FISHERY BULLETIN: VOL. 82, NO. 1 



TABLE 1. — Size frequency distribution of Artemia 

 nauplii measured by the Hiac Particle Counter (n = 

 1542) and by microscope (n = 45). 



FIGURE 3. — Map of the Austnesfjord with stations. • Juday net 

 and particle/zooplankton stations, position of the 24 h station -k, 

 and the Wolfe wind recorder i£r. 



about 20 larvae from each depth were examined by 

 dissecting the larval gut under the microscope. 



During 24-h stations in situ particle profiles, CTD 

 profiles, and zooplankton pump profiles were made 

 simultaneously every 2 h. On sections, zooplankton 

 pump profiles were made on every second station. 



RESULTS 

 In Situ Instrument Tests 



Results of the comparison between microscope and 

 particle counter measurements is presented in Table 



144 



1. A chi-square test for independence in the 4X2 

 table (3 df) showed no significant difference (P < 

 0.05) between the two methods of measuringArterata 

 nauplii. 



Paired tests between microscope and in situ parti- 

 cle counts were done on data from two different 24-h 

 stations in the Austnesfjord (Figs. 4, 5). Plankton 

 pump samples were taken from 11 different depths 

 on each profile, and the mean counts from these 

 depths were tested against the mean in situ counts 

 from the same depths. A comparison was also made 

 between the mean of all plankton pump counts from 

 each profile, and the mean of all in situ counts from 

 the corresponding profile. 



During the first 24-h station, 19 vertical profiles 

 were made. No significant differences (P < 0.05) was 

 found when the mean counts (n = 19) from each of 1 1 

 different depths were compared, nor when the mean 

 counts from the different profiles were compared. 

 The same statistical test was made on data from 14 

 vertical profiles on the second 24-h station. There 

 had been an increase in the variability of mi- 

 crozooplankton both horizontally and vertically dur- 

 ing this 24-h station (Fig. 5A, B). No significant 

 differences (P < 0.05) was found between the mean 

 in situ counts and the mean plankton pump counts 

 when the different profiles were tested. We found, 

 however, a significant difference (P < 0.05) when the 

 mean counts from corresponding depths were tested. 

 This difference was found between in situ and 

 plankton pump counts both from 30 and 40 m 

 depths. No significant difference (P < 0.05) was 

 found between counts from 0, 0.5, 7.5, 10, 12.5, 15, 

 20, and 25 m depths. This difference may have 

 resulted from samples having been taken at different 

 depths. The in situ instrument was equipped with a 

 depth detector, but the depth of the submersible 

 pump was controlled only by the meter wheel on 

 the winch. 



Distribution of Particle/Nauplii 

 in the Fjord 



The vertical distribution of particles/nauplii for a 

 24-h station made during 22-24 April 1981 in the 



