Identification of menhaden eggs and larvae 

 among tiie four other clupeid genera and two 

 engrauHd genera along the North American east 

 coast was facilitated by published illustrations and 

 descriptions (Kuntz and Radcliffe 1917; Mansueti 

 and Hardy 1967; Houde and Fore 1973) and 

 reported spawning areas and times (Reintjes 1961; 

 Higham and Nicholson 1964). Menhaden larvae 

 collected north of Cape Lookout are presumed to 

 be Brevoortia tyrannus, since B. smithi occurs 

 mainly farther south and spawns inshore 

 (Reintjes 1962). The areas of larval occurrence of 

 menhaden overlap Atlantic herring, Clupea 

 harengus harengus, in the north, and round her- 

 ring, Etrumeus teres; Spanish sardine, Sardinella 

 anchovia; and Atlantic thread herring, 

 Opisthonema oglinum, in the south. 



Clupeoid larvae less than 8 mm are difficult to 

 distinguish because the median fins and other 

 characters are not formed. However, pigmenta- 

 tion, body shape, and gut length are helpful in 

 small larvae. Among clupeoid larvae the stage of 

 development at a particular size and area of cap- 

 ture are helpful. For each comparable stage of 

 larval development, menhaden are larger than 

 anchovies, Spanish sardine, and Atlantic thread 

 herring, and smaller than Atlantic herring. Only 

 round herring show the same development with 

 size as menhaden but are easily distinguished by 

 the relative length of the snout at all sizes. 



Menhaden were counted and total length 

 measurements of larvae less than 12 mm long were 

 made to the nearest 0.1 mm with an ocular 

 micrometer in a dissecting microscope; those 

 longer than 12 mm were measured with dividers 

 and a steel rule or dial calipers to the nearest 0.5 

 mm. Samples containing more than 50 fish were 

 usually randomly subsampled before measuring. 

 To get a subsample of 25-50 larvae, the sample was 

 floated in formaldehyde solution in a 150-mm petri 

 dish scribed into quarters with two diameters; a 

 random half or quarter of the dish was chosen for 

 measuring. The process was repeated with the 

 chosen fraction with samples of more than 200 

 specimens. When larvae showed slight damage, 

 such as broken caudal rays, measurements were 

 adjusted to approximate total length. Larvae 

 identifiable, but too mutilated to be measured, 

 were counted. For geographic distribution 

 analysis, numbers of larvae at each station were 

 adjusted to a standard tow as in Smith (1973) and 

 Fahay (1974). 



FISHERY BULLETIN: VOL. 73, NO. 2 



RESULTS 



Geographic Distribution of Larvae 



Menhaden larvae are more widely distributed 

 than any other clupeoid in the northwest Atlantic. 

 Larvae have been reported from Maine to Mexico 

 in oceanic, estuarine, and fresh waters. South of 

 Cape Hatteras Atlantic menhaden spawn in the 

 cooler months (October to June), while along the 

 Middle Atlantic states they spawn during the 

 warmer months (June to November). Seasonal oc- 

 currences of larvae followed the annual north- 

 south migration of adults. Small larvae were first 

 collected in June near Delaware Bay. By October 

 larvae were present from southern New England 

 to Chesapeake Bay. In late fall they were found 

 from New York to Cape Lookout. During the 

 winter and spring larger larvae were present from 

 Chesapeake Bay to Cape Lookout. 



Small menhaden larvae were collected 

 throughout the year except in late spring, in- 

 dicating nearly continual spawning (Figure 2). 

 Menhaden hatch at about 3 mm (Mansueti and 

 Hardy 1967), but we caught few less than 

 5 mm. This was probably due in part to our 

 inability to identify with certainty small larvae 

 and in part to their fragile, slender form which 

 caused them to be extruded from our nets. The 

 largest larvae we collected were 30 mm, about the 

 size at which they enter estuaries and transform 

 into juveniles (Lewis et al. 1972). 



It is not reasonable to attempt to determine a 

 growth rate for menhaden larvae from our data. 

 Small menhaden less than 8 mm were collected 

 from June through February. Thus, spawning took 

 place in our sampling area for 6 mo of the year. 

 This protracted spawning season and probable 

 geographic movements of larvae preclude the 

 possibility of determining growth rate from this 

 survey. 



Data associated with collections of menhaden 

 larvae are presented in the Appendix Table. Their 

 occurrences are illustrated in Figures 4-11. From 

 the irregular horizontal and vertical distributions 

 and highly nonnormal catch frequency curve 

 (Figure 3), it appears that the larvae are very 

 unevenly and probably patchily distributed. The 

 location and density of patches may be related to 

 local currents and water conditions on a smaller 

 scale than we sampled. This discussion follows the 

 sequence of spawning, i.e. starting in late spring 



320 



