REPORT OF COMMISSIONER OF FISH AND FISHERIES. 
XV 
tion will be obtained to permit of a full understanding of tlie situation 
by the next Congress. 
The daily observations of temperature along the sea-coasts and on 
the interior lakes and rivers, begun several years ago, have been con- 
tinued during the past year at a number of the more exposed light- 
houses and at many stations of the Signal Service. The value of such 
observations will readily be appreciated by the student of geographical 
distribution, and a comparison of the results now in progress of com- 
pilation will undoubtedly throw much light on the movements of our 
migratory fishes. 
The temperature data heretofore obtained serve only to show the 
temperature fluctuations* in the waters immediately adjacent to the 
coast. The deductions from these have been sufficient to show that 
the movements of the fishes in the inshore waters, their appearance 
and departure, and their failure to appear in certain seasons in certain 
localities are to be attributed to differences of temperature conditions 
prevailing at different times. Observation and experience have sug- 
gested that the seasonal migrations and distribution in our coastal 
waters of mauy important economic fishes is to be explained and indeed 
to be predicted when we can obtain precise knowledge of the daws 
governing the seasonal changes of temperature in the area of water 
lying between our coast and the western border of the Gulf Stream. 
The migration of the areas of equal water temperature will be different 
in the different seasons and determine corresponding differences in the 
areas over which fishing may be profitably pursued. 
It will, however, doubtless be found that the seasonal migrations of 
the areas of equal temperature in the sea will be in close and essential 
relations with the meteorological conditions on the land, which are 
under constant observation and discussion, and in time a knowledge of 
one will enable us to interpret the other, and thus indicate the probable 
distribution for the season of such species as the macke^l, the menha- 
den, the sea herring, and others which are pursued for their commercial 
value. Such information would relieve many perplexities and embar- 
rassments which now discourage our fishermen, and give better direc- 
tion to their enterprise and consequently better assurance of success in 
their endeavors. The investigations proposed and the discussion of the 
data obtained would doubtless lead to many important generalizations 
on the physical geography of the sea and the relations of marine species 
to their physical environments. 
Being impressed with the importance of a systematic study of the 
temperature conditions and the changes of conditions in our offshore 
waters, I have instituted a systematic investigation to this end and 
have assigned the Fish Commission schooner Grampus to this work. 
Prof. William Libbey, of Princeton College, has been selected to take 
charge of the investigation, and the vessel is now being fitted with the 
necessary apparatus and appliances for the work, and will enter upon 
it at the beginning of the next fiscal year. 
