McGregor MN - Big Sandy Lake Association

Stocking of fish in Big Sandy

Report Received from Kit Nelson, DNR fisheries.
The gill net assessment on Big Sandy Lake was conducted to assess natural
reproduction of walleyes after stocking was discontinued in 1995. Many
stocking strategies have been utilized to increase the abundance of walleyes
in Big Sandy Lake without success. These have included fry stocking
(1917-1947), fingerling stocking (1951-1953, 1955, 1965, and 1968), annual fry
stocking (1983-1986), and high-density fry stocking on alternate years
(1987-1995). The results of assessments from 1947 through 1995 have shown
no significant change in the gill net catch for walleyes. Ineffectiveness of
stocking could be related to other factors, such as predator and prey
interactions rather than the actual numbers of fry stocked. The 1999
assessment indicated strong recruitment of walleyes for years after stocking
was discontinued. This suggests adequate spawning stock and habitat within
the lake for natural reproduction.

Tullibee abundance from gill netting averaged 3.9 fish per net lift. This
abundance is within the historical range of past surveys and was between the
second and third quartiles for lake class 22. Tullibee ages ranged from one to
eight (57 of 59 aged) with a strong year-class indicated in 1998. Growth from
scale analysis was normal when compared to the state averages in all but the
eight annual increments, which was below normal. Tullibbees were captured
only in Bill Horn Bay using regular gill net sets.

Northern pike abundance as indicated by the gill nets remained stable
averaging 5.6 per lift and is near the median for this lake type. Ages ranged
from one to seven (77 of 84 aged) and most pike, 94% were from the 1995
through 1998 year classes. Growth was normal for the first two scale
increments and slower than the state average thereafter. The average length of
northern pike was 18.1 inches compared to 17.6 inches in 1995. The
proportional stock density (PSD) of northern pike was 14 in 1999 and similar to
1995. The largest northern pike captured was 36.7 inches in Length.

The gill net index of abundance for black crappies increased significantly from
the 1995 survey (Wilcoxon sign rank test, n=6, p=0.036), and was above the
third quartile for this lake class. Ages ranged from one to four (29 of 29 aged)
and with one exception black crappies were from the 1997 and 1998
year-classes. Growth increments on scales were above average and normal for
the first and second years, respectively.

Yellow perch gill net index was 18.7 fish per net lift. This was near the second
quartile and similar to historical catch rates. Their ages ranged from the two to
eleven (87 of 281 aged) with strong year classes indicated for years 1992
through 1997. Growth as indicated by scale analysis was normal or above
average for all increments except the eighth increment which was below
normal when compared to the state averages. A desirable size structure exists
with over 60% of the yellow perch eight inches or larger in length, however
these fish may be unappealing to anglers as 67% had infestations of yellow
grub.

Walleye abundance as indexed by gill nets averaged 9.4 per lift and was near
the third quartile for this lake class. Walleye abundance was higher in 1999
than in the previous four surveys (1982, 1985, 1990, and 1995). Walleyes
ranged in the age from one through nine (110 of 141 aged) with strong
year-classes indicated the last four years (1995-1998) making up 86% of the
catch. The 1996-1998 year-classes were naturally produced in the lake. Growth
of walleyes as indicated by scale increments were normal until age five and
below the state averages thereafter. The PSD of walleyes was 18, which is low,
but similar to the last four surveys.

Black bullhead index increased in abundance from the 1994 survey (Wilcoxon
sign rank test, n=8, p=0.036) and was above the third quartile for this lake type.
The highest catch occurred in Davis Bay representing nearly 90% all black
bullheads captured.

Shorthead redhorse abundance was above the third quartile for this lake type
and higher than in the 1994 survey (Wilcoxon sign rank test, n=12, p=0.07).
Other species captured were bigmouth buffalo, brown bullhead, rock bass,
white sucker, and burbot.