PROGRESS IN BIOLOGICAL INQUIRIES, 1&22. ^1 



Artificial mussel propagation in large amount was carried on in this 

 region for several years, the shells propagated being the yellow 

 sand-shell and the mucket {Lmnpsills ligamentlna). R. L. Barney, 

 director of the Fisheries Biological Station, Fairport, Iowa, who col- 

 lected the data, has sunmiarized them and has noted a direct correla- 

 tion between the amount of artificial propagation of the yellow sand- 

 shell and the frequency of this shell in commercial shipments six to 

 eight years later, the attainment of salable size for this mussel re- 

 quiring approximately six growth seasons. Mr. Barney's findings 

 are also borne out by the observations of representatives of the but- 

 ton companies buying shells on the ^^Tiiite River. 



THE OYSTER. 



Investigations relating to oysters and oyster culture were con- 

 ducted during the fiscal year by J. S. Outsell, scientific assistant, 

 aided after the first few weeks by Herbert F. Prytherch. Besides 

 continuing the studies, which have been prosecuted for several years 

 in Long Island Sound and Great South Bay on the south side of 

 Long Island, special attention was given during the winter to a 

 relatively disastrous plague of mussels that occurred in Chesapeake 

 Bay. 



GREAT SOUTH BAY. 



Investigations in Great South Bay revealed an early and excep- 

 tional abundance of larvae, most of which appeared in two great 

 " waves." These larvae were to be found all over the principal oyster 

 sections of the bay. The length of the period from attainment by 

 the larvae of earliest readily collectable size to attainment of setting 

 size was found on apparently good evidence to be 10 to 12 days, with 

 13 to 15 days indicated for the total period from fertilization to 

 setting. Corresponding with the distribution and abundance of the 

 larvae, spat was exceptionally abundant over the principal oyster 

 area. It appeared at the time in the abundance indicated by the 

 quantitative catches of larvae. Soon after the setting of the second 

 wave of larvae, an unhealthy condition of the spat became noticeable, 

 and a high mortality prevailed. Great loss occurred from smother- 

 ing by the " sand " formation built up by Sabellaria, a tube-dwelling 

 worm, by the sinking of the cultcli into the soft bottom of certain 

 areas and by the attacks of the drill, JJ rosaljpmx cinereus. Appar- 

 ently, however, the chief cause of mortality lay in some condition of 

 the bottom that brought about a stunted condition and death of such 

 spat as was not elevated above the very bottom by its position on the 

 cultch. Much of the bottom was found to consist of a black muck, 

 evidently of high organic content and smelling strongly of hydrogen 

 sulphide supposed to be poisonous and known to be highly oxygen 

 consuming. Although it seems probable that such a condition of 

 the bottom must be detrimental to the spat, all attempts made in 

 conjunction with the Bureau of Chemistry to find a reduced oxygen 

 content of the bottom layer of water failed. Later laboratory ex- 

 periments were similarly inconclusive, although the mud was found 

 to bring about very rapid oxygen reduction under certain conditions 

 and to yield great quantities of gas. 



Great quantities of spat, which were to have been shifted to other 

 grounds in September, were practically all dead when operations 



