STANDARD and CHITTENDEN: REPRODUCTION. MOVEMENT. AND POPULATION OF BANDED DRUM 



TABLE 7. — Pooled time-specific and cohort-specific 

 mortality estimates for Larimus fasciatus using 

 Heincke's procedure (Ricker 1975). Symbols represent: 

 ./Vo> youngest spawned group in Heincke's estimate; 

 S, annual survival rate; 1 - S, annual mortality rate; 

 and 2, instantaneous mortality rate. 



from 94.44 to 99.84** except in July 1981 when it 

 was 74.43 r r. The low estimates in June and July 

 reflect the unusual instance previously noted of 

 immigration by fish approaching age II. Pooled 

 cohort-specific estimates of 1 - S using Heincke's 

 procedure were 91.90°r for fall 1978 fish and 

 96.839? for fall 1979 fish (Table 7). 



Sex Ratio and Fecundity 



Male and female L. fasciatus appear equally 

 abundant. The observed sex ratio of 1.00 males to 

 1.02 females among 2,502 mature or maturing fish 

 examined in the period October 1979-April 1981 

 did not differ significantly from 1:1 ( \ 2 = 0.19; df = 

 1. a = 0.05). 



Mean fecundity of L. fasciatus in Gravid and 

 Ripe stages was 70,453 eggs. Observed fecundity 

 ranged from 32,333 to 143,800 eggs/female. Un- 

 transformed and log-log transformed linear re- 

 gressions of fecundity on total length and total 

 weight and related statistics are presented in 

 Table 8; the former regression is depicted in Fig- 

 ure 14. The untransformed regression is a better fit 



(100r 2 being 29.7 vs. 27.1 for length and 35.1 vs. 

 28.4 for weight), but the transformed regression 

 permits extrapolation over a broader size range. 

 Fecundity statistics were based only on Gravid 

 and Ripe fish, because residual plots for untrans- 

 formed data indicated a relationship between 

 fecundity and maturity stage (Fig. 15): maximum 

 fecundity occurred in the Gravid and Ripe stages. 



Weight, Girth, and Length Relationships 



Total weight-total length, girth-total length, 

 and standard length-total length regressions are 

 presented in Table 8 with related statistics. Total 

 length-total weight regressions for males and 

 females were not significantly different in slope 

 (F = 0.35, df = 1, 1936, a = 0.05) or in elevation 

 (F = 1.62, df - 1, 1936, a == 0.05) so one pooled 

 equation is presented for them. Total length-total 

 weight regressions for males and females pooled 

 and for immatures, males, and females pooled 

 were significantly different in slope (F = 44.87, df 

 = 1, 4808, a = 0.05), but one equation that pools 

 all sizes may be useful and is presented. Calcu- 

 lated slopes significantly exceeded (3 = 3.0 at a = 

 0.05 for both length-weight relationships (males 

 and females pooled, t = 53.06; immatures, males, 

 and females pooled, t = 60.41). 



DISCUSSION 



Spawning Periodicity 



We found that the broad April to November 

 period within which L. fasciatus spawns generally 

 agrees with many studies, including Hildebrand 

 and Cable (1934), Miller (1965), Christmas and 

 Waller (1973), and Ross (1978). However, our in- 

 terpretation is new that little or no spawning oc- 



TABLE 8. — Fecundity, total weight-total length, girth-total length, and standard length-tota 

 Larimus fasciatus with supporting statistics. All regressions were significant at « = 0.01; v is 

 regression. Measures are grams and millimeters. See Methods for symbols. 



length regressions for 

 from Ricker 's 11973) GM 



Equation 



TL 

 range 



100r 2 



Residual 

 MS 



Corrected 

 total SSx 



Corrected 

 total SSy 



GM 



FEC = -295,307 + 2.498 36 TL 

 log 10 FEC = -5.5049 - 4 7689 log 10 TL 

 FEC = -32.999 * 2.223.57 TW 

 log 10 FEC = 2.6564 - 1.3013 log, TW 



log 10 TW = -5.5981 + 3.3481 log 10 TL 



(males + females) 



log, TW = -5.4761 + 3.2883 log, TL 



(males + females f immatures) 



G = -1.21 + 0.77 TL 



TL = 2.35 + 1 29 G 



SL = -5.63 + 83 TL 



TL = 6.96 + 1.20 SL 



357 



