MORPHOLOGY AND DEVELOPMENT OF HATCHERY-CULTURED 

 AMERICAN SHAD, ALOSA SAPIDISSIMA (WILSON) 



James R. Johnson 2 and Joseph G. Loesch 3 



ABSTRACT 



Morphometries and meristics of larval Alosa sapidissima (Wilson) were examined and are described for 

 hatchery-reared samples. Alosa sapidissima morphometries and body proportion ratios change with on- 

 togeny in the larval stages. Head and snout length, eye diameter, and body depth exhibit a curvilinear 

 relationship with increasing standard length, while preanal and predorsal length show a linear relationship 

 with increasing standard length. 



Predorsal and preanal myomere counts decrease during ontogeny with corresponding anterior dorsal fin 

 migration and shortening of the gut. Other meristics indicate that median fin development is completed be- 

 tween 1 7 and 2 1 mm SL, while paired fin development is completed between 23 and 28 mm SL. A develop- 

 mental sequence of the various caudal fin components shows a distinction between preflexion, flexion, and 

 postflexion larvae. The developments of hypurals and notochord flexure are important in distinguishing lar- 

 val and early juvenile stages of development. 



Pigmentation shows a greater number and density of melanophores on cultured than field-sampled 

 specimens. Stellate melanophores are found to contract and migrate on cultured samples. A sequence of 

 pigmentation changes with ontogeny is described and compared with two sympatric species. 



The American shad, Alosa sapidissima (Wilson), is a 

 commercially and recreationally important clupeid 

 commonly found in western North Atlantic coastal 

 waters from Newfoundland, Canada, to the St. Johns 

 River, Fla. (Hildebrand 1963; Scott and Crossman 

 1973; Chittenden 1969; Leim 1924; Watson 1968). 

 Life history studies of A. sapidissima have been 

 limited primarily to the juvenile and adult stages of 

 development (Carscadden and Leggett 1975; Chit- 

 tenden 1969; Leim 1924). 



The sequence of egg development for A. sapidis- 

 sima has been adequately described by Hildebrand 

 (1963), Watson (1968), and Marcy (1976). Leim 

 (1924) described yolk-sac larvae and field-sampled 

 larvae up to 28 mm in length. Hildebrand (1963) de- 

 scribed yolk-sac larvae and briefly described the 

 larval development through the juvenile stage. 

 Mansueti and Hardy (1967), Lippson and Moran 

 (1974), and Jones et al. (1978) all summarized the 

 early development of A. sapidissima. The approach 

 previously used to describe A. sapidissima appears to 



'Contribution No. 1074, School of Marine Science, Virginia In- 

 stitute of Marine Science, College of William and Mary, Gloucester 

 Point, Va. 



department of Ichthyology, School of Marine Science, Virginia In- 

 stitute of Marine Science, College of William and Mary, Gloucester, 

 Va.; present address: Environmental Affairs Department, Rio Blan- 

 co Oil Shale Company, 2851 S. Parker Road, Suite 500, Aurora, 

 CO 80014. 



'Department of Ichthyology, School of Marine Science, Virginia In- 

 stitute of Marine Science, College of William and Mary, Gloucester 

 Point, VA 23062. 



be the static technique, which describes a few larvae 

 over selected or sampled size ranges. 



This paper describes the development of A. 

 sapidissima from yolk absorption through the 

 juvenile stage of development, using the dynamic 

 description approach of Moser and Ahlstrom( 1970). 

 Special attention is given in this work to morphology, 

 meristics, and pigmentation; early caudal osteology 

 is examined from sequential samples and a sequence 

 of ossification is also described. 



METHODS 



Eggs were cultured in a flow- through system 

 designed by Blair (1976). Apparatus used in the sys- 

 tem included three to five 10-1 culture jars. A con- 

 stant flow rate was maintained into an open trough of 

 running water. The trough contained specially 

 designed baskets fitted with saran screen for holding 

 the newly hatched A. sapidissima. Larvae were se- 

 quentially sampled daily for the first 30 d, then week- 

 ly until the end of a 100-d sampling period. Samples 

 were preserved by the method recommended by Berry 

 and Richards (1973), in 10% buffered Formalin 4 . 



Two developmental series of larvae were used. 

 Specimens in the first series were used for 

 morphometric data, pigment patterns, and larval il- 



Manuscript accepted September 1982. 

 FISHERY BULLETIN: VOL. 81, NO. 2, 1983. 



'Reference to trade names does not imply endorsement by the National Marine 

 Fisheries Service, NOAA. 



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