Status of Northern Pike and Yellow Perch at Goosegrass Lake, Alberta, 2006
Nathan Carruthers, Tyler Johns and Greg Fortier
Increased access in the Red Earth region of northwestern Alberta has raised concerns about impacts of potential increases in angling pressure on sportfish populations of lakes in the region, including Goosegrass Lake. The present study was conducted at Goosegrass Lake to generate quantitative data on abundance, population structure and growth of two major species, northern pike (Esox lucius) and yellow perch (Perca flavescens), that can be used to assess impacts of increased fishing pressure.
A total of 225 sportfish were captured during the survey. Northern pike was the most abundant species captured, accounting for 74.6% of the catch, and yellow perch was least abundant, accounting for 25.4% of the catch.
Mean catch-per-unit-effort (CPUE) for northern pike ranged from 16.18 to 21.29 fish/100 m2/24 h with a total CPUE of 18.00 fish/100 m2/24 h. Of the 168 northern pike sampled, 46% were females and 54% were males resulting in a female to male sex ratio of 0.87:1. Total length (TL) of females ranged from 430.3 to 828.0 mm with a mean (± SD) of 695.5 ± 78.0 mm. Males ranged in length from 496.6 to 747.2 mm with a mean of 640.6 ± 55.9 mm (n = 89). Male northern pike ranged in age from 4 to 11 y (mean = 7.33 ± 1.62 y; n = 89), whereas females ranged from 3 to 13 y (mean = 7.66 ± 2.10 y; n = 77); overall mean age of the catch was 7.45 y ± 1.90 y (n = 167). Age-8 males and age-6 females with mean TLs of 668.7 ± 17.80 mm (n = 27) and 652.9 ± 24.74 mm (n = 18), respectively, were the most abundant year-classes representing 26.8% of the total catch.
Mean CPUE for yellow perch ranged from 5.83 to 6.56 fish/100 m2/24 h with a total CPUE of 6.11 fish/100 m2/24 h. Of the 56 yellow perch caught, 60.7% (n = 34) were females and 5.4% (n = 3) were males resulting in a female to male sex ratio of 11.33:1. Predicted TL of females ranged from 92.8 to 245.0 mm with a mean of 193.2 ± 8.69 mm (n = 34), whereas length of males ranged from 161.6 to 218.9 mm with a mean of 192.7 ± 28.84 mm (n = 3). Male yellow perch ranged in age from 8 to 9 y (mean = 8.5 y, n = 2), whereas females ranged in age from 2 to 9 y with a mean of 5.79 + 2.00 y (n = 33); overall mean age of the catch was 5.72 ± 2.10 y (n = 39). The age-6 cohort with a mean TL of 198.9 mm ± 6.09 mm (n = 8) was the most abundant year-class, representing 20.5% of the total catch.
The results of the present study provide important baseline information that can be used by resource managers to quantify the effects of anticipated increases in angling pressure on sportfish population in Goosegrass Lake.