HETTLER: DESCRIPTION OF GULF MENHADEN 



2mm 



FIGURE 3.— Larval Brevoortia patronus: (A) 13.0 mm (28 d after hatching). (B) 16.5 mm (44 d after hatching). (C) 18.9 mm (53 d after 



hatching). 



Gulf menhaden larvae and Atlantic menhaden lar- 

 vae could not be separated morphometrically (Table 

 3, Fig. 4), but both could be separated from yellowfin 

 menhaden larvae between 10 and 20 mm (Houde and 

 Swanson 1975) by body depth, prepelvic length, and 

 head length. Snout length and eye diameter may be 

 useful to distinguish 15-25 mm specimens; snouts 

 >7% of SL and eye diameter >9% of SL probably 

 identify yellowfin menhaden. 



Myomeres 



The total number of myomeres could be counted 

 only on specimens under 17 mm in length. Although 

 the preanal myomeres could be easily counted on 

 larger specimens, the last few postanal myomeres on 

 the peduncle became indistinguishable. The number 

 of myomeres (mean = 44.6) did not change 

 significantly with length in gulf menhaden and cor- 

 responds with the number of adult vertebrae (44-46; 



mean = 44.7 not counting the hypural bones) report- 

 ed by Dahlberg (1970). Radiographs of 20 adult gulf 

 menhaden spawners used in my study showed that all 

 fish had either 45 or 46 vertebrae (counting 

 hypurals), with a mean of 45.6. During development 

 the dorsal and anal fins moved in relation to the 

 myomeres (Table 4). The anterior end of the dorsal 

 fin moved from myomere 30 forward to myomere 23, 

 numbered from head to tail. The posterior end of the 

 dorsal fin remained fixed at myomere 32. The anus 

 and the anterior end of the anal fin moved forward 

 from myomere 37 to myomere 34. The postdorsal- 

 preanal myomere count of 2 or 3 is diagnostic for 

 Brevoortia at lengths >14 mm. Atlantic menhaden 

 larvae 6-16 mm SL had a mean of 47.2 myomeres, 

 with about two more predorsal myomeres and one 

 more postanal myomere than gulf menhaden. 

 Myomere number and distribution for gulf men- 

 haden and yellowfin menhaden (Houde and Swanson 

 1975) were so similar that neither were useful for 



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