564 U. S. BUREAU OF FISHERIES 



form of construction from States and other agencies who have tested 

 it indicate that it has a high value, and the Hmited experience the 

 bureau has had with it confirms this viewpoint. The new ponds are 

 merely saucer-shaped pools with the outlet at the center and the 

 water supply entering at a tangent, to give a rotary circulation. It 

 is claimed that ponds of this design are capable of carrying increased 

 numbers of trout in a comparatively small water supply and that the 

 fish in them are more evenly distributed than in ponds of the older 

 types. 



TAGGING OF BASS 



While the tagging of trout has been practiced quite extensively by 

 some of the States, by private clubs, and by the bureau, operations of 

 this nature with bass have been rather rare. Recent conditions at 

 the Cape Vincent (N. Y.) station have afforded an unusual oppor- 

 tunity for such work with the smallmouth bass. Brood bass for the 

 ponds at that station are obtained from the St. Lawrence River, under 

 a permit issued by the State of New York. In accordance with the 

 terms of tliis permit the fish are returned to the river after spawning 

 is over, and prior to their release they are tagged with gill cover tags, 

 with the view of checking up on their recapture by anglers. The 

 information gained as a result of two years' tagging operations indi- 

 cates that there is very httle migration on the part of smallmouth 

 bass, the maximum distance covered being from 12 to 15 miles. 



USE OF NICKEL MESH FOR HATCHING MARINE EGGS 



A very satisfactory report has been received from the Woods Hole 

 (Mass.) station on the use of nickel hardware cloth as a covering for 

 the bottoms of trays used in the tidal hatching boxes. This material 

 shows a high resistance to salt-water corrosion, no evidence of deterio- 

 ration being discernible after a full season's use, though the metal 

 tacks used in attacliing it were seriously corroded. The substitution 

 of nickel fastenings should overcome tliis difficulty. 



Several advantages are cited for the use of this nickel mesh in 

 preference to scrim or one of the other cotton fabrics commonly 

 employed in marine hatcheries. It evidently has a life of several 

 years, thus ehminating frequent replacement of the tray covering, 

 whereas the best quality of scrim covering must be renewed every 

 10 or 12 days during a hatching season. Freedom from the necessity 

 of removing and driving tacks in recovering saves the edges of the 

 trays and extends their period of service. Nickel hardware cloth of 

 the same mesh as scrim will remain open to the free circulation of 

 water for many hours after cotton fabric has lost its permeabiUty. 

 It is stated that in collecting cod eggs from the overflow of the spawn- 

 ing cistern the use of scrim has necessitated a change of trays every 2 

 or 3 hours to overcome clogging, whereas trays covered with the nickel 

 mesh function satisfactorily through 8 to 10 hour periods without 

 attention. The higher first cost of the metal is its chief disadvantage, 

 but it is probable that on a long-time basis its use would result in an 

 appreciable saving. 



