LARVAE AND YOUNG OF WESTERN NORTH ATLANTIC 

 BOTHID FLATFISHES ETROPUS MICROSTOMUS AND 

 CITHARICHTHYS ARCTIF RONS IN THE CHESAPEAKE BIGHTn 2 



Sally L. Richardson^ and Edwin B. Joseph-* 



ABSTRACT 



Development of smallmouth flounder, Eiropiis microstomits, and Gulf Stream flounder, 

 Citharichthys arctifrons, is illustrated and described from larval to adult stages. Adults 

 occur along the Atlantic coast, mainly from Cape Cod, Mass., to Cape Hatteras, N.C. 

 Larvae of these two species were the most numerous of all flatfishes collected from 1959 to 

 1963 in the Chesapeake Bight by the Virginia Institute of Marine Science. 



Changes in pigmentation, changes in morphology, sequences of ossification, and develop- 

 mental osteology are described and compared. Occurrence of both species as larvae and 

 adults in the Chesapeake Bight, their spawning times, abundance, and economic importance 

 are noted. Taxonomic problems involving the validity of the generic separation of Eiropus 

 and Citharichthvs are mentioned. 



This paper presents the first descriptions of 

 larvae of smallmouth flounder, Etropus micro- 

 stomus (Gill), and Gulf Stream flounder, 

 Citharichthys arctifrons Goode. The larvae of 

 these two species were the most numerous of 

 all flatfishes collected in the Chesapeake Bight 

 plankton by the Virginia Institute of Marine 

 Science (VIMS) from 1959 to 1963. 



Adult E. microstomus and C. arctifrons 

 are found principally from Cape Cod, Mass., 

 to Cape Hatteras, N.C. The reported northern 

 limit for E. microstomus is New England (Parr, 

 1931; Norman, 1934). The southern limit 

 may extend to the Gulf coast of Florida and 

 Mississippi (Springer and Bullis, 1956; Gutherz, 

 1967). C. arctifrons is found from the south- 

 west part of Georges Bank (Bigelow and 

 Schroeder, 1953) to the Gulf coast of Florida 

 and Yucatan, Mexico (Gutherz, 1967). E. 

 microstomus is most common at depths of 

 4-27 m (2-15 fm) and is generally not in the 



'Contribution No. 510, Virginia Institute of Marine 

 Science, Gloucester Point, VA 23062. 



- Part of a dissertation submitted by the senior author 

 to the Faculty of the College of William and Mary in 

 partial fulfillment of the requirements for the degree of 

 Doctor of Philosophy. 



•' School of Oceanography, Oregon State University, 

 Corvallis, OR 97331. 



•* South Carolina Marine Research Laboratory, 217 Ft. 

 Johnson Road, Charleston, SC 29407. 



tidal zone or greater than 46 m (25 fm) (Parr, 

 1931). C. arctifrons occurs mainly at depths 

 of 46-366 m (25-200 fm) (Goode and Bean, 

 1895; Gutherz, 1967) and infrequently in 

 waters as shallow as 22 m (12 fm) (Bigelow 

 and Schroeder. 1953). Little additional infor- 

 mation is available on the life history of either 

 species. 



MATERIALS AND METHODS 



Specimens 



Several thousand larvae of each species, 

 fixed and stored in 3-5% Formalin.'^ were exam- 

 ined. Juveniles and adults had been fixed in 

 10% Formalin and transferred to 40% isopropyl 

 alcohol for storage. 



Larvae used in this study came mainly from 

 VIMS collections made with the RV Pathfinder 

 during three series of Atlantic plankton cruises: 

 monthly from December 1959 through De- 

 cember 1960 (October excluded) and from 

 March 1961 through March 1962, and season- 

 ally from July 1962 to April 1963 (winter ex- 

 cluded). The pattern of stations at which col- 



•^ Reference to trade names does not imply endorsement 

 by the National Marine Fisheries Service, NOAA. 



Manuscript accepted November 1972. 

 FISHERY BULLETIN: VOL. 71, NO. .1. 1973. 



735 



