282 BULLETIN OF THE BUREAU OF FISHERIES. 
ficially hatched mackerel. When naturally hatched mackerel are first observed 
they are at least 3 or 4 inches long, and menhaden have never been seen under 1 
inch in length. 
Eggs that are stationary or agglutinated, if they are from a single parent and 
all subject to the same conditions, will hatch at approximately the same time 
and produce fish of comparatively uniform size. Aggregations of floating eggs 
are likely to be derived from several parents, laid at somewhat different 
times, and consequently will produce young of somewhat more diverse sizes. In 
both instances the rate of growth of individuals varies, causing a difference in 
size, but on the whole each school of young fish is composed of individuals of 
fairly uniform sizes. This uniformity appears to be to a great extent perma- 
nently maintained; yet it not infrequently happens that schools of two or 
more sizes become mixed, especially when a school is first broken up by any 
means and the scattered fish subsequently join other schools. 
Whether the schooling habit of the early stage is retained and is the basis 
of the schools of larger sizes up to adults is impossible to say. That such is the 
case is indicated by the comparative uniformity in size of individuals of schools 
of larger fish. Sometimes, however, a school is so large that it could hardly be 
the original brood or aggregation only, but several, or perhaps many, broods. 
But such a ‘‘raft” is composed of individuals of comparatively uniform sizes, or 
of sizes suggesting that the fish are of about the same age. 
The occurrence of such extensive ‘‘rafts”’ or “‘ bodies” of uniformly sized fish 
in the spring of the year suggests that possibly the younger fish have a somewhat 
different habitat from the older ones at that season of the year when they are 
beyond observation—that is, after they have ‘“‘left the coast” and prior to their 
“return.”” But, as mentioned in the case of young fish, accidentally mixed 
schools of older fish of the same species, as well as schools containing unre- 
lated species, are not uncommon. Mixed schools of large and smaller fish, or 
schools containing adventitious species, are likely to occur when the schools 
have been broken up and driven about by predaceous animals or by purse- 
seiners. Such broken-up schools or straggling individuals, or even small schools, 
are prone to fall into the procession when a larger body of fish happens along, 
even though it is of a widely different species, if it is not inimical. Another 
possible cause of mingling is when the fish are feeding upon the same kind of 
food and the food happens for any reason to be bunched. 
INADEQUACY OF AVAILABLE INFORMATION. 
Since the History of the American Menhaden, in 1877, and a brief 
summary of that work in 1884, also by G. Brown Goode, there has been little 
published regarding the habits of this fish. This history is remarkably compre- 
hensive, there being hardly a point regarding the menhaden that is not treated 
more or less exhaustively. The work was, however, an enlargement of manu- 
