Curious About Kanaskis Area

[jpinkster]

An interesting read on the history of the Upper K Lakes from the 2010-2011 Creel Survey:

Upper Kananaskis Lake was barren of sport fish prior to the stocking of Rainbow Trout Oncorhynchus

mykiss in 1935 (Rawson 1937). Based on the initial success of this stocking, Rainbow Trout were stocked

intermittently until 1968, and then annually until 1986, usually with fish no larger than 15 cm (Table 1).

However, despite the frequent stocking of relatively large numbers of fish, a 1983 creel survey revealed

that Upper Kananaskis Lake provided a very poor fishery (mean catch rate of 0.1 trout/h, including fish

released) at a very high cost ($116/kg of trout harvested) (Stelfox 1985).

To try to provide a better and more cost-effective fishery, several fisheries management changes were

subsequently implemented. From 1984 to 1986, Westslope Cutthroat Trout Oncorhynchus clarkii lewisi, a

species native to nearby Lower Kananaskis Lake, were stocked in the hopes that they might survive better

than the stocked Rainbow Trout, which are not native to this watershed. However, subsequent gillnetting

in 1986 (Stelfox 1987) and 1987 (file data) failed to provide any evidence that the small (4 cm) stocked

Cutthroat Trout survived better than the substantially larger (primarily 10–15 cm) Rainbow Trout stocked

during the same time period.

Based on studies which showed that stocking large trout provided much better returns than stocking small

trout in reservoirs with widely fluctuating water levels (Rogers 1980; Sealing and Bennett 1980), a

recommendation was made to stock larger (>20 cm) Rainbow Trout in Upper Kananaskis Lake (Stelfox

1987). Subsequently, from 1992 to 2002, Upper Kananaskis Lake was primarily stocked with large (≥20

cm) Rainbow Trout (Tables 1 and 2). Anecdotal reports from anglers suggested that this improved the

fishery, but no creel data were gathered to corroborate these claims.

In the early 2000s, several changes in fisheries management occurred at Upper Kananaskis Lake, with

the major change being a shift towards providing a fishery for native trout species. Beginning in 2001, Bull

Trout Salvelinus confluentus, originating from the native population in Lower Kananaskis Lake, were

stocked in Upper Kananaskis Lake and have been intermittently stocked since then (Table 2). The

Upper Kananaskis Lake creel survey: 2010 and 2011 2

rationale behind this change was that Bull Trout should have better growth and survival than Rainbow

Trout in Upper Kananaskis Lake, since they are more likely to occupy the part of the water column where

Opossum Shrimp Mysis relicta occur and, being highly piscivorous, could also exploit the abundant forage

base of minnows (Lake Chub Couesius plumbeus and Longnose Dace Rhinichthys cataractae) and

introduced suckers (Longnose Sucker Catostomus catostomus and White Sucker C. commersonii)

(Stelfox 1987).

In 2002, a minimum size limit of 30 cm was implemented for Cutthroat and Rainbow Trout in Upper and

Lower Kananaskis lakes and the bag limit for Cutthroat and Rainbow Trout was reduced to three (from the

previous limit of five). A bait ban was also implemented on Upper Kananaskis Lake in 2002, so as to

improve survival of released Bull Trout — protected since 1995 by a province-wide, 0-bag limit — and

undersized Cutthroat and Rainbow Trout. Finally, the stocking of Rainbow Trout in Upper Kananaskis

Lake ceased after 2002 and was subsequently replaced by alternate-year stocking of primarily large (≥20

cm) Westslope Cutthroat Trout, beginning in 2003.

Subsequent gillnetting, conducted in 2006 and 2007 (Earle and Stelfox 2012), revealed that Bull Trout

survival and growth was very good, with most Bull Trout exceeding 40 cm. In contrast, Cutthroat Trout

survival appeared to be relatively poor, since they comprised a relatively small proportion of the gill net

catch and most were smaller than 40 cm. This raised the question as to whether the relatively small

numbers and sizes of Cutthroat Trout was due to predation by Bull Trout, harvest by anglers, or both. To

address this question, and determine what size of Cutthroat Trout should be stocked to provide a more

cost-effective fishery, Upper Kananaskis Lake was stocked with different sizes of Cutthroat Trout —

unmarked 19-cm and 20-cm Cutthroat Trout in 2009 and 2011, respectively, and marked (fin-clipped) 30-

cm Cutthroat Trout in 2010 (Table 2).

In 2010, a number of anglers expressed concern that the 30-cm minimum size limit provided inadequate

protection for recently stocked Cutthroat Trout, thereby preventing the Kananaskis Lakes from realizing

their potential to provide high quality fisheries. To rectify the situation, they proposed that the Cutthroat

Upper Kananaskis Lake creel survey: 2010 and 2011 3

and Rainbow Trout minimum size limit should be increased to 50 cm and the bag limit should be reduced

to one fish.

To evaluate, from the anglers’ perspective, the effectiveness of stocking Cutthroat Trout of different sizes,

a creel survey was conducted during the summers of 2010 and 2011. The creel survey also gathered

information on the size distribution of harvested Cutthroat and Rainbow Trout relative to the proposed 50-

cm minimum size limit. This report presents the results of that survey.

[halcyonsancta]

Fishing from the eastern shore of Upper K Lake I have watched a 10" Bull Trout chasing a 16" Rainbow in about 2 feet of water. It went on for a long time, they would move out of sight into deeper water and then 15 minutes later they were back in the shallows again, this repeated 4 times in total. I could cast right to them but they took no notice. They turn on a dime in very small diameter circles. It was interesting to observe.

[monger]

I am curious halcyonsancta, when was the last time you caught a rainbow out of Upper Kan lake?

[halcyonsancta]

Never