i110 BULLETIN OF THE BUREAU OF FISHERIES. 
and they are rather more numerous than elsewhere in the waters of Somerset and Dor- 
chester Counties, Md. Pairs of mating crabs are found in great abundance in these 
regions from the middle of July to the last of August. Mating is described on page 115. 
During the spring and summer of 1917, 3,898 crabs were examined either by means 
of the cast shells, the peelers in the floats, or the soft crabs in the packing rooms. It 
was found that in the early part of the season males predominated in numbers among 
the crabs handled for the soft-crab market, i. e., crabs which are immature or just about 
to reach maturity. As the season progressed, the relative number of females increased 
until in August there were more females than males among the crabs caught for the 
soft-crab trade. The following data for*Crisfield, Md., constitute a typical illustration 
of the results obtained at various points on the Bay: 
Date. Males. |Females.| Total. 
Per cent. | Per cent. | Per cent. 
May Bama. kPa «ce seen Se ete nates ore aie ne Un eleeiels oWideise guide slesuevs susiais ne euetes seb cinislusie o\einle 78 22 00 
REIN OTN I5 oe 5 vole oie ca sino oie ew winie win oie wens wien cine aweiengiaaieis en sinonanis e\nhinsiaiQas asia «mide daa dp apie dehy s 58 42 100 
A OTAGE bo Re Rene BAe BCE RBEE De CRGRCAgntc) Saar BRONCO Cae ONE eee snr ee SOREEe incl eS ere ae 42 58 100 
CN AAS CUSE eaey oe atop iw = stew ella) ste ieroie' ete /etetainte w/cia's'stnlajaiaafata:a/etalarh in iwtatn’alnye o's/aleyaie\alu!aicl@lelw e)<lcyeiwinlvlefogeieicVaraigi-ts crew eins 38 62 100 
The data here cited might at first thought lead to the belief that the males pre- 
ceded the females in the migration and were found in greater numbers upon the bottoms. 
It seems to the author, however, that the explanation is simply that the males outstrip 
the females in growth and are the first to reach a marketable size. As the adult size 
of the male is greater than that of the female, in order to complete development in the 
course of a year, a more rapid growth must be maintained by the male than is required 
for the female. ‘This would result in there being during the spring months more male 
crabs of marketable size than females upon the bottoms. As the females developed, 
the relative numbers of the sexes would tend to become more nearly equal. The pre- 
ponderance of females caught during August is doubtless due in a small part to the 
partial depletion of the supply of males during the spring crabbing season. It arises 
mostly, however, from the fact that during August a great number of female peelers, 
while being carried by the males preparatory to mating, are caught on the trot-lines. 
These females, together with those taken by the scrape and the dip net, would make 
the total number of immature females caught greater than that of the immature males, 
which are taken only by the scrape and dip net. As peeler crabs do not eat much, they 
do not bite readily on the trot-line. 
After maturing and mating in the waters of the central and upper parts of the 
Bay, the female crabs migrate southward during the autumn and lie on the bottoms 
of the southern part of the Bay during the winter. While the males move southward 
to some extent, they do not go as far as the females. Not a great many remain as far 
north as Maryland waters, although a few are taken in that region while dregding for 
oysters during the winter. This southerly migration is proved by the following facts: 
First. Very few sponge-bearing crabs are found in Maryland waters; therefore, the 
females that have mated there must have gone elsewhere before the eggs were thrown 
out upon the abdomen. 
