Fishery bulletin of the Fish and Wildlife Service - NOAA

352 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE
were in the same interval (81-90 feet). The strongest indication of two concentration
zones of illegal fish is found in the scanty September data. Young whitefish were much
scarcer in the shallower water of the .Saginaw Bay area than at corresponding depths
on the Alpena-Ossineke grounds.
HARBOR BEACH GROUNDS
The observations of 55 lifts of deep trap nets off Harbor Beach (no pound nets
were observed here) were all made in the latter part of the 1932 season (table 26),
when on the basis of the preceding data the whitefish would be expected to be concentrated
in the deeper water. Actually here is where the deep trap nets were found
in operation. Fifty of the lifts were made from depths greater than 90 feet. Consequently,
no detailed description of the vertical distribution of whitefish at all depths
in this area is possible. The maximum concentration of both legal and illegal whitefish
occurred in the 101-110 foot interval in all three months. In the season's average the
number of legal fish per lift was greater at 91-100 feet than in waters deeper than 110
feet, but the reverse relationship was found in the data for illegal whitefish. The single
shallow-water lift (41-60 feet) contained no whitefish. The legal whitefish were more
abundant than the illegal fish at all depths.
Au st
October
Au t
September
October
TABLE 26.—Number of legal and illegal whitefish per lift of deep trap nets off Harbor Beach, 1932
[Number of lifts in parentheses. Asterisks indicate concentrations]
Month
Month
41-60
( 0.0
\ U)
/ 00
1 (1)
41-60
( 0.0
t (D
/ 0.0
\ (1)
61-70 71-80
61-70
===
Number of legal whitefish per lift at depth fin feet)
101.0
(1)
101.0
(1)
81-90
42.0
(3)
42.0
(3)
91-100
f 251.0
i (D
270.5
(8)
J 62.5
i (2)
231.5
(11)
101-110
420.5«
(2)
291.7*
(12)
117.3*
(3)
276.1*
(17)
Number of illegal whitefish per lift at depth (in feet)
71-80
65.0
(D
65 0
(1)
81-90
33.3
(3)
33.3
(3)
91-100
/ 150.0
i (D
73.2
(8)
f 32.0
\ (2)
72.7
(И)
101-110
298.0*-
(2)
167.2*
(12)
67.7*
(3)
165.0*
(17)
111-120
408.3
(4)
134.2
(6)
34.5
(2)
208.9
(12)
111-120
266 '. a
(4)
67.7
(6)
32.0
(2)
128.1 '•
(12)
BATHYMETRIC DISTRIBUTION OF WHITEFISH IN LAKE MICHIGAN
GREEN BAY AREA (MARINETTE, ESCANABA, AND FAIRPORT)
The 30 lifts of pound nets and deep trap nets observed in the Green Bay area do
not offer adequate information on the bathymétrie distribution of the whitefish at any
one time or on the seasonal movements of whitefish. The data of table 27, however,
indicate rather clearly that legal whitefish in this region were in deeper water in September
(61-^80 feet) than in May (60 feet and less). Illegal whitefish were relatively
numerous in May at depths less than 61 feet, and were present in large numbers also in
the two lifts from the 81-90 foot interval. Few illegal whitefish were taken at any
depth in September.
>12Û
135 8
(5)
163.0
(3)
46.0
(2)
Í2ÍÕ
(10)
>120
79.0
(5)
75.3
(3)
55.5
(2)
73.2
(10)