Summer Sport Fishery and Special Harvest License at Pigeon Lake Alberta 2007
Author(s)
Bill Patterson
Summary
In 2006, Alberta Sustainable Resource Development (ASRD) initiated a pilot project on
Pigeon, Newell and Wolf lakes that allowed anglers to harvest walleye from these
previously closed fisheries through a Special Harvest License (SHL). Successful
applicants purchased a unique license and tag (i.e., similar to big game hunting
application and draw methods) that permitted them to harvest walleye within a
specified length category (i.e., > 50 cm, 50 ‐ 43 cm, < 43 cm total length, TL). Anglers not
in possession of a SHL followed the provincial regulation for each lake (i.e., zero bag
limit / catch‐and‐release).
To monitor the effects of SHL regulations on the sport fishery at Pigeon Lake, the
Alberta Conservation Association (ACA) conducted a summer angler survey from 19
May to 27 August 2007. The survey focused primarily on the walleye sport fishery,
although we also collected data on the northern pike sport fishery. We collected
information on angling effort, catch, and population structure, and calculated
uncertainty in angler survey parameters using a bootstrapping method. To collect yield
and biological data, we conducted angler surveys in combination with test angling.
Finally, we compared results of this study with those from previous surveys at Pigeon
Lake during the summers of 1999, 2003 and 2006.
During the 2007 survey period, we estimated 14,760 angling‐trips (95% CI = 13,045 –
16,594, n = 3,706 anglers) and 42,870 angling‐h (95% CI = 37,917 – 48,507, n = 10,959 h).
Angling‐pressure was 4.4 h/ha (95% CI = 3.8 – 5.0). However, angling pressure
associated with SHL anglers was a small portion of the sport fishery; only 22% or 3,247
anglers interviewed held a SHL. Angling pressure during the 2006 SHL season was
slightly higher (by 5%) than pressure during the 2007 SHL season. In addition, angling
pressure has increased nearly four‐fold since 1999. Of SHL anglers interviewed in 2007,
37% had not fished Pigeon Lake the previous year; this increase in SHL participation
may indicate a growing interest in the program.
SHL holders were permitted to harvest walleye from 18 May to 3 September 2007.
During the survey period (19 May to 27 August 2007), we estimated that anglers with
SHL tags harvested 2,729 walleye (95% CI = 2,277 – 3,245, n = 644). We estimated that
157,629 walleye (95% CI = 136,812 – 179,439, n = 37,741) were released by all anglers
(regular and SHL anglers combined), of which, SHL anglers released 15,199 walleye
(95% CI = 9,846 – 21,849, n = 10,909). The sport fishery harvested 0.27 kg/ha of walleye
and 0.42 kg/ha of pike. The yield associated with the release mortality of walleye
(estimated to be 5.3%) was 0.83 kg/ha (95% CI = 0.55 – 1.20) or approximately three
times that of the SHL harvest. We estimated that anglers harvested 509 pike (95% CI =
177 – 1,130, n = 73) during the survey period. SHL anglers accounted for 8% of the pike
harvest. Anglers released 2,417 pike (95% CI = 1,999 – 2,946, n = 567). Based on
proportion of the catch, SHL anglers released 22% of captured pike. The yield
associated with pike harvest and release mortality was 0.44 kg/ha.
According to Alberta’s Walleye Management and Recovery Plan, catch rates of walleye
were high. The length and age distributions of harvested walleye ranged from 427 to
718 mm TL and age‐7 to 10 and 13. Growth of walleye was moderately slow and
almost all harvested walleye were reproductively mature fish. The length distributions
of harvested walleye and test‐angled walleye were very similar (with the exceptions of
individual fish < 430 mm and > 550 mm TL). This similarity suggests that anglers were
not selecting the largest fish in their SHL length‐category, and instead were harvesting
the sizes of fish vulnerable to angling.
Relatively few pike were observed in angler harvests; thus, we also conducted test
fishing to help categorize the pike fishery. The estimated catch rate for pike was
extremely low; the total rate was 0.028 pike/h (legal‐size harvest rate = 0.005 pike/h,
protected‐size release rate = 0.023 pike/h). Based on test fishery data, we found the size
distribution of pike in Pigeon Lake to be severely truncated, possibly due to sizeselective
mortality and high angling pressure. The size distribution of pike was also
unstable, primarily supported by protected‐size fish (i.e., < 630 mm TL) with legal
length pike (> 630 mm TL) at very low numbers. However, the relative density of small
pike was substantial and may indicate considerable recruitment to the sport fishery in
the near future. The relative stock density (RSD) and the proportional stock density
(PSD) also indicated a truncated size distribution. The percent success and Gini
coefficient both indicated the chance of catching a pike was very low. These
parameters, including the extremely low catch rate, indicate a highly exploited pike
fishery in Pigeon Lake.