LEWIS, WILKENS, and GORDY: YOUNG ATLANTIC MENHADEN 



o 



o 

 o 



X 



o 



7.0 10 



9.0 

 B.5 

 8.0 

 7.5 

 7.0 

 6.5 

 6.0 

 6.5 

 6.0 

 4,5' 

 4.0 

 3.5 

 3.0 

 2.5 

 2.0 

 1.5 

 1.0 

 0.5 



LENGTH (MM) 



20.0 30 40.0 60.0 80. 100 .0 



10,000.0 



I I I I 



Y = -5. 2298 + 3.1452 X 

 Juveniles 



Y = -16 9638 + 6. 3083X 

 Prejuveniles 



Y=-8.1104+3.6050X 

 Larvae 



I I 



5.000.0 



260 O 



X 

 100.0 O 



. 10.0 



I no 



2.2 2,4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 

 LENGTH (LOGe MM) 



Larval menhaden were most abundant in March, 

 prejuveniles in late March and April, and juve- 

 niles by the beginning of May (Wilkens and 

 Lewis, 1971). Large catches of larval and pre- 

 juvenile menhaden within the freshwater-low 

 salinity zone (Table 2) suggest that favorable 

 conditions for growth are present. 



Condition factors {W/V, where W = weight 

 in mg, L = length in mm, and 5 = value for the 

 slope of weight on length for each growth 

 stanza) of larvae and prejuveniles increased 

 with time as the result of growth and develop- 

 ment. The apparent lack of growth of larvae 

 and prejuveniles in the low salinity-freshwater 

 zone during April is probably due to large num- 

 bers entering this zone, putting on fast growth, 

 moving out of the zone, and being replaced by 

 new groups (Tables 2 and 3). Juveniles, which 

 have the same body form as adults and which 

 are scattered in schools throughout the estuary, 

 showed no change in condition factor with time 

 or salinity. 



Figure 2. — Regression of weight on length for larval, 

 prejuvenile, and juvenile Atlantic menhaden collected in 

 White Oak River estuary, N.C., in 1969. (We separated 

 the lengths and weights into three groups after visual 

 observation of the data and fish. Lines were then fitted 

 by least squares regression based on data in each group.) 



prejuveniles, we included specimens from 30 to 

 38 mm and 70 to 469 mg. In this stage there is a 

 rapid increase in body depth, but little increase 

 in length. Fish above 38 mm and 469 mg we 

 classed as juveniles. Huntsman' found that the 

 relation between length and weight is similar for 

 juveniles and adults. Both stages have a similar 

 body form, only their color and size being dif- 

 ferent. We did not find any adults in our estu- 

 arine study. 



Larvae enter the lower estuary and move up- 

 stream to the freshwater-low salinity zone where 

 they go through a prejuvenile stage before com- 

 pleting their transformation into juveniles. 



' Huntsman, Gene R. 1971. Growth by year class of 

 Atlantic menhaden. (Unpublished manuscript.) NMFS 

 Center for Estuarine and Menhaden Research, Beaufort, 

 NC 28516. 



LITERATURE CITED 



HUBBS, C. L., AND K. F. Lagler. 



1949. Fishes of the Great Lakes Region. Cran- 

 brook Inst. Sci., Bull. 26, 186 p. 



Lewis, R. M., W. F. Hettler, Jr., E. P. Wilkens, and 

 G. N. Johnson. 



1970. A channel net for catching larval fishes. 

 Chesapeake Sci. 11: 196-197. 



Lewis, R. M., and W. C. Mann. 



1971. Occurrence and abundance of larval Atlantic 

 menhaden, Brevoortia tyrannus, at two North 

 Carolina inlets with notes on associated species. 

 Trans. Am. Fish. Soc. 100: 296-301. 



North Carolina State Board of Health. 



1954. The White Oak River Basin. N.C. State 

 Board Health, PoUut. Surv. Rep. 2, 122 p. 



U.S. Coast and Geodetic Survey. 



1970. Tide tables. East Coast of North and South 

 America including Greenland, 1971. U.S. Coast 

 Geod. Surv., 290 p. 



Wilkens, E. P. H., and R. M. Lewis. 



1971. Abundance and distribution of young At- 

 lantic menhaden, Brevoortia tyrannus, in the 

 White Oak River estuary. North Carolina. Fish. 

 Bull., U.S. 69: 783-789. 



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