. Bulletin of the United States Fish Commission. Fisheries -- United States; Fish-culture -- United States. STURGEON HATCHING ON THE DELAWARE RIVER. 337 1. The shallow trays to which the eggs are affixed have, as far as the writer can find, been constructed either of fine metal gauze* or of cheese In the present experiments the use of a coarse-meshed "mosquito netting" was found to give most satisfactory results. Of a tray bottom of this material, the perforations are suffi- ciently large to admit an egg, but not so large as to permit it to pass through; a tray properly prepa
. Bulletin of the United States Fish Commission. Fisheries -- United States; Fish-culture -- United States. STURGEON HATCHING ON THE DELAWARE RIVER. 337 1. The shallow trays to which the eggs are affixed have, as far as the writer can find, been constructed either of fine metal gauze* or of cheese In the present experiments the use of a coarse-meshed "mosquito netting" was found to give most satisfactory results. Of a tray bottom of this material, the perforations are suffi- ciently large to admit an egg, but not so large as to permit it to pass through; a tray properly prepared retains a single layer of eggs, which maybe aerated as conveniently on the under as on the upper side. 2. In former experiments the eggs, becoming viscid, appear to have been lifted from the water, spread upon the trays, and retained thus until their attachment. In trials made at the suggestion of Mr. Pancost, of Delaware City, the eggs were spread upon immersed trays. Under water the eggs are easily handled, flowing smoothly over the netting tray, and by careful tapping of the tray frame may be made to assume a single layer. Placed on the tray ten minutes after fertilization they become firmly attached within twenty Diagram of floating case used in sturgeon hatching. 3. To secure the free circulation of water necessary to the hatching process, the egg trays are arranged in stout wooden cases, which float in the current or are sunk (Gliickstadt, Elbe) in deep water. Bottom and two sides of the cases covered with metal gauze permit a free passage of water current. In the present experiments the floating hatching-case differed from any of which the writer is aware in the following regards: It was nearly as deep as wide. By this means the hatching-trays might be placed almost vertically, to thus take advantage of the water current and at the same time economize space. As many as four trays to a case were successfully employed; these, held in position by cleats, were
Size: 2147px × 1164px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookcollectionbiod, bookdecade1890, bookyear1893
