PROGRESS IN BIOLOGICAL INQUIRIES. 13 



MOSQUITO CONTROL IN NORTHERN WATERS. 



While malaria is not prevalent in Northern States, the mosquito 



l^roblem persists and exerts its ill efl'ert upon property values, in- 

 dustrial productiveness, and personal etticiency. This was well illus- 

 trated when lar<re sums of money were expended in tlie effort to ex- 

 (erniinate mosquitoes in the \ icinity of a large shipyard. 



Prof. J. Percy Moore, of the University of Pennsylvania, as a tem- 

 porary investigator for the Bureau, has been charged with certain 

 experiments conducted in the vicinity of Philadel|)hi{L He has also 

 participated in investigations in the Palisades Interstate Park with 

 reference to the control of mosquitos by the use of fish and other 

 aquatic animals. A very gratifying degree of cooperation is ex- 

 tended b}' the officials of the park, and experiments have been started 

 which are proihicing results of scientific and practical interest. Im- 

 provement of the shore conditions around one of the principal ponds 

 of the park has already resulted in giving small fish better access to 

 shallow coves and little cut-off pools, and this in turn has effected 

 a material reduction in the abundance of mosquito larvae. Subse- 

 quent examinations of the stomachs of young fishes admitted to 

 such waters formerly teeming with mosquito larv£e have shown a 

 large proportion of mosquito eggs, larv£e, or pupae in the food. Other 

 experiments are in progress. 



This work is being done in connection with the cooperative investi- 

 gation between the Bureau of Fisheries and the New York State Col- 

 lege of Forestry at Syracuse, having to do with the control of mos- 

 (juitoes, the elimination of blood-sucking leeches, and the develop- 

 ment of the fish-cultural possibilities of the park. The general ob- 

 ject is to promote favorable conditions in the park for fishing, bath- 

 ing, and other forms of recreation. 



EXPERIMENTAL FISH CULTURE. 



Previous reports have stressed the need for fish-cultural experi- 

 ment work; yet this field of endeavor remains in a condition of de- 

 Aelopment that offers relatively small promise until circumstances 

 may be changed. This is not for lack of possibilities of service to 

 Government, State, and private fish culture, or for deficiency in 

 facilities ; the of)portunity is there, but the special personnel is want- 

 ing. Fish-cultural work demands the service of specialists — those 

 who can study systematically and continuously the functions and re- 

 lations of plants, insects, Crustacea, bottom conditions, fertility, form 

 and depth of pond, etc., with reference to methods of fish culture and 

 the productiveness of fishponds. The most the Bureau has been able 

 to do during the year just closed has been to keep the flame of experi- 

 mental fish culture burning, with the hope that provision may yet be 

 made for its adequate conduct. 



Some further results of importance have been gained in the experi- 

 ments conducted at the Fisheries Biological Station, Fairport, Iowa, 

 with catfish, buffalofish, Ikiss, and sunfishes. Certain experiments are 

 under way to determine the value of the use of manure or commercial 

 fertilizers for increasing the fertility and productiveness of fishponds. 

 Prof. C. B. Wilson at that station also continued his investigations 

 of aquatic insects in relation to fish culture in ponds. There are 



