62 U. S. BUREAU OF FISHERIES 
revealed no ill effect from the dredging operations. There was no 
accumulation of mud on oyster shells or in the shell cavities. The 
oysters appeared to be healthy and normal. It is planned to continue 
snes surveys in Narragansett Bay as long as the dredging operations 
ast 
Mortality of shellfish, Myrtle Sound, N. C_—At the request of the 
North Carolina Department of Conservation and Development, Dr. 
Prytherch made a survey of an unusual mortality of clams and 
oysters in the waters of Myrtle and Masonboro Sounds. It was 
found that hydrographical and biological conditions in these sounds 
had changed considerably since the construction of the Intra- 
coastal Waterway and had proved to be detrimental to the growth 
and propagation of shellfish in this coastal region.: The most im- 
portant modification is the connection of the Cape Fear River with 
the southwest end of Myrtle Sound by means of a canal, approxi- 
mately 100 yards wide, known as Snows Cut. This canal, being open 
at all times, permits a considerable quantity of fresh water, or water 
of low salinity, to flow into Myrtle and Masonboro Sounds. During 
flood stages of the river especially large quantities of fresh water, 
heavily laden with mud, pass continuously through these sounds 
for extended periods and enter the ocean at Masonboro Inlet. During 
the early part of August the unusual floods occurring in the Cape 
Fear River Basin produced such extreme freshening of the water im 
these sounds as to cause destruction of the natural supply of clams 
and oysters. 
The value of the oyster crop of this region, which prior to 1932 
was approximately $3, 000 annually, decreased to less than $400 in 
1936 and 1937. It is evident that the clam and oyster resources of 
this section, which have a combined value of $15,000 annually and serve 
as a means of food and livelihood for a lar ge number of local people, 
should be restored after some satisfactory flood control devices have 
been installed to control the flow of fresh water from the Cape Fear 
River. 
AQUICULTURAL INVESTIGATIONS 
Dr. H. S. Davis, 7n charge 
It has long been recognized that our inland waters constitute one 
of the great “natural resources of the country which, like other re- 
sources, are now suffering serious depletion. Industrial and agri- 
cultural development have so changed the nature of many waters 
that they are no longer suited to fish, while the majority of those 
that are still capable “of supporting eame and food fishes are badly 
overfished. These conditions can best be corrected by wise manage- 
ment combined with artificial propagation. 
The work of the aquicultural investigations has developed along 
three principal lines. One deals primar ily with field problems and the 
provision of much-needed information on the best means of obtaining 
the maximum production of game and food fishes consistent with 
environmental conditions. A second line of investigation is con- 
cerned with problems relating to the artificial propagation and rear- 
ing of fish, while the third deals with fish parasites and diseases, and 
their control. 
