Appendix Figure 1; Alaskan sites measure one by two 
degrees. Individuals from NMFS laboratories and af- 
filiated agencies involved in fish collection (Appendix 
Table 1) in each of these areas, were asked to collect 
designated species of fish and shellfish. Most of the 167 
requested species, genera, or families were collected. The 
original list was augmented by additional species to give 
a final tally of 204 species. Collectors were provided a 
protocol for labeling, preparing, storing, and shipping 
fishes, as well as a supply of Fish Data Labels (Appen- 
dix Figure 2). 
Collectors were requested to supply enough fish of each 
assigned species to yield 10 2-lb samples of edible muscle 
(hereafter referred to as a group) from each of four sites 
within their area (40 samples per species per area). 
Fishes were frozen as soon as possible after capture and 
shipped under dry ice via air freight to the Utilization 
Research Division, Northwest and Alaska Fisheries Cen- 
ter,’ Seattle, Wash., from Pacific locations, or to the Col- 
lege Park Laboratory, Southeast Fisheries Center,’ Col- 
lege Park, Md., from Atlantic and Gulf of Mexico 
locations. Each fish was stored, as received, at —25°C 
until samples were prepared from them. 
Wherever possible, collectors were asked to provide the 
common and scientific names, sex, length, weight, age, 
and tissue or cut of the fish; the date, depth, and location 
(latitude and longitude and/or local name) of capture; 
the number of individual fish; and the name of the boat 
and captain or market, as appropriate, on the Fish Data 
Label. If not performed by the collector, individual fish 
were counted, weighed, and measured at College Park 
and Seattle; fish were also sexed at Seattle. 
Finfishes were received for sample preparation in 
various forms; whole, headed and gutted, headed only, 
gutted only, skinless fillets and chunks, with and without 
skin. Livers were included with about one-fourth of the 
finfishes. Some milt and roe were also received. Shell- 
fishes were received both whole and prepared; shrimps 
were whole or headed; lobsters and crabs were in the 
shell; oysters and abalone were shucked; clams were in 
the shell or shucked; squid and octopi were whole; most 
scallops were received as abductor muscle only. 
Sample Preparation 
Fish were thawed immediately prior to sample 
preparation and processed as rapidly as possible to 
minimize any possible moisture loss, decomposition, or 
contamination from the laboratory environment. Skin- 
less fillets or their closest equivalent were prepared from 
most finfishes. Some small species and juveniles of other 
species were ground whole or as otherwise received. 
Shrimps were headed, peeled, and, unless too small, 
deveined. Lobsters were prepared as body, claw, tail, leg, 
or a combination of claw and tail. Crabs were prepared as 
body, claw, or as a combination of the two parts. Clams 
*Formerly known as the Pacific Utilization Research Center. 
‘Formerly known as the Southeast Utilization Research Center. 
and oysters were shucked. Except in one case, abductor 
muscles of scallops were prepared. Squid and octopi were 
prepared whole or as mantle only. Most samples con- 
sisted of raw tissue, although lobsters and some crabs 
from the Pacific coast were cooked. Each sample was as- 
signed a laboratory reference number and thoroughly 
ground to provide a homogeneous mixture for analysis. 
From 1 to 10 subsamples of each sample were packed in 
polyethylene cups and stored at or below —25°C. 
Analytical Procedures 
All chemical analyses were performed under contract? 
by Omni Research, Inc., San German, Puerto Rico. The 
concentration levels of 15 elements were determined in 
each of approximately 15,000 sample cups, including 
controls and duplicates, by atomic absorption spec- 
trophotometry (AAS). Mercury was analyzed by a flame- 
less (cold vapor) method based on that described by 
Hatch and Ott (1968) and later applied to analysis of fish 
tissues (Uthe et al. 1970). Arsenic and selenium were 
analyzed as their hydrides following procedures based on 
the arsine generation method of Dalton and Malanoski 
(1971) and further adapted from a development of this 
method for analysis of As and Se in fish tissues (South- 
east Utilization Research Center 1975°). The samples 
were at first digested for As analysis by dry ashing 
methods (about 40% of the samples). For the remainder 
of the As and all of the Se analyses, samples were wet 
ashed. The remaining elements (Sb, Cd, Cr, Cu, Pb, Mn, 
Mo, Ni, Ag, Sn, V, and Zn) were analyzed by conven- 
tional flame AAS, with direct aspiration of a digested 
sample after appropriate dilution. For Sb, Mo, Sn, and V 
analyses, samples were dry ashed only. For the other 
eight elements, approximately the first third of the 
15,000 sample cups were analyzed following wet ashing 
with a HNO,-HC1O, mixture; these were reanalyzed 
along with the remaining samples when the contractor 
changed to a dry ashing procedure. 
Numbered cups of all samples, including randomly in- 
terspersed control and replicate samples, were shipped in 
the frozen state by the College Park Laboratory to Omni 
at regular intervals. Omni was not aware of the contents 
of any cup. 
Control samples were prepared from the raw muscle of 
Pacific halibut by grinding and thoroughly mixing the 
tissue from several large fish. They were packaged iden- 
tically to the other samples. A minimum of 10 controls 
was included in each shipment of 300 sample cups. In all, 
approximately 600 controls were sent to the contractor. 
Four different control samples were used during consecu- 
tive periods of the contract. They were also used at the 
College Park Laboratory as control samples for in-house 
analytical experiments and other contractual work. 
Analytical results for controls were the first items checked 
‘Department of Commerce contract No. 2-35403, June 28, 1972. 
Southeast Utilization Research Center, NMFS. 1975. Arsenic and 
selenium in North American lobster (Homarus americanus) including 
relation to previously determined mercury content. NMFS in-house re- 
port, 71 p. 
