| FishBase |
Larvae Information Summary for
Brevoortia tyrannus
| 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 |
| Back to Search |