1Q8(3 U. S. BUREAU OF FISHERIES 



The 1929 field work was devoted almost entirely to the collecting of 

 biological and statistical data on the various species of commercial 

 importance at Erie, Pa.; Conneaut, Lorain, Vermilion, Huron, San- 

 dusky, and Port Clinton, Ohio. In all, some 49,819 measurements 

 were made and scales were collected from 27,097 specimens. These 

 data were obtained by H. J. Deason, B. H. Hill, and Dr. Stillman 

 Wright aided by four temporary assistants, the States of Ohio and 

 of Pennsvlvania each furnishing two men. 



An analysis of the blue pike, yellow pike, and sauger material of 

 1928 indicates that in each species the 3-year fish predominated.^ The 

 2-year group predominated in the yellow-pike material of 1927, sug- 

 gesting that in this species the 1926 year class was dominant m the 

 population. In addition to a study of the life history of these pike 

 perches, an attempt is being made to ascertain the systematic rela- 

 tionship between the blue pike, the yellow pike, and what appears to 

 be an intermediate form sometimes designated as the gray pike. For 

 this study adult pike perches of Lakes Ontario, Erie, and Huron are 

 being examined in addition to a large series of larval and postlarval 

 specimens kindly loaned to us bv the State of Ohio. 



Analvsis of the scales of the ciscoes taken in gill nets in 1927 shows 

 the catch to be comprised almost entirely of 2 and 3 year fish, while 

 the whitefish samples of 1927 taken in gill nets and trap nets con- 

 sisted principally of 4 and 6 year fish, the 5-year group being almost 

 entirely absent. 



The work in Lake Huron on the experimental herring pound nets, 

 referred to in the 1928 report, will not be completed until the spring 

 of 1930 but the data collected so far show the following : 



1. In the fall of 1928 no herring escaped through the larger meshes 

 of the net for each size group was represented in approximately the 

 same proportion in the catch of the various nets. (2 inches, 2i^ 

 inches, and 2% inches.) 



2. In the spring of 1929, however, some sorting seems to have taken 

 place for the percentage of small herring in the lifts decreased pro- 

 gressively with each successive increase in the size of the mesh em- 

 ployed. (2 inches, 21/0 inches, 2% inches, and 3 inches.) 



3. The number of herring that gilled before the fish were cornered 

 increased progressively with each increase in the size of the mesh 

 employed. 



4. Virtually no immature whitefish or yellow pickerel were gilled 

 in the experimental nets. 



The interesting inconsistency in the apparent reaction of the her- 

 ring to the different-sized meshes in the fall of 1928 and in the spring 

 of 1929 may possibly be explained on the basis that there were more 

 small herring on the grounds in the spring of 1929 than in the fall 

 of 1928 and, hence, the effectiveness of the nets in sorting would 

 appear to be greatest in 1929, or that since the data were secured 

 during the spawning season, the herring of 1928 were less aware of 

 their surroundings because of sexual excitation and exerted less effort 

 in escaping from the traps than those of 1929. 



In addition to the work on experimental pound nets, biological 

 data, such as length and weight measurements, sex, maturity, and 

 scales, were collected for the important species of Saginaw Bay, 

 especially the yellow pike, lake herring, and whitefish. Some 20,018 

 fish were measured and 5,176 scales were collected. 



