Larvae Information Summary for  Alosa aestivalis
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Main Ref: Jones, P.W., F.D. Martin and J.D. Hardy Jr. 1978
Yolk-sac larvae
  max min mod Ref.
Length at birth (mm) 5 3.1 4.3 4639
Preanal L. % TL        
Place of development planktonic
Larval area Mid-Atlantic Bight (Delaware Bay); fresh and brackish rivers
Yolk-sac spherical   pigmented Ref:  
Yolk   Oil globules more than one oil globule
Rows on tail no rows
Other melanophores on tail no other melanophores
Melanophores on head + trunk melanophores on head + trunk
Body elongate, relatively slender, head moderately deflected at hatching. 1st day: Greatest length less than 1/4 TL, markedly reduced at end of first day. Auditory vesicles poorly developed. 2nd day: Average length 5.1 mm TL; oil droplets absent from yolk mass; auditory vesicles prominent. 3rd day: Average length 5.1 mm TL; lower jaw extends beyond upper. Incipient caudal rays apparently formed at hatching. Pectorals initially absent; conspicuous and possibly rayed at one day, fin enlarged by third day. Origin of dorsal finfold relatively far back on body at hatching; dorsal finfold apparently somewhat more narrow at hatching than at one day; in recently hatched larvae ventral finfold narrow, caudal finfold small, rounded. Pigmentation: At hatching, eye completely pigmented, chromatophores scattered over ventral surface of yolk sac. Series of pigment on dorsal edge of gut from behind yolk sac to anus, occurs as elongate chromatophores to myomere 17-19 followed by irregular widely spaced pigment. Series along ventral gut from myomere 18-20 to anus. At second day, scattered chromatophores more stellate, irregular, row below pectoral fin; melanophores on upper gut enlarged, becoming stellate near vent.
Post larvae
Striking feature none
Striking shape lateral eel-like dorsal  
Striking feature none
Shape of gut tube-like
Gas bladder   early   late  
Spinal armature   early no spines late no spines
Pigmentation early
Rows on tail ventral row
Other melanophores on tail no other melanophores
Melanophores on head + trunk melanophores on trunk
Pigmentation late
Rows on tail ventral row
Other melanophores on tail no other melanophores
Melanophores on head + trunk melanophores on trunk
Urostyle region   early unpigmented late unpigmented
Peritoneum with row of melanophores
Pectorals normal melanophores at fin base
Pelvics normal (i.e. small or absent) without melanophores
4th day (after hatching): Average length 5.2 mm TL; mouth open, protuberant; auditory vesicles greatly enlarged. Yolk absorbed completely. 5th day: Average length 5.4 mm TL; mouth terminal, upper jaw extends to anterior 1/3 of eye; operculum and otoliths prominent; branchiostegals developing. 6th day: Length 6.0 mm TL; head broader than body. Ventral finfold deep at 2 mm TL; body depth increased by 14 mm TL. Pigmentation: At 5 days after hatching, elongate chromatophores at pectoral bases; melanophores along upper and lower gut in distinct rows. 6th day: Most anterior melanophores on ventral edge of body below pectoral fin typically 4, enlarged; small chromatophores above mid-lateral line. By 10.4 mm TL (and possibly smaller) double line of pigment beginning at pectoral bases, merges gradually so that lines appear to be almost straight.
Meristic characters
  max min mod Ref.
Total number of myomeres 53 47   4639
Preanal number of myomeres 45 42   4639
  L 1st feeding Ref. Months of presence of larvae
max     Jan Feb Mar Apr
min   May Jun Jul Aug
mod     Sep Oct Nov Dec
Water parameters     Metric characters
Entered by: Luna,Susan M. - 31.05.01
Modified by: Luna,Susan M. - 16.11.07
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