Larvae Information Summary for  Brevoortia tyrannus
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Main Ref: Fahay, M. 1983
Yolk-sac larvae
  max min mod Ref.
Length at birth (mm) 4.5 2.4    
Preanal L. % TL        
Place of development planktonic
Larval area Mid-Atlantic Bight; Delaware Bay (USA)
Yolk-sac ovoid     Ref:  
Yolk   Oil globules  
Rows on tail no rows
Other melanophores on tail no other melanophores
Melanophores on head + trunk melanophores on trunk
Eyes unpigmented at hatching. Head deflected over and attached to yolk; yolk mass large, ovoid; anus less than 1/8 TL from tip of tail; pectoral buds barely visible. At 3.3 mm TL, about 35 preanal myomeres (Ref. 40860). At 4.5 mm, head less deflected; yolk mass about 1/2 absorbed; anus about 1/5 TL from snout to tip of tail; chromatophores along dorsal surface and scattered through dorsal and ventral finfolds (Ref. 40860). Incipient rays in caudal fin. Newly hatched larvae with 10 protruding neuromasts along each side, forming primitive lateral line. Pigmentation: At hatching, eye unpigmented. Small black chromatophores along entire dorsal surface with a fine row of melanophores dorsally near base of finfold; few scattered through dorsal and ventral finfolds; fine row of melanophores ventrally on body posterior to vent. At 4.5 mm, additional pigment on ventral aspect of body posterior to yolk; chromatophores lacking in finfold.
Post larvae
Striking feature none
Striking shape lateral normal (not striking) dorsal  
Striking feature none
Shape of gut tube-like
Gas bladder   early invisible late visible
Spinal armature   early no spines late no spines
Pigmentation early
Rows on tail dorsal row
Other melanophores on tail no other melanophores
Melanophores on head + trunk no melanophores on head or trunk
Pigmentation late
Rows on tail no rows
Other melanophores on tail one dorso-ventral cluster or band
Melanophores on head + trunk no melanophores on head or trunk
Urostyle region   early pigmented late pigmented
Peritoneum with row of melanophores
Pectorals normal melanophores at fin base
Pelvics normal (i.e. small or absent) without melanophores
Body elongate, with straight gut, 70-80% TL; vent always posterior to dorsal fin; myomeres between dorsal and anal fins increase from 2 to 4; dorsal pigment present at notochord tip in small larvae; ventral pigment also present at notochord tip; high dorsal and anal fin ray counts. Pigmentation: spots along entire dorsal surface of gut and along ventral surface of posterior half of gut at 5.0 mm; dorsal spots on body disappear at about 5.7 mm. Sequence of fin formation: pectoral, dorsal, anal, caudal, pelvic (at about 8.3 mm). Enter estuaries after about 1 month as pelagic larvae at sizes of 10 mm and larger. Transformation occurs in estuaries.
Meristic characters
  max min mod Ref.
Total number of myomeres 50 45   68
Preanal number of myomeres 40 37   68
  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. - 08.08.00
Modified by: Luna,Susan M. - 13.12.01
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