ing tlie succeed ing winter near Salerno and Jupi- 

 ter, about 460 and 540 km. from the point of re- 

 lease. The female recovered at Salerno traveled an 

 average of at least 7.9 km. per day. 



Some sponge female blue crabs migrated from 

 New Berlin directly into the Intracoastal Water- 

 way (north) and apparently entered the ocean by 

 way of other rivers. Ten sponge females tagged at 

 New Berlin (from April to September) were re- 

 captured in the waterway and the Ft. George and 

 Nassau Rivers within 3 to 14 days and before 

 hatching in the ocean and return to inland waters 

 were possible. 



The migration of female blue crabs toward 

 spawning grounds in high-salinity watere re- 

 sembles that in other areas. The similar migration 

 of at least some males, often parallel to females in 

 time and distance, is unlike that reported else- 

 where. In Chesapeake Bay, Van Engel (1958) re- 

 ported that when females migrated downstream to 

 the lower bay, adult males remained in brackish 

 waters and many moved farther upstream. 



Of the 381 tags recovered from female blue crabs 

 tagged in the ocean off the mouth of the St. Johns 

 River, 107 were from inland waters (fig. 4). Of 

 these, 59 were recovered in the St. Johns River, 38 

 in the Nassau River, and the remainder in Cumber- 

 land Sound, Intracoastal Waterway, Crooked 

 River, St. Marys River, and Ft. George River. Six- 

 teen of the crabs that had been tagged off the 

 mouth between May and January were recaptured 

 in the St. Johns River during January, February, 

 and March. These returns indicated, as did the com- 

 position of the commercial catches, that some crabs 

 which spawned the previous season and others 

 which matui'ed and left the river in winter reen- 

 tered the river before and during the earliest part 

 of the spawning season. After their eggs hatched, 

 females continued to enter the St. Johns and Nas- 

 sau Rivei-s during summer and fall. Nearly all of 

 the returns in the St. Johns River were lictween 

 New Berlin and Jacksonville ; a tag from Picolata 

 was the only return upstream from Jacksonville. 

 Returns from the Nassau River were mostly more 

 than 11 km. from the mouth and extended up- 

 stream as far as 32 km. 



Some female blue crabs reenter rivers very soon 

 after their eggs hatch. From May through Sep- 

 tember, the majority of the returns in the St. Johns 

 and Nassau Rivers of females tagged in the ocean 



^ 



JACKSONVILLE 



I I 



30 KILOMETERS 



CROOKED RIVER I 

 CUMBERLAND ISLAND 1 

 CUMBERLAND SOUND 1 

 ST MARYS RIVER I 

 FERNANOINA BEACH 6 

 AMELIA RIVER 1 

 NASSAU RIVER 38 

 INTRACOASTAL V^AIERWAY 1 

 FT GEORGE RIVER 2 

 OFF MOUTH OF ST JOHNS RIVER 251 

 SI JOHNS RIVER 59 

 JACKSONVILLE BEACH 



TOIOMATO RIVER I 

 ■NORTH Of ST AUGUSTINE 6 



SI AUGUSTINE BEACH 2 



CRESCENT BEACH 1 

 MANIANZAS RIVER 2 

 MARINEIAND 4 



LAKE GEORGE 



DAYTONA BEACH : 



TAGGING SITE = 



CAPE KENNEDY 



Figure 4. — Recovery locations of female blue crabs tagged 

 in the ocean ofC the mouth of the St. Johns River. 



(almost all in sponge or recently in sponge) came 

 within 30 days, and most came within 15 days. 

 Fifty-four of the sponge females tagged at New 

 Berlin were recovered in the St. Johns and Nassau 

 Rivers after more than 15 days, and, therefore, 

 after hatching of the eggs. Of these, 40 were re- 

 covered in the rivers as soon as 16 to 45 days after 

 release. 



Eight of nine returns of male blue crabs tagged 

 in the ocean oft" the mouth of the river were re- 

 captured in that vicinity vs'ithin 2 months. One 

 male tagged in August was recovered in the Ft. 

 George River in November. 



LONGEVITY 



In the St. Johns River, relatively few blue crabs 

 survive more than 1 year after reaching maturity. 

 We recovered only 13 tagged crabs more than 12 



BIOLOGY OP BLUE CRAB IN ST. JOHNS RIVER. FLORIDA 



23 



