90 REPORT OF THE SECRETARY OF COMMERCE 



Ichthyological studies of the South Atlantic and Gulf coasts have 

 included a continuation of taxonomical examinations and revisions of 

 the flounders, gobies, cyprinodonts, and other species. The fresh- 

 water fishes of the State of Mississippi also were studied and a report 

 was submitted to the recently established State game and fish com- 

 mission as an aid in formulating more effective laws of conservation. 

 The ichthyological studies included, also, a survey of the fresh-water 

 streams and lakes of Puerto Rico, carried on in cooperation with the 

 Insular Department of Agriculture and Commerce, the object of the 

 investigation being the determination of the present status of the fish- 

 eries and the possibilities of future cultural operations either of 

 indigenous or introduced species. 



FISHERY INVESTIGATIONS IN INTERIOR WATERS 



Owing to the severe curtailment of funds all field work has been 

 discontinued on the Great Lakes, and the staff has devoted its full 

 time to the analysis of the many fisheries data that have been col- 

 lected during the past years but which have not yet been compiled 

 in final form for publication. One important phase of the work 

 that is showing promising results is the detailed study of the sta- 

 tistics of the commercial fisheries of Lake Huron for the 5-year 

 period 1929-33. This study has made available not only complete 

 data on fluctuations in the total fishing intensity and in the yield 

 of each commercial species for each of the 6 statistical districts into 

 which Lake Huron has been divided but includes also a precise 

 tabulation of the fishing effort actually exerted for the capture of 

 each of the 8 most important species of the commercial catch. This 

 tabulation of fishing effort for each individual species (necessary 

 since identical types of gear are employed in completely distinct 

 fisheries), together with the elimination of the effect of the different 

 fishing times (nights out) of the same types of gear in different 

 geographical regions, has made possible an accurate determination 

 of fluctuations in abundance, as measured in terms of yield per unit 

 effort, not attainable through less refined methods of procedure. 

 The practical value of the methods employed has been demon- 

 strated clearly in the study of the rapid depletion of the stock that 

 has resulted from the use of the deep trap net for the capture of 

 whitefish. 



Another important phase of the Great Lakes work involves the 

 study of the life histories of the more important species of com- 

 mercial fishes. These studies on the three species of pike perches 

 (sauger, and yellow and blue pike perch) and the yellow perch are 

 rapidly nearing completion and preliminary reports have already 

 been published. On the basis of this work, recommendations are 

 made to the various State conservation departments on proper size 

 limits, closed season, size of mesh in nets, and other regulatory 

 measures. As a result of these studies it was also possible to submit 

 to the National Recovery Administration many basic data to show 

 the need of the inclusion of certain uniform conservation measures 

 in the Great Lakes Fisheries Code. 



A manuscript was recently completed for publication on the age 

 and growth of the cisco of certain inlaml lakes of northeastern 

 Wisconsin, a study made possible by the cooperation of the AViscon- 

 sin Geological and Natural Historv Survev. 



