SMILES and PEARCV : GROWTH RATE OF Eufhauna farifia 



4000 

 3000 

 2000 

 1000 



O 3000- 

 5 2000- 

 (t 1000 



g 3000 



2000 



1000 







1000 



I I I I I I I I I I I I I I I I I 



NH-15 



I I I I I I I I I I I I I I I I I I I I I I I H I I I I I I I 



10 o 



o oi— I oHo OOP 



OO P 



SlSL 



Us) 

 13.900 



NH-25 



o|— 10 0_0 



NH-45 



X\ 



r— lO I — I Q I — IQ Q 



□ 



Q 



.J3. 



TO Q^ 



27000 



_Q ^-~0 L. 



n 



Ql IQ 0. 



 Or- lO O- 



n^ 



1963 



1964 



oelUl |io| |i2| loil |04| ioeTloal fio] |i2 |o2| M W H MoMi^ lo^lW W M lio| jiF |oi| H M 



1965 



pa] [iol [IF |o2| |o4| 

 1966 1967 



Figure 1. — Number of furcilia of E. pacifica collected at four stations off Newport, Oregon (NH-15, 25, 45, 65) 

 during 1963-67. "0" indicates no sample taken for that month. 



• INSHORE {NH-15, NH-25) 



 ALL STATIONS 



▲ OFFSHORE (NH-65. NH-> 65) 



TOTAL LENGTH (mm) 



Figure 2. — Catch curves : the logarithm of the average 

 number of various sizes of E. pacifica caught per lO'^ m'^ 

 for all samples during the study. 



shore populations may be considerably higher 



than offshore populations in the same region. 



Although inshore tows were generally made 



only to 50 m and 130 m at the 15- and 25-mile 

 stations respectively because of depth of water, 

 euphausiid abundance at these stations was ap- 

 proximately 10 times greater than at offshore 

 stations. This difference is too great to be ex- 

 plained by the differences in sampling depths 

 even assuming that all euphausiids were con- 

 centrated in the upper 50 m at night. 



GROWTH RATE 



The extended spawning season and variability 

 of catches of E. pacifica made interpretation of 

 growth difficult. Three related methods, all 

 based on progressions of size-frequency histo- 

 grams, generally gave similar growth rates 

 (Table 1) and led to the same conclusion: E. 

 pacifica lives for a period of about 1 year and 

 attains a maximum size of about 22-24 mm total 

 length. We tenuously assumed for all these 

 analyses that we sampled the same population, 

 or populations with similar age structures and 

 growth rates. 



Two illustrations of growth based on monthly 



81 



