FISHERY BULLETIN: VOL. 70, NO. 3 



catches in the South Atlantic Area and were 

 most similar in size to catches made 1 to 3 months 

 earlier from school-aggregations off Long Island 

 (Table 2). 



In summary, the data presented demonstrate 

 heterogeneity in the seasonal and areal grouping 

 of Atlantic menhaden. Two basic groupings are 

 evident: (1) summer schools, which are vari- 

 able in size, comprised of discrete and indepen- 

 dent clusters of fish, and differentially distribu- 

 ted over the range of the species, and (2) fall 

 school-aggregations, which are large, but of 

 undetermined size, and found only along their 

 apparent southward migration route. 



Questions immediately arise concerning the 

 grouping of the fish following their disap- 

 pearance off North Carolina through the time 

 of their return northward migration in early 

 spring. During this roughly 3-month period 

 they are usually not seen at the surface. The 

 spring movement seems to be largely over by 

 the time that summer schools reappear in the 

 inshore surface waters and become available to 

 the purse-seine fishery. Inspection of first-of- 

 the-season single-school catches suggested that 

 some of these were larger than those taken im- 

 mediately afterward, but the numbers of such 

 catches were too few in most years to test this 

 hypothesis statistically. Table 3, for example, 

 gives available data on single-school catches dur- 

 ing the first week of fishing in each major area 

 (cf . Table 1 ) . A plot of school size on time, how- 

 ever, indicated no clear relationship and in most 

 years was similar to that shown in Figure 4. 

 Thus, elucidation of the off -fishing season group- 

 ing of the fish awaits further study. 



LENGTH OF FISH WITHIN 

 AND BETWEEN GROUPINGS 



There was a tendency for fish within summer 

 schools to be of similar lengths, although the dif- 

 ference between the largest and smallest indi- 



Tso 



tn OK _ 



25 - 



Moy 



July 



Aug 



Sept 



Figure 4. — Size of 462 single-school summer purse-seine 

 catches of Atlantic menhaden in the four major statisti- 

 cal areas in 1959 plotted against time. 



Table 3. — Size of single-school purse-seine catches of Atlantic menhaden made during the first week of the fishing 



season in the four major statistical areas, 1955-62. 



704 



