PROGRESS IN BIOLOGICAL INQUIRIES 25 



Dredging surveys made by Mr. Gutsell and a representative of the 

 Fisheries Commission Board revealed scallops in appreciable num- 

 bers in one small area only, a truly alarming outlook. However, by 

 wading over suitable flats near the Beaufort laboratory scallops were 

 found in considerable numbers in a few places. These areas had 

 been devastated by floods the preceding season and made apparently 

 barren, so that no satisfactory explanation for their fertility in 1925 

 can be given. 



Small or seed scallops were very scarce early in the summer, but 

 were obtained in moderate numbers late in the summer and became 

 somewhat more abundant, though probably not normally so, as time 

 passed. 



Measurements of adult scallops show a fairly even and rapid 

 growth from mid July to mid September, a lack of further growth 

 until mid November, and thereafter moderately rapid growth, with 

 no indication of cessation at the end of the year. This renewed 

 growth is also clearly revealed by examination of the shells. The 

 late fall growth was altogether unexpected. The only phenomena 

 with which it seems reasonable to connect the nongrowing period 

 are sexual functionings of some sort. Possibly metabolic activity is 

 diverted from shell growth to the production of spawn. 



The bay scallop is one of the shortest lived of commercial bivalves. 

 In the north, it has been shown that in the majority of cases individ- 

 uals die during or after their second winter and before spawning time 

 the following summer — that is, before the scallops are 2 years old. 

 Although the prolonged spawning complicates matters and data are 

 insufficient for any positive statement as to length of life, there seems 

 to be little doubt that there is a distinct resemblance between the 

 later life histories of scallops in northern and southern waters. 



The scallop is a hermaphroditic species. It is presumed to com- 

 mence spawning some time in the spring in North Carolina. Obser- 

 vations made in July showed that some scallops had spawned, and 

 spawning was observed in August and continued to the end of 

 December. In mid December about half of the scallops contained 

 considerable quantities of spawn and about a quarter of them had 

 large quantities. Evidently observation over a period of at least a 

 year is necessary for even approximate knowledge as to when spawn- 

 ing begins and ends. 



Recommendations for the protection of the scallop beds have been 

 made to the State Fisheries Commission Board based on the results 

 of this investigation. Some of these have already been favorably 

 acted upon, and it is anticipated that further action will be taken in 

 the near future. 



FRESH-WATER MUSSELS 



In addition to the regular annual survey of certain mussel beds of 

 the Mississippi River by the shell expert of the Fairport (Iowa) labora- 

 tory, J. B. Southall, a special survey of the upper Mississippi between 

 Lake Pepin and La Crosse was conducted by Dr. N. M. Grier, of 

 Dartmouth College. A similar survey over the same territory was 

 made by Doctor Grier in 1920. 



