466 



SCIENCE, 



[Vol. VI., No. 147. 



moUusks may not be smothered and killed during 

 the most critical period of their lives. 



4. Artificial fertihzation of the eggs of the 

 oyster is feasible, and wiU become an important 

 adjunct to successful spat-culture. 



5. The water charged with embryo oysters may 

 be passed through a steam-pump without injury. 



6. Oyster fry usually adheres most freely to the 

 under surfaces of shells or other collectors, be- 

 cause the lower side is cleanest, and most favorable 

 to the survival of the animals. 



7. The spat of the oyster will grow and thrive 

 with comparatively little light. 



8. The specific gravity of the water may range 

 from 1.003 to 1.0235. 



9. The most favorable temperatures of the water 

 for spatting seem to be from 68° to about 78° to 

 80° F. 



10. Spatting will occur just as freely in ponds 

 or tanks with a free circulation as in ojjen water. 



These are the 'elementary principles upon which 

 we must base our new method. All have been 

 verified by observation, and none of them are 

 hypothetical ; but to give an account of all the 

 data upon which they are based would take up 

 too much space here. The methods of sj^at-col- 

 lecting used in Europe are too cumbersome and 

 expensive ; besides, they are inefficient when ap- 

 plied to the American oyster, largely because of 

 its low price. The thing to do is to arrange the 

 collectors in such a way as to expose an enormous 

 area of surface to which the bilhons of fry, swim- 

 ming about in the water, may become adherent. 

 To effect this it is proposed to provide a pond, 

 natural or artificial, and connect it by way of a 

 long, zigzag canal with the open water. The area 

 of the pond, for a good reason, should be about 

 the same as that of the canal. The canal and 

 pond should be of about the same depth, or con- 

 tain about tlu'ee and a half feet of water at low 

 tide. No filters are needed, except, perhaps, a 

 screen at the mouth of the canal to keep out star- 

 fishes, large Crustacea, and predaceous gastropod 

 mollusks. 



The canal is provided with ledges near the top, 

 at about the level of lo\^^- water mark, to support 

 the receptacles for the cultch. These are formed 

 of vertical wooden sti'ips six niches wide, six feet 

 long, and secured parallel to each other, and three 

 feet apart, by a cross-piece at the top, and two 

 horizontal side-pieces six inches wide, secured 

 two feet six inches from the top of the vertical 

 pieces. Coarse galvanized wire netting is then 

 secured around the edges and low^er ends of the 

 vertical strips below the two parallel cross-pieces. 

 This netting will then form, with the wooden 

 frame, a basket three feet wide, three feet deep, 



and six inches thick. Such a basket will hold 

 somewhat over three bushels of oyster-shells as 

 cultch. The two cross-pieces which project be- 

 yond the vertical pieces will support the receptacle, 

 with the shells which it contains. One of these 

 receptacles is allowed to every running foot of 

 canal, in which its position is vertical. The re- 

 ceptacles are therefore placed six inches apart. A 

 pond forty feet square, and accommodating 100 

 bushels of spawning oysters, on two superimposed 

 platforms, wiU supply enough fry for a canal 400 

 feet long, and holding 1,200 bushels of shells as 

 cultch in 400 receptacles. The latter will cost, at 

 the lowest rate for material and labor, $50 per 

 hundred, or $200 for 400 feet of canal. One 

 bushel of oysters will yield about one billion of 

 eggs and fry. The pond, with its hundred bushels 

 of spawning adults, will therefore yield about 100 

 billions of fry. This vast multitude of oyster- 

 brood will be wafted back and forth through the 

 collectors by the tides 360 times during the spatting 

 season, which lasts for ninety days. That is, 100 

 billions of fry will be wafted through 1,200 bushels 

 of shells 360 times during the season, thus insuring 

 the fixation of the largest possible percentage of 

 embryos. The shells can be kept clean by vibrat- 

 iug the receptacles on the ledges which support 

 them. It will thus be seen that on one-tenth of 

 an acre I can place as much cultch as could ordi- 

 narily be placed on four acres. Or, by my method, 

 on one acre I can put down as many shells as 

 could be put on forty acres by those who simply 

 sow the shells ; that is to say, the business of 

 getting ' sets ' for planting in the open w^ater may 

 be so condensed as to cover only one-fortieth of 

 the ground now covered. After the lapse of ninety 

 days, the cultch, with its adherent spat, is removed 

 from the collectors, and sown in the open water. 

 The method is therefore solely for the purpose of 

 propagating the oyster, and commends itself as the 

 most feasible in the Chesapeake region, where it 

 is hoped that private enterprise wiU estabhsh 

 nurseries where seed-oysters alone will be culti- 

 vated, to supply the demand for planting new 

 beds. Thousands of acres of the flat, marshy 

 land skirting the Chesapeake and Chincoteage 

 bays are available, and may now be converted 

 into establishments for the culture of oyster-spat. 

 The plans set forth above are justified in detail by 

 the facts observed by myself in the course of the 

 experiments instituted by me during the last five 

 years, under the auspices of the U. S. fish com- 

 mission. In nature the theory is also abundantly 

 verified, as, for example, at Wood's Holl, Cohasset, 

 and Fortress Monroe. The fullest justification of 

 the conclusions above presented is also given by 

 the results obtained at Cherrystone in 1881, and at 



