Vol. 53 - Alaska Resources Library and Information Services

Methods for analysis of depth distribution patterns are discussed in
Section 2.8.
Results of that analysis and examination for potential
vertical migrations are discussed here.
4.6.1 General Patterns
The vertical distribution of zoeae from 1980 and 1981 MOCNESS
samples is shown in Fig. 4.6.
C. bairdi and C. opilio zoeae show similar
depth distributions, with more than 95% of the larvae occurring in
the upper 40 m and 80% or more occurring in the upper 20 m.
For all data collected after 11 May in 1981, the depth distribution
pattern for SI and SII zoeae combined was virtually the same as in 1980
for SI.
Only prior to 12 May 1981 and only for C. bairdi zoeae was
there a significant departure from this pattern (Figure 4.7).
The
pattern seen for this species before 12 May is primarily the result of
four separate tows taken approximately six hours apart at a single
station during a 24-hour period on 11 May.
A comparison of the vertical distribution of SI and SII zoeae made
in two ways showed no significant difference in distribution between the
two stages.
First, data were considered only from stations where both
SI and SII zoeae occurred (8 stations sampled during 1981).
The results
are shown in Figure 4.8.
Second, all data for SI zoeae (15 stations)
and all data for SII zoeae (24 stations) during 1981 were tabulated
separately. Again, similar patterns of distribution for the two stages
were indicated; overall, 92% and 93% of SI and SII animals, respectively,
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