22 REPORT OF THE COMMISSIONER OF FISHERIES. 



The Fish Hawk has been engaged in an exploration of Chesapeake 

 Bay to discover and record the seasonal conditions of salinites, tem- 

 peratures, currents, and ultimate food supply of fishes, and to ascer- 

 tain within the limits of feasibility all other conditions affecting 

 the migrations and abundance of fish and shellfish. All of these 

 data are essential for the most intelligent conservation and develop- 

 ment of the important fisheries of this bay. 



THE BIOLOGICAL LABORATORriiS. 



For the first time since the early part of 1917 the Bureau has had 

 the full possession of all of its laboratories; but, while available 

 for use, it has not been possible to operate all of them actively. 

 The Woods Hole (Mass.) laboratory was rather fully engaged dur- 

 ing the summer of 1919 with investigations in progress concerning 

 oysters, the reddening of salt fish, gelatin from seaweed, and the 

 habits, food, and parasites of fishes. 



The Beaufort (N. C.) laboratory could not be put in shape for 

 operation until late in the fiscal year, and deficiencies of funds and 

 of personnel have rendered the station relatively inactive. 



At the Fairport (Iowa) laboratoiy, studies of fresh- water mussels 

 and experimental fish culture were pursued, with the use of the 

 limited space afforded in the old temporary laboratory building. 

 During the year, however, the excellent new building, fireproof in 

 construction, pleasing in appearance, and admirable in design, was 

 brought nearly to completion and its occupancy was expected at an 

 early date in the following fiscal year. 



Progress in the construction of the Key West (Fla.) biological 

 station consisted principally in the installation of the necessary units 

 of the pumping system and the construction of a concrete tank tower 

 with storage for both fresh and salt waters. The water system is, 

 therefore, complete and ready for use, and this is one of the most 

 essential features of equipment of the station. The available labora- 

 tory space and other accommodations which it has been possible to 

 supply from the appropriations hitherto made are inadequate for 

 scientific work in the interest of the fisheries, except such as may be 

 rendered by the permanent staff authorized. The station functioned 

 usefully for a portion of the fiscal year, but since the loss of its 

 scientific staff, about the middle of the year, it has remained idle and 

 in the charge of a single employee as caretaker. 



Too cordial an acknowledgment can scarcely be made of the loyal 

 and devoted service of the men who have still remained in the service 

 during these times when the most trying economic conditions have 

 been and are yet bearing heavily upon them. The Bureau expresses 

 also its appreciation of the services of those who have rendered their 

 contribution to the work of the year, and left only under the com- 

 pelling pressure of circumstances. 



PROPAGATION AND DISTRIBUTION OF FOOD FISHES. 

 SUMMARY OF THE OPERATIONS. 



The output of the hatcheries during the fiscal j^ear 1920 fell short 

 of the results in 1919, when a record was established. The aggregate 



