426 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



ordinary troughs, with a gravel covering on the bottom, and a stream 

 running with a slight current over the gravel. Owing to the very 

 light specific gravity of shad-eggs, it was soon found that there was no 

 success whatever to be hoped for by these devices. 



Several experiments of different devices were attempted before the 

 mode now adopted was tried and proved successful. Bat a successful 

 method was discovered and employed sufficiently long before the end of 

 the season to hatch out a large quantity of shad, and the results were 

 apparent to the fishermen of the river three years afterward. 



The apparatus* devised by Mr. Green was merely a light pine box, 22 

 inches long, 15 inches wide, and 12 inches deep; the bottom was of wire- 

 cloth — about twenty wires to the inch. It was used withoirt a cover. 

 On the ends of the box two pieces of two by four scantling were nailed 

 diagonally to the lines of the box, so that floating in the water it was 

 slightly tilted, the side of the box sunk to the least depth being up 

 stream, so that the wire-screen bottom was presented to the current at 

 a slight angle, sufiBcient to produce a circulation of the water inside of 

 the box that kept the light shad-eggs in gentle motion. In a sluggish 

 tide-current the floats are usually nailed on so that from the upper edge 

 of the box to the top of the float in front there is a distance of 5 inches, 

 and from the upj)er edge of the box to the top of the float behind there 

 is 2^ inches. The angle of the floats is of course less for a more rapid 

 current, the object being to produce a current that will move the eggs 

 as gently as possible, a more rapid motion being regarded as injurious, 

 especially in the later stages of development, when it materially hastens 

 the rupture of the shell membrane and effects a too premature birth 

 The wire-screen bottom is coated with coal-tar, or what is better, asphal- 

 tum varnish, both for the purpose of preserving the wire-cloth and for 

 a supposed effect in retarding confervoid growth. 



The boxes are connected by bridles and lines in gangs of six, and to 

 the first box an anchor-line with a large stone at the end holds the g^ng 

 in its place in the river. The box next the anchor has the floats extend- 

 ing both ways beyond the box about 8 inches, but on the remaining ones 

 they are sawed off flush with the box. 



The method employed at the station at Washington is as follows ; 

 The fish are taken in a seine one thousand fathoms long. As soon 

 as the bag of the seine comes near the shore the fishermen, gathering* 

 the lead-line and cork-line in their hands, gradually work it up to the 

 top of the water, shaking the fish into the bunt of the bag. A boat 

 is brought alongside and the fish thrown into it with a scoop-net, the 

 shad being at once separated from the other species. The operators, 

 provided with ordinary six-quart milk pans, containing about three- 

 fourths of an inch of water in the bottoms, are in the boat and, taking 

 up the shad one by one, detect at once, by a gentle pressure on the 

 belly of the fish, if the spawn is ripe by its free emission from the 



* See illustration at end of volume. 



