Fishery bulletin of the Fish and Wildlife Service - NOAA

324 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE
these two northern districts the maximum productions were 263 and 317 percent,
respectively, of the 1929 yield. In central Lake Huron the maxima were 476 percent
in H-3 and 431 percent in H-4. It was in southern Lake Huron, however, that the
greatest relative increases in production occurred. The maximum yield was more than
26 times the 1929 catch in H-5 and more than 15 times, the 1929 production in H-6.
The differences in the relative maximum yields attained in the several districts
are to be attributed primarily to differences in the relative increases in fishing intensity.
The maximum intensity in H-l and H-2 was a little more than twice that of 1929.
It was roughly 5 times the 1929 level of intensity in H-3 and 4 times in H-4. In H-5
and H-6, however, the maximum fishing intensities were, respectively, 42 and 27 times
the 1929 intensity.
The relative maximum abundance attained in the various districts exhibited remarkable
agreement. In four of the six districts (H-l, H-4, H-5, and H-6) the
maximum abundance was between 140 and 150 percent of the abundance in 1929,
and in a fifth (H-2) the maximum was a little less than 140 percent (136 percent) of
the 1929 level. In H-3 the greatest estimated abundance occurred in 1929 in which
year the pound nets were particularly successful (table 11). The abundance in H-3
fell in 1930 but increased in 1931; peculiarly enough the abundance in 1931 was 143
percent of that in 1930 (cf. increases in other districts over 1929 abundance).
Production and abundance in 1939 were below the 1929 level in every district,
and the fishing intensity was less than that of 1929 in all but the two southernmost
districts. Of especial significance is the fact that the abundance in 1939 was relatively
much higher in H-l and H-2, the two districts in which production and
intensity had reached the relatively lowest maxima. In the remainder of the lake the
whitefish had almost disappeared. So great was the depletion that in H-5 and H-6
T/ABLE 7.—Maximum and Í9S9 production and abundance of whitefish and maximum and 1939 fishing
intensity for whitefish expressed as percentages of the 19e9 values in each statistical district of Lake
Huron •
H-l
H-2'
H-3
H-4
H-5
H-e
District
Year of
maximum
production
1931
1930
1931
1932
1933
1934
Production
Maximum
263
317
476
431
2,662
1,517
1939
38
23 15
19
46
Year of
intensity
1931
1930
1931
1932
1933
1935
Maximum
Intensity
233
228
528
377
4,211
2,678
1939
89
50 5
60
433
489
Year of
maximum •
abundance
1930
1930
182»
1931
1931
1932
Abundance
Maximum
1 The deep-trap-net fishery of 1929 «as excluded in the computation« of these percentage« of production and fishing intensity for H-2.
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FIOUM S.—îlrst district, H-l.
140
136
100
149
142
148
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Figures 5 to 10 «bow the annual fluctuations in the production («olid lines) and abundance (long dashes) of whitefish and in the intensity of
the whitefish fishery (short dashes) over the period, 1929-1939, in each of the six statistical district« of Lake Huron (see fig. 4). In euh figure the
central horizontal line represents the average conditions for the 11 years, 1929-1939.
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O
1939
41
43 в75
10