GROVER and OLLA: EFFECTS OF EL NINO ON SABLEFISH FOOD HABITS 



1980 FISH SIZE 



12.6- 20.5 mm 



UJ 



o 



LxJ 



(T 



cr 



O 



o 

 o 



U- 



o 



>- 

 o 



UJ 



3 



o 

 u 

 cr 



<l2.5mm 



7, VOL %N 



80 40 40 80 



°|~ I I — \ — rzr-| — I — I — I — I 



100 



200 



300 



400 



5001- 



80 



%VOL 

 40 



%N 

 40 80 





I I I I 



B 



F 



■H 



-I 



J 



20.6-28.5 mm 



%V0L %N 



40 40 80 

 I I I I 



1983 



UJ 



o 



z 



LU 



cc 

 a: 



O 



o 

 o 



>- 

 o 



UJ 



O 



UJ 



cr 

 u_ 



7, VOL 

 80 40 



100- 



200 



300 



400 



500 



7. N 

 40 80 



'AidJB-' ' ' ' 



A- INVERTEBRATE EGGS 

 B-PTEROPODS 

 C-COPEPOD NAUPLIl 

 L D-COPEPODS <lmm 

 E-COPEPODS i-2mm 



7.N 

 40 80 



%V0L 7,N 



40 40 80 



1 — \ — rn 



iX 



B 



F-COPEPODS >2mm 

 G-AMPHIPODS 

 H-EUPHAUSID LARVAE 

 I-APPENDICULARIANS 

 J-OTHER 



1 



I 



H 



-I 



Figure 2.— Relative importance of prey items in the diet of larval sablefish, by size class and year, 

 expressed as numerical percent composition {%N), volumetric percent composition (%VOL), and per- 

 cent frequency of occurrence (%F0). The area of each block represents the Index of Relative Impor- 

 tance (IRI) of a given prey (IRI = (%N + %VOL) x %F0). Sample sizes are as listed in Table 1. 



Comparisons with other years revealed that ther- 

 mal patterns off Oregon and Washington were 

 similar for 1980 through 1982 and 1984 through 

 1986 (fn. 4). In contrast, 1983 was markedly differ- 



ent, being the only year among those compared 

 when a 13°C isotherm developed and when surface 

 temperatures <10°C were not found between the 

 coast and long. 130°W during the first week in May. 



75 



