Deep sea thermometers and salinometers allow him to take the temperature 

 and salinity of the water at different depths to avoid the laborious setting of 

 a trawl except where the temperature and salinity indicate suitable hydro- 

 graphic conditions for the cod. 



Contrary to the last sailing vessels of the great fishery, which fished ex- 

 clusively in Newfoundland. waters, and later in Greenland, the trawlers fish 

 everywhere cod is found, at Newfoundland, Iceland, Green^lhd, in the neigh- 

 borhood of Bear Island in the Barentz Sea, as far as Nova Zembla. In gen- 

 eral, they do not fish much around Iceland where, in spite of the use of rol- 

 lers, certain rough bottoms constitute a permanent danger to the trawls. 

 Leaving a full month earlier than the sailing vessels, they make, usually, 

 two trips a year. 



In Newfoundland waters, the areas most frequently fished by the sailing 

 vessels by line trawl are often unsuitable for the trawlers. The Platier 

 region, for example, excellent for the first, presents in its eastern part 

 only hard and rough bottom, littered with hollows, bumps, pinnacles, as 

 well as wrecks and lost anchors. A trawl set there is immediately torn to 

 pieces. Until the end of spawning, it is only on the slopes of the Grand 

 Banks, in depths sometimes exceeding two hundred fathoms, that the trawl- 

 ers seek concentrations of cod. 



The continental shelf of the Newfoundland banks rises almost perpendic- 

 ularly from great depths. In certain regions, the difference in level changes 

 500 fathoms in less than 4 kilometers, a slope close to 30 percent. 



On this slope, waters of different temperatures are found distributed in 

 narrow layers. The cod, seeking the most favorable temperature and salin- 

 ity, is found in certain of these strata, where it gathers. At a depth 5 to 10 

 fathoms higher or lower than this optimum depth, none are found, for this 

 may be the domain of another species of fish, the haddock for example. The 

 art of the captain of the trawler is to find the depth where the cod is and, 

 having determined it, to follow the contours of this depth with the trawl. It 

 is here that the continuous depth recorder is infinitely valuable, permitting 

 him to direct his course in advance so that the following trawl passes exactly 

 at the desired depth. One sees, moreover, that correct conduct of the course 

 of the trawl in these conditions requires constant vigilance. 



But the cod does not always stay on the slope of the shelf. After the 

 spawning season, it disperses all over the bank, so that the trawlers must 



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