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Snedecor, G. W., and W. G. Cochran. 



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 Ames, 507 p. 



SOKAL, R. R., AND F. J. ROHLF. 



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1977. Performance of trawls used in resource assessment. 

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 sampling gear workshop. Gulf States Mar. Fish. Comm. 

 No. 12, 80 p. 



Terry J. Cody 

 Billy E. Fuls 



Texas Parks and Wildlife Department 

 Coastal Fisheries Branch 

 4200 Smith School Road 

 Austin, TX 787U 



Long Island to Chesapeake Bay, spawning occurs 

 in offshore coastal waters from October to Decem- 

 ber and from March to May. From North Carolina 

 to Florida, spawning occurs in offshore coastal 

 waters from October through March and this spawn- 

 ing population consists of fish that have migrated 

 from the north and contains all age groups (Nichol- 

 son 1978). The gulf menhaden, which is distributed 

 zonally, is restricted to the Gulf of Mexico and 

 ranges from Cape Sable, FL, to Vera Cruz, Mexico 

 (Reintjes 1969). Their maximum reported age is ap- 

 proximately 4 yr, and they may spawn for approx- 

 imately 2 yr (Lewis and Roithmayr 1981). They 

 spawn from October through March in nearshore 

 and offshore waters within the 110 m depth contour 

 (Christmas and Waller 1975). Both species use estu- 

 aries as nursery areas for more than half their first 

 year of life. 



The major objectives of this study were to examine 

 and compare early life history characteristics of 

 these two menhadens and to investigate the effects 

 of temperature on developmental processes. Char- 

 acteristics examined were egg size, size at hatching, 

 yolk utilization rates, yolk volume at first feeding, 

 size and age at first feeding, and growth. 



EARLY LIFE HISTORY OF ATLANTIC 



MENHADEN, BREVOORTIA TYRANNUS, AND 



GULF MENHADEN, B. PATRONUS 



Atlantic menhaden, Brevoortia tyrannus, and gulf 

 menhaden, B. patronus, are allopatric, morphologi- 

 cally similar clupeids with contrasting distributional 

 patterns and reproductive traits. The Atlantic men- 

 haden has a meridional distribution and encounters 

 variable environmental conditions during its life- 

 time. It occurs along the eastern coast of North 

 America from Nova Scotia to Florida, and its dis- 

 tribution is stratified by age and size, with the older 

 and larger fish ranging farther north (Nicholson 

 1978). Atlantic menhaden are a relatively long-lived 

 clupeid. Their maximum reported age is approx- 

 imately 10 yr, and they may spawn for approximate- 

 ly 7 yr (Higham and Nicholson 1964; Nicholson 

 1975). The spatial and temporal spawning habits of 

 Atlantic menhaden are more complex than those of 

 its congener. In Long Island Sound and New Eng- 

 land waters, limited spawning occurs in inshore 

 waters during the summer and early fall. From 



Methods 



Atlantic menhaden were collected with a commer- 

 cial purse seine from the Newport River, NC, dur- 

 ing the summer. Fish were held in the laboratory 

 at ambient temperatures for approximately 4 mo 

 before spawning. Gulf menhaden were collected in 

 late September by cast net near Gulf Breeze, FL, 

 and transported to the laboratory by methods devel- 

 oped by Hettler (1983). They were held in the lab- 

 oratory at ambient temperatures for about 1 mo 

 before spawning. For each spawning, about 10 men- 

 haden were induced to spawn by methods described 

 by Hettler (1981, 1983). Eggs were spawned in 

 approximately 20 °C water during the night and col- 

 lected the following morning. All experiments ex- 

 cept those dealing specifically with growth were con- 

 ducted in 10 L rearing tanks; growth experiments 

 were conducted in 60 L rearing tanks. Tanks were 

 set in a temperature controlled water bath with two 

 40-W fluorescent lamps positioned 40 cm above each 

 tank, and the tanks were illuminated for 12 h daily. 

 Temperatures were controlled to approximately 

 ±0.5°C. Salinities ranged from 28%>o to 32%o. 

 Rotifers, Brachionus plicatilis, were used as food 

 for about the first 10 d, and Artemia nauplii and 

 rotifers were used thereafter. Feeding levels were 

 not controlled, but, based on experience, we pro- 



FISHERY BULLETIN: VOL. 84, NO. 4, 1986. 



991 



