382 



BULLETIN OF THE BUREAU OF FISHERIES 



BATHYMETRIC DISTRIBUTION 



The small-meshed nets mentioned in the preceding paragraph were set either 

 with the commercial trout nets or in gangs by themselves at depths of 11 to 100 

 fathoms. These nets always took zenithicus at every set, except the one set made 

 in'Moffat Strait on September 25, 1923, in 13 to 14 fathoms; and records 2, 3, 6, 

 10, 14, 15, 16, 19, 28, 29, 31, and 32 show that some specimens also became entangled 

 in the trout nets themselves. While these data seem to indicate that the species 

 is rather widely distributed, both vertically and horizontally, it is noteworthy that 

 few sets were made more than 15 miles from land (see fig. 3) or, whatever their 

 remoteness from shore, were more than a few miles from 30 or 40 fathoms shoals, 

 from which the descent into depths of 80 fathoms or more is abrupt. It may be 

 stated, then, that zenithicus ranges along the shores of Lake Superior at depths of 

 from 11 to 100 fathoms. Whether it goes deeper is not known. It is unlikely that 

 it often comes shallower, at least not in the fishing season, as it is unknown as an 

 accidental inclusion among the artedi and reighardi that often are taken in the 

 pound nets set at 4 to 10 fathoms out of various ports. 



RELATIVE ABUNDANCE 



The lifts of the special 2% and 2}4 m ch nets set out of the various ports are 

 the only source of data on the relative abundance of zenithicus at any locality or at 

 any depth. While the amount of netting used was relatively insignificant when the 

 expanse of the lake is considered, yet the number of fish taken in a given period 

 indicates in some measure their abundance along the bottom. Out of Sault Ste. 

 Marie, Mich., a gang of 1,800 feet of netting set on June 12, 1922, 10 miles NW. 

 by W. x /i W. of Point Iroquois Light in Whitefish Bay, and lifted on the 14th, had 

 about 200 fish, or 55 fish per night per 1,000 feet (record 1), of which virtually all 

 were zenithicus. Out of Marquette, Mich., 6 miles NE. % N., in 42 to 65 fathoms 

 on August 8, 1921, 2,500 feet of net took about 250 fish after having been set five 

 nights, or 20 fish per night per 1,000 feet (record 4); and the same amount of netting 

 lifted on August 11, 18 miles NE. by N., in 100 to 80 fathoms, after seven nights 

 out, had about 200 fish, or 11 fish per night per 1,000 feet (record 5). All but 10, 

 or 96 per cent, of the fish taken on the 8th and all but 35, or 88 per cent, of those 

 taken on the 11th were zenithicus. Out of Ontonagon, Mich., on August 24, 1921, 

 in 2,500 feet of netting lifted 21 miles west in 15 to 45 fathoms, after having been 

 set for seven nights, about 700 fish were taken, or 40 fish per night per 1,000 feet 

 (record 11); and a similar gang lifted on the 25th, 6 miles NNW. in 20 to 38 fathoms, 

 seven nights out, had about 500 fish, or 28 fish per night per 1,000 feet (record 12). 

 Both these gangs took virtually nothing but zenithicus. Between Cat and South 

 Twin Islands, of the Apostle group, 2,200 feet of net lifted on July 11, 1922, after 

 one night out, from 15 to 20 fathoms, had about 300 zenithicus, or 136 fish per 

 night per 1,000 feet (record 13), and virtually nothing else. 



Three thousand feet of net lifted 20 miles NE. by E. of Duluth on July 17, 

 1922, in 30 to 40 fathoms, after two nights, had about 200 pounds of fish, probably 

 500 individuals (record 17), of which virtually all were zenithicus. Out of Grand 

 Marais, Minn., in 3,500 feet of net set off Terrace Point in 30 to 65 fathoms and 



