EARLY DEVELOPMENT, SPAWNING, GROWTH, AND OCCURRENCE OF 

 THE SILVER MULLET (Mugil curema) ALONG THE SOUTH ATLANTIC 

 COAST OF THE UNITED STATES 



By William W. Anderson, Fishery Research Biologist 



The biology, cliemistry, and physical oceanog- 

 raphy of the waters adjacent to the coast of the 

 United States from Cape Hatteras, N. C, to 

 lower Florida arc little known. Collections by 

 the Fish and Wildlife Service motor vessel 

 Theodore N. Gill provided basic material and data 

 for the study of these conditions as a result of a 

 series of cruises made during 1953 and 1954. 



This paper presents the findings on spawning, 

 early development, growth, habits, and occur- 

 rence of one species. The data contribute to the 

 tremendous task of determining the identity and 

 biology of the numerous fish larvae, a knowledge 

 of which is prerequisite to the understanding of 

 fish populations in the area. 



Opportunity to add to the meager information 

 available on spawning, early life history, growth, 

 habits, and the occurrence in offshore waters of 

 the silver mullet, Mugil curema Cuvier and Valen- 

 ciennes, began off the coast of southern Florida. 

 A school of spawning individuals was located (fig. 

 1) and several running ripe females and ripe males 

 were taken in dip nets. The eggs were fertilized, 

 and during the next several days a developmental 

 series of eggs and larvae was obtained. This 

 series was carried forward with specimens about 

 2.5 mm. to 5 mm. long, from material taken in 

 routine plankton tows; dip-net collections pro- 

 vided a series of specimens ranging in length from 

 about 6 to 25 mm. Finally, our seine collections 

 from the outer beaches and estuarine marsh areas 

 in Georgia extended the series to juveniles up to 

 about 120 mm. in length. 



The silver mullet is known on the Atlantic coast 

 from Cape Cod to South America, and on the 

 Pacific coast from about Chile to the Gulf of 

 California. Along the Atlantic coast of the United 

 States it is taken in commercially significant quan- 

 tities only in Florida, where it constitutes about 

 one-twentieth of the total mullet landings of 

 about .30 million pounds annually. The principal 



Note.— Approved (or publication Februarys, 19i7. Fishery Bulletin 119. 



fishing gears are gill nets, trammel nets, beach 

 seines, and stop nets (Idyll 1949). 



I greatly appreciate the assistance of George A. 

 Rounsefell and Frederick H. Berry for critical 

 review of the manuscript. My special thanks are 

 extended to Jack W. Gehringer for review, also 

 for numerous other aids during the study. 



METHODS 



Eggs were fertilized in several small culture jars 

 and in a glass aquarium of several gallons' capac- 

 ity. It was not necessary to strip either the 

 females or males as eggs and milt were running 

 during the handling of the fish. Sea water from 

 the spawning location strained through No. 1 

 plankton silk was used as the culture medium. 



For some unknown reason the eggs in the large 

 aquarium failed to develop, but hatching was 

 accomplished in all of the culture jars. In an 

 effort to carry some of the larvae through at least 

 the end of the yolk-sac period, they were handled 

 in several ways: some were retained without 

 changing water in the original jars in which fertili- 

 zation took place; some were placed in new water 

 from wherever the ship was at the time; but the 

 majority were removed to fresh jars containing a 

 new supply of strained water from the spawning 

 location. The latter procedure met with the best 

 success. Most of the larvae were dead after 36 

 hours, but one larva survived for 45 hours. 



After fertilization a series of eggs was preserved 

 every 2 hours for the first 12 hours and then every 

 4 hours until hatching at 40 hours. Larvae were 

 preserved at hatching, and then 4, 10, 16, 23, 32, 

 42, and 45 hours after hatching. All eggs and 

 larvae were preserved in 5 percent buffered 

 formalin. 



Biological, oceanographic, and chemical methods 

 used aboard the Theodore N. GUI, general work 

 plan, cruise plans, and objectives are given by 

 Anderson, Gehringer, and Cohen (1956). 



397 



