acoustic — relating to, containing, producing, 

 arising from, actuated by or carrying sound. 



aquaculture — cultivation of natural fauna 

 resources of water. 



biomass — the dry weight of living matter, in- 

 cluding stored food, present in a species 

 population and expressed in terms of a 

 given area or volume of the habitat. 



catch effort — the ratio of amount of fish 

 caught to some measure of fishing effort 

 such as the number of days a typical vessel 

 is fishing. 



demersal fish — living at or near the bottom of 

 the sea. 



electro-optics — the study of the influence of 

 an electrical field on optical phenomena, as 

 in the electro- optical Keer effect and the 

 Stark effect. Also known as optoelectronics. 



ex-vessel — price received by fisherman for 

 fish, shellfish, and other aquatic plants and 

 animals landed at the dock. 



finfish — classes cyclostomata, elasmo- 

 branchin and pieces of the phylum ver- 

 tebrata; excludes other marine organisms. 



fish meal — a protein rich, dried-food product 

 produced from inedible portions of fishes 

 by dry or wet rendering. Also known as fish 

 protein concentrate. 



fish oil — oil obtained from fish such as 

 menhaden, herring, sardine, and pilchard; 

 used as a drying oil in paint and as a raw 

 material for detergents, resins, and 

 margarine. 



gear — implements developed for the capture 

 of all aquatic animals. 



gill net — a wall of webbing suspended ver- 

 tically in the water by means of weights 

 (lead) on the bottom line and corks on the 

 top line. The webbing may be made of cot- 

 ton, linen, or synthetic material. The mesh 

 is selected according to the fish which will 

 be captured. 



grouiidfish — broadly, fish that are caught on 

 or near the sea floor. Bottomfishes, 

 rockfishes, and flatfishes, cod, haddock, 

 pollock, and Atlantic ocean perch. 



hydroacoustics — study of the propagation of 

 sound waves in water, especially in the 

 oceans, and of phenomena produced by 

 these sound waves. Also known as under- 

 water acoustics. 



landings — commercial quantities of fish, 

 shellfish and other aquatic plants and 

 animals brought ashore and sold. Landings 

 may be in terms of round (live) weight or 

 dressed weight. Landings of crustaceans are 

 generally on a live-weight basis except for 

 shrimp which may be on a heads-off basis. 



Loran-C — a low frequency radio navigation 

 system by which hyperbolic lines of posi- 

 tion are determined by measuring the 

 difference in the times of reception of syn- 

 chronized pulse signals from two fixed 

 transmitters; as compared to Loran-A, time 

 difference measurements are increased in 

 accuracy through utilizing phase com- 

 parison techniques in addition to relatively 

 coarse matches of pulse envelopes of 

 received signals within the Loran-C 

 receiver. 



magnetic — having properties of a magnet; ex- 

 hibiting magnetism; phenomena involving 

 magnetic fields and their effects upon 

 materials. 



maximum sustainable yield — the balance be- 

 tween the capacity of the resource to renew 

 itself and the harvest that man can take. 



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