TILSETH and ELLERTSEN: FOOD ORGANISMS OF LARVAL COD 



80- 



a. 

 

 q 50 



>150 



20- 



40 



r~ft~^~ Particle density 

 \C- 150 nos. per liter 



' 100 



40 



fe\ 40 30 l^^ x 20 7 rO C/ 20 





60 



FIGURE 9. — Wind velocity (length of vector, see m/s scale) and direction from the abcissa (A), 

 isopleth diagrams of temperature (B), and particle concentration (300-500 yum) distribution (C), 

 at the middle station on section 5 in Austnesfjord, 9-15 May 1980. 



90-100% .The larval feeding ratio was >1 prey/larval 

 gut in all samples taken before midnight. In 71% of 

 these samples the feeding ratio was >2 prey/larval 

 gut and in 14% of the samples >3 prey/larval gut. In 

 samples taken after midnight, however, the feeding 

 incidence varied between 4 and 92%. The lowest 

 level was found in pump samples from 25 m depth 

 from the 01-02 h profile. In 38% of the samples taken 

 after midnight the feeding incidence was <50%. Only 

 in the last pump profile made at 09-10 h the larval 

 feeding incidence was more than 50% in all samples. 

 The feeding ratio was < 1 prey/larval gut in all sam- 

 ples from 01-02 h profile, and <1 prey/larval gut in 

 61% of all samples taken after midnight. A feeding 

 ratio level <1 prey/larval gut was not observed in 

 samples taken before midnight. The highest feeding 

 ratio observed in samples taken after midnight was 



1.65 prey/larval gut from the 25 m depth samples 

 taken from the 09-10 h pump profile. 



Distribution of Particles/Nauplii 

 in Open Ocean Waters 



The main first feeding area of the Arcto-Norwegian 

 cod is thought to be the waters outside the Lofoten 

 islands and in the open ocean bay of the Vesterals- 

 fjord (unpubl. data). Figure 12A and B shows the 

 particle and nauplii distributions in the northeast 

 section in the Vesteralsfjord. Plankton pump samples 

 were only taken at every second station on the sec- 

 tion. The figure shows a similar distribution pattern. 

 However, due to the more frequent samples taken by 

 the particle counter, a more accurate distribution 

 picture of the particles on the section was achieved. 



149 



