SILVER MULLET 



413 



lines on the outer Continental Shelf; none were 

 taken on the inner Continental Shelf (fig. 1). 

 These facts, together with the location of a spawn- 

 ing school of mullet near the 20-fathom curve off 

 the lower Florida coast, are strong evidence that 

 the spawning of the silver mullet occurs at sea 

 over the outer Continental Shelf from Florida to 

 North Carolina. 



That the spawning season for silver mullet ex- 

 tends from late March or early April until Sep- 

 tember with peak spawning during April, May, 

 and June is evident from several types of data: 

 (1) No larvae were found in plankton tows from 

 February 16 to March 7, 1953 (cruise 1); early 

 stage larvae were taken in plankton tows from 

 April 22 to May 14, 1953 (cruise 2); and one 

 larva was found in plankton tows from July 16 to 

 August 12, 1953 (cruise 3); (2) young silver mullet 

 20 to 25 mm. long were dip netted as early as 

 April 17 off the lower Florida coast, and a very 

 few under 10 mm. in length were dip netted as 

 late as October (table 2) ; (3) the earliest date 

 young silver mullet were taken along Georgia 

 beaches by seine was April 22 (these ranged in 

 length from 17 to 24 mm.); and some specimens 

 from 20 to 30 mm. long were taken in October, 

 although scarce after August (fig. 22 and table 3). 

 Assuming a minimum of 3 weeks and a maximum 

 of 4 weeks for the larvae to reach a size of about 

 20 mm. after hatching, the extreme dates of 

 spawning I have suggested are reasonable. Peak 

 spawning of April to June is evident from num- 

 bers of young dip netted and seined during periods 

 that would yield young from spawning during 

 these 3 months (tables 2 and 3, and fig. 22). 



Spawning of the silver mullet begins with the 

 rise of water temperatures in early spring. In 

 table 4 we see that during late February and early 

 March the surface temperatures over the Con- 

 tinental Shelf in general averaged under 20° C, 

 but exceeded 20° C. during April and May. 

 Perhaps rising temperatures stimulated spawning 

 activity and are more important than absolute 

 temperatures, since spawning continues into 

 summer when water temperatures are much 

 warmer. 



MOVEMENTS AND HABITAT OF LARVAL 

 AND JUVENILE FORMS 



From data contained in tables 1, 2, and 3, in- 

 formation presented in figures 1 and 22, and 



Table 4. — Average surface water temperatures (° C.) and 

 salinities (°/oo) for the several sections of the area from 

 Cape Hatleras, N. C, to the Florida Straits for Gill 

 cruise 1 (Feb. 10 to Mar. 10, 1953), Gill cruise 2 (Apr. 16 

 to May 15, 1963), and Gill cruise 3 (July 15 to Aug. 16, 

 1953) 



[The southern section comprises that part of the area Ivlng between Jupiter 

 Inlet and Jacksonville. Fla.; the central section from Jacksonville, Fla. 

 to the North Carolina-South Carolina boundary; and the northern section 

 from this point north to Cape Hattenis. In general, the inner shelt com- 

 prises waters lying between the beach and about halfway from the shoreline 

 to the lOO-fathom line (mostly waters less than in fathoms deep); the outer 

 shelf, the remaining area out to the inofathom line; and olTshore, that part 

 of the area from the lOO-fathom line to beyond the axis of the Qulf Stream] 



discussions on development and spawning, several 

 facts relating to movements and habitat of larval 

 and juvenile mullet from hatching to a length of 

 about 120 mm. are evident. The larvae spend 

 the first several weeks of their lives in the open 

 ocean as far out as the axis of the Gulf Stream. 

 At a length of about 17 to 25 mm. these larvae 

 move inshore (no silver mullet more than 25 mm. 

 in standard length was taken by dip netting in 

 offshore waters). In Georgia waters (about center 

 of the South Atlantic coast of the United States) 

 these young are taken first on the beaches late in 

 April and then in the marshy estuarine areas in 

 May. Recruitment of young from the ocean con- 

 tinues in volume until August, after which re- 

 cruitment is erratic and small. The young live 

 and grow in the rich estuarine habitat until 

 October or November at which time they have 

 reached lengths up to 120 mm. At this time 

 the young mullet apparently move from the 

 marshy estuarine areas to the outer beaches. 

 By December they appear to depart from the 

 beach area, and perhaps the Georgia coast, as the 

 species was not taken in the seine collections from 

 January until late April when the young (17 to 

 25 mm.) appear. Trends in temperature and 

 salinity of the marsh and beach habitat are shown 

 in table 5. 



Jacot (1920, p. 223), in regard to young M. 

 curema at Beaufort, N. C, states, "At Beaufort 

 they have not been recorded earlier than May 



