Vol. 53 - Alaska Resources Library and Information Services

not to subsample depended on the size of the sample and required some
subjective judgment.
The general rules governing this decision follow:
1. Subsampling was done only if the settled volume of zooplankton
in a clean sample exceeded approximately 0.15 1.
The desired
settled volume of a clean sample from which decapod larvae
would be removed was approximately half the above, or 75
ml.
A Folsom plankton splitter was used to split samples.
2. Subsampling was not done if the original sample contained a
large volume of gelatinous zooplankton or aggregating phytoplankton
(e.g., palmelloid form of Phaeocyctis poucheti) which
interfered with the subsampling (splitting) process.
3. Subsampling was not done if the original sample contained a
large number of large organisms (euphausiids, chaetognaths,
etc.) but relatively few smaller animals.
4. A sample was not subdivided into a fraction containing less
than 1/80 (MOCNESS) or 1/16 (Bongo) of the original tow.
The above guidelines were followed to ensure that subsampling yielded
representative samples of the plankton.
The adequacy of this approach
was checked on several occasions with samples representing a variety of
plankton conditions.
These results are reported in the Data Sensitivity
and Accuracy section that follows.
In all cases where at least one split was possible, one of the
final pair of samples was archived for possible future needs, including
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