They represent species of the
small fish and any other prey of proper size.
In the remainder of this report, common names rather
fifth trophic level.
than scientific names will be used for convenience.
SAMPLE PROCESSING AND ANALYSIS
Sample processing and analysis began with counting and partially thawing
the fish from each location.
was recorded.
The total weight, length, and sex of each fish
tissue,
into muscle
Each fish was dissected
bone (cranial,
thoracic, vertebrae, ribs, pelvic and pectoral girdle), skin and scales (fins
discarded),
stomach
(gizzard)
contents,
liver,
and
remaining viscera that
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generally included large and small intestines with contents, stomach wall,
spleen, kidney, and mesenteries.
The concentrations determined in the viscera
samples are regrettably less descriptive than those for other tissues because
of the matrix of organs and tissues represented.
In some instances, however,
a finer division of the visceral components was made.
organ of the species from the same catch was pooled.
Each separate tissue and
It was necessary to pool
tissues from a particular catch for analysis because of the low concentrations
of transuranic radionuclides anticipated in
edible muscle
tissue.
This
resulted in the mixing of fish from several populations (weight classes) and
of different sexes.
Because mixing masked any differences in concentration
related to weight (size), sorting of different size classes for processing was
accomplished, in some instances, to assess the relationship of radionuclide
concentration with weight.
We were unable to relate any differences in
concentrations of specific radionuclides with sex.
the fish but not analyzed.
Gills were separated from
Our experience at Bikini and Enewetak Atolls
showed that gills were frequently contaminated with sediment.
Gills are not
eaten and questionable information would be gained from their analysis because
of the possible contamination.
After the wet weight was determined, each pooled fish tissue sample was
dried in ovens at 90°C to constant dry weight and ashed in muffle furnaces at
450°C.
The only samples
analyzed for ¢!0po9,
not prepared in this way were the samples to be
In those cases, wet tissues and organs were used.
.
The scientific objectives for the analysis of fish in the Marshall Island
Program changed over the years. For example, initially fish were collected to
assess the concentration of radionuclides in tissues of different species. of
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