Vol. 53 - Alaska Resources Library and Information Services

techniques which attempt to equally sample all depths involved in the
tow (Smith and Richardson, 1977).
The MTD and MOCNESS nets had discrete
flow data for each depth interval sampled.
The only samples for which
flow data were not available are those from PROBES 1978; the average
flow (250 m³) computed for other processed zooplankton data from that
cruise was used.
Since every effort was made to keep those tows uniform,
the error introduced by this estimation is probably small compared
to real differences in decapod abundance.
The depth of sampling varied with the gear and cruise objectives.
The depth of Bongo tows from OCSEAP and NMFS cruises generally reflected
changes in the depth of water at various stations, whereas PROBES Bongo
tows usually sampled only the upper 60 m of water, even at the deeper
stations.
MOCNESS was operated to sample the following depth intervals:
1200-600, 600-300, 300-120, 120-80, 80-60, 60-40, 40-20 and 20-0 m (sometimes
20-10 and 10-0 m).
These depth intervals were modified slightly
or deleted as station depth or equipment malfunction dictated.
The MTD
net used to collect samples examined in this study was deployed at fixed
depths (e.g., 10 m, 30 m, etc.) rather than hauled obliquely through
larger depth intervals.
Samples were preserved in 3-5% formalin:seawater.
2.3 Sample Processing
Initial zooplankton samples obtained for this study varied from 20%
(our share of the MOCNESS samples) to 100% (most Bongo samples) of the
original tow.
This sample was then either examined entirely or was subsampled
before removal of decapod larvae.
The decision of whether or
508