APPENDIX III APPENDIX III 
These imports increased 66 percent from 1970 to 1974 
but decreased significantly in 1975 as canners cut back on 
their use of imported tuna in order to reduce inventories. 
A U.N. report states that a close relationship exists 
between trends in tuna prices in the United States, Japan, 
and Europe. Value differences among species are related 
to market preference, fish size, the resulting yield during 
processing, labor costs, and quality. Albacore has the 
highest market preference in the United States because of 
its white color and bland flavor. Because skipjack has the 
lowest yield (number of cases per ton of raw fish) and is 
the least popular it has the lowest value. 
The U.N. report also noted that U.S. prices were weak 
during the early 1960s, having been considerably higher in 
1954 and 1955. Since 1964 prices have begun to rise, as 
world supplies have begun leveling off. The trend in 
prices for raw materials was clearly upward in the mid-1960s 
and sharply higher in the 1970s. According to NMFS, the pres- 
sure of tuna's expanding demand relative to a fixed supply 
will put increasing pressure on tuna prices. 
Pushing pt leet 
The U.S. tuna fleet is based primarily in southern 
California and operates from San Diego and San Pedro. We 
were told the fleet is composed of three types of fishing 
vessels; purse seiners, baitboats, and trollers. Purse 
seiners generally locate tuna schools by visually locating 
porpoises. The majority of the yellowfin tuna catch is 
caught in association with porpoise, as the two species swim 
together. Porpoise swim on the ocean's surface while yellow- 
fin tuna swim at lower depths. When porpoise are observed, 
the purse seiner's captain encircles both the porpoise and 
tuna with a large net with a circumference of up to three- 
quarters of a mile. The bottom of the net is then closed, 
or "pursed," forming a large bag or purse, trapping the 
enclosed tuna. The net is then pulled aboard the vessel 
and the tuna are placed in refrigerated holds. This method 
of catching tuna is referred to as fishing "on porpoise" 
because it results in the incidental catch of porpoises. 
The U.S. purse seine fleet consisted of 139 vessels 
with an aggregate carrying capacity of 115,400 tons in 1975. 
An NMFS official told us that larger purse seiners ranged 
from 200 to 275 feet in length with carrying capacities up 
to 2,675 tons, and when fully equipped cost from $3.5 to 
$5 million each. The usual crew size is 10 or more men. 
We were told the U.S. purse seine fleet is capable of fish- 
ing in any of the world's oceans, with the majority of the 
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