PROGRESS IN BIOLOGICAL INQUIRIES, 1939 93 
and other predators, by protecting them during the time of egg 
incubation and the hibernating period during the first winter, when 
they are in hiding along the shore just above high-water level. 
Experiments in marine fish farming—Over 15,000 salt-water fish, 
consisting chiefly of striped mullet, did not migrate as usual this 
winter, but instead were forcibly detained in experimental tidal 
ponds constructed at the biological laboratory at Beaufort, N. C. 
Two years ago these ponds were constructed in cooperation with the 
W. P. A. and the North Carolina Conservation Department in order 
to determine the possibility of utilizing salt-marsh ponds and small 
coastal bays for rearing and live storage of fish, and for oyster cul- 
ture. The experimental operations, conducted here since 1938 under 
the supervision of Dr. Prytherch, have demonstrated that by im- 
provement of tidal areas through the construction of dikes, sluice 
gates, or other devices, it is possible to grow mullet, spotted trout, 
flounders, channel bass, sheepshead, croakers, and several other com- 
mon species in captivity, or store them in a live, healthy condition 
for many months until there is a favorable market. The ponds also 
proved satisfactory for protected natural spawning and rearing of 
the mullet, which is the most important food fish taken in the South 
Atlantic and Gulf States. The production of the striped mullet in 
this region amounts to approximately 40 million pounds annually, 
with a return to the fishermen of nearly 114 million dollars. During 
periods when the markets are glutted with mullet the coastal ponds 
would make possible the temporary live storage of a considerable 
quantity, thus maintaining better prices for the fishermen and 
making available a supply of fresh fish at any season of the year. 
In the fall of 1938 the experimental ponds were stocked with over 
3,000 fish ranging in size from roe mullet, weighing over 5 pounds, 
to small immature fish having a length of 6 to 8 inches, which were 
approximately 1 year old. The fish were captured with nets during 
their fall migration and were transported to the pond by means of a 
perforated boat, or live car having a capacity of approximately 400 
pounds. Most of the mullet were placed in the larger tidal pond, 
which has an area of approximately 214 acres at low water, and a 
maximum depth of 15 feet, and receives an exchange of over 5 
million gallons of water daily through the two tidal gates. Several 
hundred immature mullet were placed in the smaller observation 
pond, and in large concrete pools at the laboratory, where they have 
been studied with respect to feeding habits and ability to survive 
low water temperatures during the past 2 winters. The adult mullet 
spawned in captivity during November 1938, and stocked the pond 
with thousands of young which, by the latter part of December, had. 
attained a length ranging from 14 to 34 inch. Though no attempt 
was made to hold these young fish in the pond by the use of fine- 
meshed screen on the tidal gates, there was, nevertheless, a consid- 
erable number that remained in the ponds and grew to an average 
length of over 6 inches during the first year. Less than 1 percent 
of the fish died from injuries sustained during collection and 
transportation, or during the subsequent period of 15 months that 
they were held in captivity. 
Operations during 1939 were conducted on a small commercial 
scale, using a special barge equipped with a built-in live box and 
241635—40—7 
