any of the other species. They were uncommon in 

 the catches shallower than 40 fathoms in the stand- 

 ard series. Data from additional trawling of the 

 R/V's Cisco and Kaho indicate that foiirhom scul- 

 pins are j) resent in the deepest part of the southern 

 basin (90 fathoms) and are abundant to at least 

 70 fathoms. They are found at least as deep as 140 

 fathoms in northern Lake Michigan, where their 

 range does not appear to extend into as shallow 

 water as in the southern basin. Deason (1939) esti- 

 mated the depth of greatest abundance of f ourhorn 

 sculpins in Lake Michigan as 40 to 75 fathoms on 

 the basis of tlieir occurrence in stomachs of lake 

 trout and burbot. Fourhorn scidpins in the Apostle 

 Islands region of Lake Superior were seldom shal- 

 lower than 50 fathoms (Dryer, 1966) ; they were 

 fairly abundant in R/V Ci^co trawl catches at 200 

 fathoms in eastern Lake Superior in 105-3. 



Larval fourhorn sculpins are in tlie hyijolimnion 

 in deep areas. No other information is available on 

 distribution in the first year. 



Although the standard series did not cover a 

 large enough portion of the depth range of four- 

 horn sculpins to give a good indication of seasonal 

 distribution, certain features are evident from tiie 

 data. The species was always aljiuidant at 45 and 

 50 fathoms, but was never numerous at other 

 depths (table 10). It extended its range slightly 

 shoreward in spring. None were shallower than 

 45 fathoms on February 13, but a few were as 

 shallow as 35 fathoms on March 11 and 17 fathoms 

 on April 15. Numbere which had been considerably 

 larger at 50 fathoms than at 45 fathoms in Feb- 

 ruary-May were usually larger at 45 fatlioms 

 afterwards. Distribution showed no obvious change 

 in summer and fall. 



The shallowest water in which a fourhorn scul- 

 pin was caught in tlie standard series was 7 fath- 

 oms (May 26) , but one specimen, seemingly in good 

 condition, was taken at 4 fathoms off Saugatuck 

 in August 1965. 



The segment of the depth range of fourhorn 

 sculpins sampled in the standard series was too 

 small for an evaluation of the size-depth relation. 

 The average individual weight in most catches was 

 0.8 to 1.0 ounce (22.7-28.3 g.). Fourhorn sculpins 

 in the standard series were not measured, but 80 

 percent of those from identical trawling off Sauga- 

 tuck in 1965 were 4.5 to 5.5 inches (11.4—14.0 cm.) 

 long, and few fell outside the length range 4.0 to 6.0 

 inches (10.2-15.2 cm.). 



OTHER SPECIES 



Several species were caught in such small num- 

 l)ers in the standard series that their depth dis- 

 tribution could not be determined accurately. The 

 limited data available are discussed briefly. 



Sliortnose ciscoes (18 collected) were taken at 5 

 to 50 fathoms, mostly 40 to 50 fathoms. One long- 

 jaw cisco was caught at 15 and another at 50 fath- 

 oms, and individual kiyis were taken at 45 and 50 

 fathoms. Lake herring (62 collected) were taken 

 at 5 to 50 fathoms ; they were most common at 15 

 to 25 fathoms, especially on February 13 and 

 March 11. In the mid-1950's, when this species was 

 more abundant in Lake Michigan, it was fre- 

 quently caught in nets of the R/V Cisco at mid- 

 levels, occasionally near the surface. Studies by 

 Smith (1956) and Dryer (1966) indicated that 

 lake herring in the (xreat Lakes are essentially 

 pelagic during the warm months, but may be 



Fathoms i 



17 



20 



25 



30 



35 



40... _._ 



45 



50 



NuvibeT Number Number Number Number Number Number Number Number Number Number 



' No fourhorn sculpins caught at depths shallower than 17 fathoms, except for one at 7 fathoms on May 26. 



12 



U.S. FISH AND WILDLIFE SERVICE 



