22 TJ. S. BUREAU OF FISHERIES. 



be<^an early in the month. On the other hand, oyster spat on elevated 

 ciiltch used in certain experiments was found to grow rapidly. This 

 suggested the probable desirability of changing the planting of 

 shells for a set of oysters to the us© of other forms of cultch that 

 will keep the young oysters above the bottom. It is expected that 

 following the advice of the investigators of the bureau, elevated 

 cultch, such as brush and suspended netting, will be tried in a com- 

 mercial way by planters in Great South Bay during the season of 

 1922. 



LONG ISLAND SOUND. 



Investigations in Long Island Sound were delayed by the con- 

 tinued study of the exceptional conditions in Great South Bay. 

 When full attention was directed to the section extending from 

 Bridgeport to New Haven, it was found that oysters had spawned 

 exceptionally early, that by the middle of July oyster larvae had 

 already attained to setting size, and that small oyster larvae were 

 more abundant and more generally distributed than usual in these 

 waters. Very soon, with a change from bright and warm to rainy 

 and chilly weather with easterly winds, the larvae disappeared. 

 Although the weather and water again became warm and the oysters 

 were found gradually to be releasing their " spawn," no spawning 

 " wave " was evidenced, and larvae failed again to appear in ap- 

 preciable numbers. In accordance with the indications of these find- 

 ings, the very limited light " set " was very early indeed for the 

 region. While the search for larvae was in progress a temperature 

 survey was made for the purpose of locating areas for possible early 

 spawning oyster beds. Although, when the work began, the season 

 was too tar advanced to permit a study of the most critical, prespawn- 

 ing period, the observations pointed to a distinct superiority of a num- 

 ber of inshore regions for the successful spawning of oysters be- 

 cause of the higher temperatures prevailing. Corresi^onding with 

 reduced industrial activity, as compared with conditions during the 

 war period, and a presumed diminution in discharge of trade wastes, 

 there was evidence of improvement of the conditions of various in- 

 shore waters. 



In another place (p. 13) reference is made to the necessity for 

 more complete and definite knowledge regarding physical and bio- 

 logical conditions, as well as concerning pollution of waters in 

 regions of oyster culture, and to the arrangements that have been 

 made for securing the required information. 



CHESAPEAKE BAY. 



The Chesapeake Bay investigations, made in December, 1921, 

 and January, 1922, by J. S. Gutsell, scientific assistant, were con- 

 cerned with the mussel plague in the Maryland section of the bay 

 and its tributaries. In a large part of this area hook mussels, 

 Mytilus haTuatus, were so abundant on the oysters as to make the 

 cost of marketing the oysters almost if not quite prohibitive. . It was 

 soon found that in Maryland mussels were most abundant in the 

 upper fresher part of the bay and in the rivers and were absent or 

 insignificant in the lower, saltier waters, including Tangier Sound. 

 It was also found that, presumably because of the clear and dry 



