BIOLOGY OF THE ATLANTIC MACKEREL 



177 



and 1927 when several samples were secured by dip net early in summer. 11 Their 

 lengths (table 21) agree closely with the terminal position of the growth curves de- 

 scribed by the chosen homologies, and are far below a growth curve predicated on 

 the alternatives. Hence it may be concluded that the chosen series consist of truly 



O 



0.6 0.8 1.0 1.2 



LOG OF LENGTH, MM. 



1.4 



1.6 



_1 L_1_L 



10 15 



LENGTH, MM. 



20 



30 40 50 



Figure 7. — Growth or mackerel larvae and post-larvae as indicated by the progress of modes in the deviations of numbers of speci- 

 mens in each size-class taken on individual cruises from the average number taken on all cruises. The letters R, S, and T mark 

 the positions of homologous modes referred to the scale of dates; and the straight lines are fitted to the homologous series. The 

 vertical interior scale is the scale of deviations in logarithms. Roman numerals are cruise numbers. 



homologous modes, and that the straight lines fitted to the respective series correctly 

 describe the larval and post-larval growth in 1932. 



» Schools of very small mackerel wander into pound-nets from which they can be removed by dip net if the pound-nets are 

 visited before hauling. Once hauling commences they are frightened and usually escape through the meshes. In addition tu 

 samples so collected, [one was taken from a school which wandered into the boat basin at the U. 8. Fisheries Biological Station, 

 Woods Hole. 



[library 



