662 U. S. BUREAU OF FISHERIES 
blackfin, or the Erie herring, could ever have become exterminated with the 
employment of as large a mesh as was used to take them. 
Theoretically, it should be quite all right to carry on a fishery that takes 
only the largest fish, especially when those fish already have spawned several 
times before their capture. We have indications that there is a delicate balance 
in the economy of gregarious species, which is adversely affected by great 
reduction in their numbers. 
Besides “catching out” the fish, the waters in many once very productive 
areas have been made unfit for fish by the increased dumping of pollution from 
industrial sources. It almost comes to the condition that the fishermen some- 
times charge that the fish are bound to be poisoned, anyway, and they might 
as well catch them as soon as possible. 
As discouraging as it is that the fish are being exterminated and the waters 
polluted (and here I want to repeat that I am not an alarmist; the facts are 
plain and point to an unavoidable conclusion), it is demoralizing to realize that 
nothing is being done about it. No less than nine governments are administer- 
ing conservation legislation, and it goes without saying that no two have the 
same idea! Some, in fact, have no idea at all! Control of these fisheries must 
be coordinated, and this clearly is possible only through a centralized body. 
As the waters are international, this body must be international in character. 
The problems that confront other fisheries, confront the conservationist on 
the Great Lakes—we want to know more about the life histories of our species ; 
we want to know whether artificial propagation does any good; we want 
adequate statistics; in short, we want to know everything about them, but, 
most of all, we want regulation of the quality and the quantity of the apparatus, 
or no fish will remain for us to investigate. 
LIFE HISTORIES OF THE COREGONINA 
By Dr. JoHN VAN OOSTEN 
When the life-history studies of the coregonines of the Great Lakes were 
begun in 1921 the scale method of study had not been applied to these species 
of fish. Since then two short preliminary papers haye appeared—one on the 
whitefish of Lake Erie and one on the herring of that lake—in which the 
scale method was employed. During the past six years I have accumulated 
many data on, and a large amount of scale material of, the lake herring, white- 
fish, blackfin, and several species of chubs. The chubs have been studied little. 
The work has been confined chiefly to the lake herring and to the whitefish of 
Lake Huron. ; 
The problem, as I saw it at the beginning of the study on the lake herring, 
involved three questions: 1. Are the structural characters of the herring scales 
so clearly recognizable as to permit their study by the scale method? 2. If 
the characters are thus recognizable, are the fundamental assumptions under- 
lying the scale method warranted in the lake herring? 3. If the scale method 
is valid, what does its application to the lake herring show concerning its life 
history and the fishery of it? 
It is apparent at once, to those who are familiar with scale work, that the 
scope of the above problem is very broad indeed. I am convinced, however, 
that such a broad scope was entirely warranted. Too many life-history papers, 
based on the scale method, are written without any regard to the validity of 
the method, in so far as the particular species involved is concerned. It is 
repeatedly asserted by scale investigators that assumptions that are valid for 
one species are not necessarily valid for others. Further, for no one species 
of fish have all the assumptions of the scale method been verified, nor have 
these assumptions been tested critically in the wild, fresh-water fishes of this 
country. Most of the theoretical work has been done on the marine fishes— 
salmon, herring, and plaice. 
The major assumptions whose validity was considered in my studies involved 
the constancy in the number and the identity of the scales throughout life, the 
growth relations between the scales and the body, and the relation between 
the formation of the annuli and the increments of time. Nearly 4,000 speci- 
mens, collected at the same place for four consecutive years, were employed 
for this study. 
The various phases of the scale theory can not be considered at this time, 
but I would like to mention briefly two of my conclusions which affect the 
scale method as it is generally applied to-day. First, my data show that the 
