24 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 5. — Embryos of Rulamia milberti, by size group and month, from females collected off the southeast coast of Florida 



between Fort Pierce and Tortugas, 1946-49 



Table 5 shows the length distribution by 

 months of embryos of E. yniJherti from off south- 

 eastern Florida. It is possible that some of the 

 variation in length of embryos near full term is 

 due to inclusion in the sample of measurements 

 from females of widely differing geographical 

 origin, for example northern Florida and Chesa- 

 peake Bay. 



At Salerno, Fla., 5- to 10-mm. sandbar shark 

 embryos were found commonly in July and Au- 

 gust but no large embryos were seen during 

 these months. In June only a few among the 

 large numbers of adult female E. milherfi landed 

 at the Salerno dock contained embryos and the 

 few that were found were 24 inches long. Since 

 no free-swimming young were taken at Salerno 

 or around southern Florida, estimation of the 

 size at birth in this area depends entirely on 

 determination of the maximum length of em- 

 bryos. Records of young E. mMherti from Cape 

 Canaveral, about 60 miles north of Salerno, north- 

 ward are common. Twenty-four-inch embryos 

 from south Florida were found to be most com- 

 mon in May but substantial numbers were seen in 

 April, and one set of 24-inch embryos was taken 

 from a female collected off Marquesas Island in 

 the Lower Florida Keys in Marcli. Eight adult 

 female sandbar sharks were takv'^n on July 2, near 

 the mouth of the Mississippi River. Of these, 

 five contained 24-inch embryos and one had 25- 

 inch embryos. Two had evidently g\ ,-en birth to 

 young just before they were caught. 



Hildebrand and Schroeder (1928) report six 

 E. milterti in their collection from Chesapeake 

 Bay 17% to 251/2 inches long. Presumably these 

 were not embryos. Records furnished by William 

 H. Massmann (in correspondence) for young 

 Chesapeake Bay milberti include specimens from 

 21% to 28 inches that were taken in 10 collections 

 from June 7 to October 7. Massmann's series is 

 not large enough to establish progressively larger 

 size with later dates. 



; Some young E. inUherti may be born prema- 

 turely at lengths of less than 20 inches either be- 

 cause of crowding, in large litters, or extraordi- 

 nary activity on the part of the mother. Cap- 

 tures of very small young in otter trawls, for 

 example, might result from the entry of the 

 mother into the net followed by a successful 

 struggle to escape. This could bring about pre- 

 mature birth of one or more young which might 

 be left in the net. 



Nichols and Breder (1927) note that females 

 carrying young were taken in Great South Bay, 

 Long Island, from June 22 to Augvist 5. Also 

 they state, when released the young were about 

 22 inches long and weighed 2i/o pounds. One of 

 about 3 feet seen in Sandy Hook Bay as early as 

 June 9 may have been of the preceding year. In 

 September 1924, five young ranged from 24% to 

 26 inches in total length. Bigelow and Schroeder 

 (1948) summarized the indications of size at 

 birth from various Atlantic coast records north 

 of Florida in approximately the same way. It is 



