Buffalo Bay area and that in
the west bay of Lesser Slave Lake. The Alberta Conservation Association
conducted this study to provide Alberta Sustainable Resource Development with
information that they could consider when evaluating the need to revise angling
regulations to exclude harvest of walleye in a seasonal closure zone (west bay,
Grouard channel and tributaries) from March 1 to June 15. This report describes
results compiled over the two-year study period that was initiated in April 2003.
Over the course of this study, 89 adult walleye were implanted with radio
transmitters (68 in 2003, 21 in 2004). In 2003, fish were tracked over a 14-week
period (12 May to 18 August 2003) with 19 fixed wing aerial telemetry surveys.
Similarly in 2004, walleye were tracked over a 16-week period (29 April to 18
August 2004), comprising surveys completed using fixed wing (14 surveys),
helicopter (two surveys), canoe (four surveys), and power boat (six surveys).
In 2003, we recorded a total of 307 locations of the 68 walleye implanted with
transmitters. During 2004, 236 locations were recorded from 49 implanted
walleye. Of the 68 walleye implanted in 2003, 28 were relocated during the 2004
survey period. In 2003, we were only partially successful in quantifying
spawning movements of walleye due to later season implant dates; one walleye
was recorded upstream of Buffalo Bay. In 2004, we documented 23 individual
walleye upstream of Buffalo Bay from 10 - 31 May. Movement out of Buffalo Bay
and upstream tributaries were comparable for both years, as walleye were not
detected in this area after 9 June in 2003 and 7 June in 2004. On 16 June 2003, (one
day after the seasonal closure) 14 implanted walleye were found within the
seasonal closure zone of Lesser Slave Lake in comparison to four walleye
relocated in this zone on 17 June 2004. As the season progressed, data from both
years showed that walleye use of the seasonal closure zone was minimal; three
implanted walleye relocated on 18 August 2003 and two recorded on 27 August
2004. Over the course of the study, anglers removed five implanted walleye
while two were reported as caught by anglers but were subsequently released.
Although, it is highly likely that more implanted walleye were harvested, we
cannot quantify actual levels of angler-induced mortality. In 2004, we tested the
following telemetry assumptions: effectiveness in relocating transmitters from
various modes of travel and the accuracy of the relocations. The results indicated
that we relocated between 50 – 68% of walleye that had implanted transmitters
when all survey modes were combined. Analyzing modes of travel for telemetry
surveys separately, showed that telemetry reconnaissance conducted using a
canoe was the most effective (i.e., 75% success) and accurate (i.e., within 49 m on
average) in relocating transmitters. Surveys completed during the spring of 2004
indicated that walleye occurred in Horse Lakes, a shallow wetland area that
drains into Buffalo Bay. It is believed that this area, while unsuitable for
spawning, may be an essential feeding, staging area during the spring spawning
and post-spawning phase movements.