FISHERY BULLETIN: VOL. 74, NO. 4 



11 6 8 10 12 14 15 6 16 



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ORT 



' ^-L-^S^k^^ 



o 



NIGHT 



"-m — 



CD 



MOON 



I 



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1000 

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6 8 10 12 14 

 CPRPPRCE LENGTH (MHI 



16 8 16 

 NO. PER 10= m3 



Figure 1. -Vertical distribution of Sergestes atlanticus. 



whether the bulk of the population normally occurs 

 so shallow. A number of night tows in the 75- to 

 150-m range took small numbers of 5. atlanticus, 

 and one tow at about 250 m captured five in- 

 dividuals. There appeared to be no significant 

 variation of depth with size. Tows on moonlit 

 nights took small numbers of S. atlanticus from 

 the surface to about 350 m, with a possible con- 

 centration around 150-175 m. Several captures 

 were made between 600 and 925 m, suggesting 

 that at least part of the population did not always 

 migrate. The December 1970 cruise took substan- 

 tial numbers (up to seven) near full moon between 

 250 and 300 m, and also between 550 and 800 m, 

 indicating that only part of the population was 

 migrating. Later in the cruise when the moon was 

 waning, tows between 30 and 100 m took S. atlan- 

 ticus in moderate numbers (four to six). 



Population Size, Growth, and Reproduction (Figure 2) 



Sergestes atlanticus was moderately abundant, 

 turning up regularly in tows at the appropriate 



Table 3.-Estimated population sizes of Hawaiian sergestids from all horizontal tows and two series of oblique 



tows (no. per 100 m^). 



Teulhis XVIII 



TeuthisXXII 



Species 



(') 



(') 



Horizontal 



(') 



n 



Sergestes atlanticus 



Sergestes erectus 



Sergestes armatus 



Sergestes vigilax 



Sergestes orientalis 



Sergestes consobrinus 



Sergestes sargassi 



Sergestes pectinatus 



DD 

 DN 

 SN 



4.36 

 2.66 

 4.28 



3.66 

 1.31 

 3.09 



28 

 19 

 47 



DD 

 DN 

 SN 



1.17 

 1.10 

 0.28 



1.67 

 1.47 

 0.56 



D 

 N 



M 



2.10 

 0.84 

 0,46 



180 

 68 

 19 



1.71 



467 



806 



