PROGB.ESS IN BIOLOGICAL INQUIRIES, 1924 31 



" set." The <j:reate,st problem of artificial propagation has been that 

 of retaining the minute larval oysters when supplying them with 

 running water, as they are so small that they will pass through 

 felt or the finest bolting silk until they are several days old. For 

 this purpose a new material known as " filtros " was tested out under 

 various conditions and proved entirely satisfactory. Although these 

 exj^eriments have proved successful on a small scale, there is still 

 much to be accomplished before the method can take its place as a 

 part of commercial oyster culture. 



In order to lay before practical oyster growers and biologists the 

 various problems that have made artificial propagation a difficult 

 task, a report on Experiments in the Artificial Propagation of 

 Oysters has been published (Bureau of Fisheries Document No. 

 961). This work will be continued at Milford during next summer 

 for the purpose of developing the method to a point where it may 

 be of practical value to the oyster industr3^ 



The regular cruises planned for the hydrographic and biological 

 survej^ of Long Island Sound were completed in October, 1923. 

 I'lie survey was inaugurated in 1922 in order to obtain fundamental 

 information relative to the hydrographic and biological conditions 

 having immediate bearing on the problems of oyster culture in 

 Long Island Sound waters. It covered a period of over 15 months, 

 beginning on June 30, 1922, and ending on October 10, 1923. Dur- 

 ing this time the fisheries steamer Fish Hai^k^ emploj^ed for the 

 surve}', made 410 stations, 111 of which were made during the fiscal 

 year just closed. The hydrographic data obtained in field observa- 

 tions were analyzed, and the biological collections are in process of 

 examination. This work has been conducted by Dr. P. S. Galtsoff, 

 naturalist. 



Detailed observations were made on the temperature of the water 

 in the Sound, salinity, dissolved oxygen, acidity (pH), number of 

 bacteria, plankton, spawning of oysters, and sterility of male 

 oysters. 



The results of this surve}' indicate that the difficulties in oyster 

 culture in Long Island Sound ma}- be ascribed to several causes, the 

 following being the most important : 



(1) Most of the spawning beds located in shallow water in har- 

 bors, bays, and in the mouths of rivers are now exposed to pollution 

 either by sewage or by trade wastes; (2) the beds located in clean 

 waters are greatly overfished and have become exhausted; (3) 

 many of the inshore beds, not exposed to pollution, are attacked by 

 starfishes and drills. In East Haven River, for instance, it is esti- 

 mated that more than 50 per cent of the J'oung oysters Avere killed 

 by drills. 



To restore the industry it is believed that it will be necessaiy 

 (1) to protect the beds from pollution, (2) to set aside public 

 spawning beds, (3) to organize methods for the systematic ex- 

 termination of oyster enemies, and (4) to develop the artificial 

 propagation of oysters. 



ALASKA CLAMS 



During the summer of 1923 Dr. F. W. Weymouth, of Stanford 

 University, accompanied by H. B. Holmes, scientific assistant, 

 visited the clam canneries and beds in the vicinity of Cordova and 



