PROGRESS IN BIOLOGICAL INQUIRIES, 1986 33 
mediate in growth rate and character ratios occur, the designation of 
the blue pike-perch of Lake Erie as a distinct species (Stizostedion 
glaucum Hubbs) does not appear to be warranted. The blue pike- 
perch of Lake Erie has, therefore, been reduced to subspecific stand- 
ing, S. vitreum glaucum Hubbs. The yellow pike-perch accordingly 
becomes the type subspecies, S. vitrewm vitreum (Mitchill). The 
so-called blue pike-perch of Lake Ontario cannot, according to avail- 
able information, be regarded as subspecifically identical with the 
Lake Erie form. Subsequent study may suggest the desirability of 
placing the Lake Ontario “blue” in a new, ‘and as yet undescribed, 
subspecies. 
Growth compensation was demonstrated for the Lake Erie pike- 
perches. Calculated lengths at the end of each year of life showed 
that the fish which were longest at the end of the first year of life 
were almost invariably the longest throughout hfe. But fish with 
larger growth increments during the first year of life had smaller 
growth increments during subsequent years of life, and vice versa. 
FOOD STUDIES 
During the course of the Lake Michigan chub-net investigation in 
the years 1930, 1931, and 1932, the stomachs of approximately 6,000 
lake trout (Cristivomer namaycush) and lawyers (Lota maculosa) 
were preserved. These fish were captured in experimental gill nets 
of five mesh sizes. A qualitative and volumetric analysis of the 
stomach contents was partially completed during 1936. ‘No conclu- 
sions can be drawn until the data have been tabulated and sum- 
marized but it appears that both trout and lawyers feed to a greater 
extent than popularly supposed upon small noncommercial! species. 
The results of this investigation will provide pertinent information 
on the following controversial questions: To what extent does the 
lake trout depend upon the chubs (Leucichthys spp.) for food? Is 
the intensive commercial fishery for chubs detrimental to the more 
valuable lake trout fishery through the reduction of the potential 
food supply of the trout? Is the lawyer, a fish of little commercial 
value, a serious food competitor of the lake trout? In addition 
the stomach contents will yield valuable data on the distribution of 
the smaller species of fishes which cannot be captured, at least in 
appreciable numbers, by any commercial fishing gear now employed. 
LAKE ERIE GILL NETS 
Considerable progress has been made in the compilation of data on 
the selectivity of gill-net meshes with respect to the yellow perch and 
blue pike of Lake Erie. The experimental fishing was carried on from 
September 1927 to December 1928. The results of this investigation 
are of particular interest at the present time (February 1937) since 
they may be the deciding factors in the disputes now being waged on 
Lake Erie concerning the proper size mesh to be legalized for gill nets 
employed in the catching of yellow perch and blue’ pike. 
The Great Lakes program continues to emphasize the practical 
phases of scientific research: i. e., the conservation of the fisheries. 
This has been made an urgent necessity by the fact that the more im- 
