schools of fish successfully by transmitting whale 
predator noises; the fish, seeking shelter, concen- 
trated against the bottom. A trawl net, towed 
along the bottom, thereby yielded a greater catch. 
Bubble fences to repel predators or guide fish to 
entrapment devices may depend on acoustic ef- 
fects. Considerable research into the principles of 
operation has been conducted without much 
success to date. Nevertheless, the industry has not 
exploited the results of acoustic gear research to 
the fullest. Undoubtedly, one reason is the inade- 
quate means of communication among the re- 
searcher, the typical user of acoustic gear in other 
fields, and the fisherman. 
(3.) Optics Lights to attract and direct certain 
species are well known and widely used in various 
forms to improve catch. These methods are empir- 
ical and not based on behavioral research which 
could permit optimizing such variables as inten- 
sity, spectral content, geometry, and direction. 
Current experience indicates that such research 
will be fruitful. 
(4.) Electricity Electrical devices to fence, at- 
tract, and immobilize species have received much 
interest, and their potential appears promising. 
Immobilization is relatively predictable, and crude 
design criteria are available. An electro-trawl for 
shrimp developed under the Bureau of Commercial 
Fisheries is now on the market. An electric 
stimulus causes shrimp buried in bottom sediments 
to jump into the path of the trawl. Despite the 
interest in such devices, some feel its use in salt 
water will be confined in the near future to just a 
few fisheries because of economics. 
Future harvesting techniques will make increas- 
ing use of underwater technology, including: (1) 
system designs to view catching devices in opera- 
tion, (2) more effective catching devices resulting 
from redesign based on direct observations, and 
(3) submersibles for various supporting functions. 
In the future, it should be possible to harvest 
whole communities of organisms, particularly 
those in the deep scattering layers. Typically these 
layers contain concentrations of 10 to 12 inter- 
mingled species from a half inch to two inches 
long that rise to the ocean surface at dusk. 
Technological developments should help in har- 
vesting the larger organisms for volume production 
of protein concentrates. 
Many excellent fishing grounds from the stand- 
point of size, reasonable depth, availability of fish, 
and nearness to port are not being utilized because 
of rough bottoms. One such area off the coast of 
Washington contains over 1 000 square miles made 
unfishable mainly by scattered small boulders. 
Explorations have located only a few small tracts 
through which fishermen can tow nets safely. The 
area could be a major fishing ground through use 
of pots, traps, and rugged trawling equipment. 
A primary objective of technological improve- 
ments must be to reduce present fishery produc- 
tion costs. It should be economically feasible to: 
(1) fish in areas of low species concentration, (2) 
fish in depths not worked now by surface fishing 
operations, (3) harvest species lower on the food 
chain, and (4) fish ocean floor areas too rough for 
present gear. 
3. Long-Range Future 
a. Fishing-Up One long-range concept to help 
develop U.S. leadership in the world fishing com- 
munity might be to fish-up (to fish waters above 
from a position on the ocean floor) on the U.S. 
Continental Shelf. Probably many of the tech- 
niques discussed earlier would be utilized in a 
fishing-up system. If successful, the Nation’s fish- 
ing capability would be increased and the competi- 
tive position with foreign nations on our own shelf 
improved. Foreign countries, obviously, could 
develop a similar competitive advantage on their 
shelves. 
b. Modification of the Environment Modifying 
the environment to improve productivity of se- 
lected species is not practiced on a commercial 
scale. However, the possibilities of increasing 
nutrient concentration through fertilizing or 
artificially-inducing upwelling, of providing arti- 
ficial cover (artificial reefs or floating plastic kelp 
beds), and of improving or creating spawning 
conditions (probably in shallow bays, lagoons, and 
estuaries) should be considered. 
Increased knowledge of the ecology and physi- 
ology of desirable species must be obtained if such 
modifications are to be economically feasible. 
Further, economic feasibility probably will require 
establishing systems to utilize organic wastes for 
nutrition and waste heat to induce upwelling or 
temperature control in confined waters. A much 
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