parison using the number of gill rakers on the 

 upper arm of the arch showed no significant 

 difference (table 8B) . 



For the 1954 year class, no significant 

 differences in total numbers of gill rakers were 

 found between upstream and downstream samples 

 from the York and James River Systems. This 

 involved a comparison between and I in both 

 cases (tables 9A and 9B). 



When total gill raker counts of and I 

 samples of the Rappahannock 1953 year class 

 were compared, t was found to be significant at 

 the 5 percent level (table lOA) . However, using 

 the counts of the upper arm there was no sig- 

 nificance (table lOB) . 



A t-test was also run on the samples of 

 the 1953 year class from the York River System. 

 Using the count on the upper arm there was no 

 significant difference between the Mattaponi 

 and the York I (table IOC), but when using the 

 total number of gill rakers, the difference 

 proved to be significant at the one percent level 

 (table 11 A). When a covariance was run to ad- 

 just the fish to a common standard length the F - 

 value was not significant (table 12). 



A comparison of Rappahannock and York 

 samples was made by use of a t - test for the 

 above data. For the total number of gill rakers 

 of the I specimens there was no significant 

 difference (table 11 B). By observation, the 

 mean of the Rappahannock (24.68) versus the 

 mean of the York (24.69) was not considered to 

 be significantly different for the age group 

 either. 



An analysis of variance of 0, I and II 

 age groups of the 1952 year class in the York 

 River System proved not significant (table 13) . 

 Also an analysis of variance was carried out for 

 the age group of the 1949 year class from 

 Crisfield, Maryland and there was no signifi- 

 cance (table 14). Samples of 5 year classes 

 (1949, 1952, 1953, 1954 and 1955) from the 

 James River were compared by an analysis of 

 variance. It was found that there was a signifi- 

 cant difference (table 15). 



The mean value of the gill raker count 

 on the first branchial arch and those from the 



upper arm of the same arch of samples of young 

 of the 1955 year class from 17 rivers were 

 ranked from the lowest to the highest under the 

 two categories. The resulting correlation co- 

 efficient (r = .806) indicates a good correlation. 



In summarizing the results given above, 

 a biological difference was considered to exist 

 only if the statistical differences were of a large 

 magnitude when using both the count on the upper 

 arm and the total number of gill rakers. The 

 results seem to indicate that several subpopula- 

 tions of striped bass exist in the Chesapeake Bay. 

 The first subpopulation is in the Upper Bay; this 

 includes the rivers north of the Rappahannock on 

 the west shore and all the east shore rivers 

 covered in this study . The Patuxent River sample 

 has a lower gill raker count than the other rivers 

 in the Upper Bay but perhaps this is not of bio- 

 logical significance and may be due to random 

 variation or other sampling procedures. How- 

 ever, until stronger evidence is presented that 

 the Patuxent River is biologically different, it 

 should be considered as belonging to the homo- 

 geneous subpopulation from the Upper Chesapeake 

 Bay. 



The Rappahannock and York striped bas^, 

 belong to another subpopulation, while the Jameb 

 is the third subpopulation. There doesn't seem 

 to be any upstream - downstream difference in 

 any of the rivers that can be deemed biologic illy 

 significant . 



Enough statistical difference exists among 

 year classes from the same locality so that it 

 seems unwise to lump year classes in making 

 comparisons between localities. Study of addi- 

 tional year classes from throughout the Chesa- 

 peake Bay region may modify these conclusions . 



Comparison of populations above and 

 below Pinopolis Dam, South Carolina . --A uniq ;e 

 situation exists in the Santee-Cooper Reservoir 

 System of South Carolina . With the completion 

 of Pinopolis Dam in 1942, water was impounded 

 in Lake Moultrie and Lake Marion. This pro- 

 vided a fairly effective separation for striped 

 bass above and below the dam . Scruggs and 

 Fuller (1955) found that there is slight recruit- 

 ment of fish from the Cooper River to the reser- 

 voir population during the operation of the locks; 

 they also found that adequate spawning occurred 

 above and below the dam . 



