FISHING GEAR AND FISHING METHODS 271 



5 to 25 feet of water and fishermen operate on an average of 150 pots per man. 

 Sucli pots weigh about 35 poimds each, cost relatively little, and can be expected 

 to last 3 to 5 years. 



Eel pots, typical of the Middle Atlantic States, are made of oak splints woven 

 in basket-weave design. They are also cylindrical, 8 inches in diameter, 24 inches 

 long, but taper to 6 inches at the mouth or funnel end. This funnel is also made 

 of the same material and extends inside the pot two-thirds its length, having an 

 opening only 2 inches in diameter at the inside end. Since the pots are light in 

 weight, one man can operate as many as 300. These are set in strings of 25, which 

 are attached to 10-foot gangions on a long Manila trawl line. When "river 

 pirates" molest the traps, fishermen find it expedient to anchor both ends of the 

 lines rather than to buoy them, after first ascertaining their position by taking 

 a land fix bearing. 



Electronic Marine Devices in Fisheries 



A foreign visitor to United States' fisheries, in almost any section of the country, 

 will undoubtedly be attracted by the numerous types, applications, and wide 

 variety of electronic instruments aboard the larger tonnage vessels for locating 

 subsurface schools of fish. He will also notice fishermen who continue to catch 

 fish with the traditional hook and line, taking one fish at a time. However, since 

 each method produces for a definite market, there is no conflict. The larger vessel 

 catches fish for the modern "production line" fish-processing houses. The line 

 fishermen produce for the local fish market or often sell directly to the consumer. 



Certain scientific precision instruments are today practically standard equip- 

 ment aboard modern fishing vessels. "Ship-to-ship" and "ship-to-shore" radio 

 telephones, radio direction finders, and subsonic depth recorders were the first to 

 attain popularity. Short-wave radio telephones, with which most of us are familiar, 

 were first to appear about 1929. Practically every registered vessel in the fisheries 

 is now equipped with at least one of these items, especially the telephones and 

 direction finders. 



During recent years electronic subsurface detectors were successfully developed, 

 and many of these have been adapted for use in the marine fisheries. A few of the 

 more highly specialized instruments, particularly radar and sonar, are already in 

 use in fishery operations. They not only facilitate safer navigation, but also save 

 time in searching for schools of fish. Considerable promise is held for their future. 



Electronic Depth Recorders. Shortly after the widespread installation of radio 

 telephones on practically all of the offshore fishing vessels, the automatic depth 

 recorder made its appearance about 1930. 



The depth recorder sends out a signal in the form of an electrical impulse 

 from a transmitting oscillator attached to the hull to the bottom or the floor 

 of the ocean. The echo is picked up on the receiving oscillator and is ampli- 

 fied and recorded. In the earlier type a red light flashed beside a number on 

 the dial signifying the depth in fathoms. More recently, as a result of research 

 during the past World War, this instrument has been improved to such a degree 

 that the depth of water is shown as a heavy black line on a paper graph. It is so 

 sensitive that a school of fish beneath the ship can be detected as a second, 

 usually lighter, line above the true bottom. Since this is on a paper graph, it 

 becomes a permanent record, available for use at any time. 



