58 BUIvIvETlN OI? THE BUREAU OF FISHERIES. 



by hand to a fore-and-aft position (Pi. XXX, upper figure) ; it is then lowered into 

 the water by unwinding the windlass. The line from the windlass passes through a 

 block overhead (not shown in the picture) and down to the bridle of the dredge. The 

 two pulleys through which the bridle passes should be noted on the ends of the dredge 

 handles. When the brake on the windlass is thrown off, the dredge falls to the 

 bottom, and the dog releases automatically. The dredge now rests on the bottom, 

 covering a space 3 by 6 feet, with the tines of the two ends sticking into the substratum. 



The first effect of turning the windlass, after taking up the slack, is to lift the ends of 

 the handles and bring them together, thus causing the dredge to close. As the dredge 

 closes, the tines thoroughly rake the bottom, and when completely closed every mussel 

 and rock in the space covered, except those so small as to pass through the openings, are 

 taken in the basket. Continued winding of the windlass brings the dredge out of the 

 water, when it can be lowered into one of the boats and opened. All debris must be 

 sorted out and thrown away. A small hand rake, like a flower rake, is used to clear the 

 small stones which may have been wedged between the tines. In view of the contin- 

 gency that the dredge may be fouled by a log or heavy stone, it is necessary to have a 

 clearing line attached to one end of the dredge. A small windlass must be used to operate 

 this line if the dredge is very heavy. The effect of hauling on this line is to open the 

 dredge, which may have been partly closed, and bringit up to the surface; the haul is of 

 course lost in such a case. Heavy dredges are more effective than the light ones. 



The cost of the larger dredge was $65 complete, with boats and all ; but there was 

 very small expense for labor, as the work was done during the slack season and largely 

 by the owner. The ordinary complete cost of such an outfit would be $100 or more. 



If the openings between the tines are wide enough, the small shells will not be re- 

 moved from the bottom. Comparing the dredge with the crowfoot drag, it may be 

 noted that the latter takes mussels by chance and that repeated dragging over the same 

 bottom is necessary to make an approximately clean catch, while the former makes a 

 dean haul of only the mussels large enough to be taken. It will be seen, therefore, that 

 the crowfoot apparatus, although less effective over a given small portion of bottom, is 

 actually more destructive to the young mussels. 



An entirely new form of dredge has recently been invented, which is operated by 

 power and brings the mussels continuously from the bottom by means of an endless 

 chain and buckets. No detailed description can be given at this time. 



LOCAI^ MODIFICATIONS OF METHODS. 



Various other forms of apparatus have been devised at different times and put into 



temporary use, but none of them seems to have won a place in the established methods of 



fishery. There are many local variations of the typical methods described, but it is 



not practicable to describe them all. Two special modifications of the use of the coke 



fork and of the basket rake were thus described as used in the James River in 1913:** 



The mussels [at Riverside, S. Dak.] were gathered with a coke or coal fork, having a piece of 2 by 4 

 lumber fastened to the handle, the length of this piece being according to the depth of the river. This 

 fisherman had a novel way of anchoring his boat. At each end of the boat a hole was bored through the 

 bottom large enough to insert a piece of 1.5-inch pipe, making a water-tight joint. These perpendicular 



a Coker, R. E., and Southall, J. B.: Mussel resources in tributaries of the upper Missouri River. Appendix IV, Report, 

 U. S. Commissioner of Fisheries for 1914, 17 p., i pi., i map. Washington, 1915. 



